Resolución 2535: adopta el Código Eléctrico Nacional, versión 1993. (Sustituye el Anejo A del Reglamento 4435)

B-310-15(b)(5). Tables B-310-6 and B-310-7. (1) To obtain the ampacity of cables installed in two electrical ducts in one horizontal row with 7.5-inch (191-mm) center-to-center spacing between electrical ducts, similar to Detail 1, Figure B-310-2, multiply the ampacity shown for one duct in Tables B-310-6 and B-310-7 by 0.88. (2) To obtain the ampacity of cables installed in four electrical ducts in one horizontal row with 7.5-inch (191-mm) center-to-center spacing between electrical ducts, similar to Detail 2, Figure B-310-2, multiply the ampacity shown for three electrical ducts in Tables B-310-6 and B-310-7 by 0.94. B-310-15(b)(6). Electrical Ducts Utilized in Figure B-310-2. If spacing between electrical ducts, as shown in Figure B-310-2, is less than specified in Figure B-310-2, where electrical ducts enter equipment enclosures from underground, the ampacity of conductors contained within such electrical ducts need not be reduced. B-310-15(b)(7). Examples Showing Use of Figure B-310-1 for Electrical Duct Bank Ampacity Modifications. Figure B-310-1 is used for interpolation or extrapolation for values of Rho and load factor for cables installed in electrical ducts. The upper family of curves shows the variation in ampacity and Rho at unity load factor in terms of I₁, the ampacity for Rho = 60, and 50 percent load factor. Each curve is designated for a particular ratio I₂/I₁, where I₂ is the ampacity at Rho = 120 and 100 percent load factor. The lower family of curves shows the relationship between Rho and load factor that will give substantially the same ampacity as the indicated value of Rho at 100 percent load factor. As an example, to find the ampacity of a 500 kcmil copper cable circuit for six electrical ducts as shown in Table B-310-5: At the Rho = 60, LF = 50, I₁ = 583; for Rho = 120 and LF = 100, I₂ = 400. The ratio I₂/I₁ = 0.686. Locate Rho = 90 at bottom of chart and follow the 90 Rho line to the intersection with 100 percent load factor where the equivalent Rho = 90. Then follow the 90 Rho line to I₂/I₁ ratio of 0.686 where F = 0.74. The desired ampacity = 0.74 X 583 = 431, which agrees with the table for Rho = 90, LF = 100. To determine the ampacity for the same circuit where Rho = 80 and LF = 75, using Figure B-310-1, the equivalent Rho = 43, F = 0.855, and the desired ampacity = 0.855 X 583 = 498 amperes. Values for using Figure B-310-1 are found in the electrical duct bank ampacity tables of this appendix. Where the load factor is less than 100 percent and can be verified by measurement or calculation, the ampacity of electrical duct bank installations can be modified as shown. Different values of Rho can be accommodated in the same manner. APPENDIX B 70-857 Table B-310-1. Ampacities of Two or Three Insulated Conductors, Rated 0 through 2000 Volts, within an Overall Covering (Multiconductor Cable), in Raceway in Free Air Based on Ambient Air Temperature of 30°C (86°F) Size Temperature Rating of Conductor. See Table 310-13. Size 60°C 75°C 90°C 60°C 75°C 90°C (140°F) (167°F) (194°F) (140°F) (167°F) (194°F) TYPES TYPES TYPES TYPE TYPES TYPES AWG TW, UF RH, RHW, THHN, TW RH, RHW, THHN, AWG THHW, THW, THHW, THHW, THW, THHW, kcmil THWN, THW-2, THWN, THW-2, kcmil XHHW, THWN-2, XHHW THWN-2, ZW RHH, RHH, RWH-2, RWH-2, USE-2, USE-2, XHHW XHHW, XHHW-2, XHHW-2, ZW-2 ZW-2 COPPER ALUMINUM OR COPPER-CLAD ALUMINUM 14 16+ 18+ 21+ 14 12 20+ 24+ 27+ 16+ 18+ 21+ 12 10 27+ 33+ 36+ 21+ 25+ 28+ 10 8 36 43 48 28 33 37 8 6 48 58 65 38 45 51 6 4 66 79 89 51 61 69 4 3 76 90 102 59 70 79 3 2 88 105 119 69 83 93 2 1 102 121 137 80 95 106 1 1/0 121 145 163 94 113 127 1/0 2/0 138 166 186 108 129 146 2/0 3/0 158 189 214 124 147 167 3/0 4/0 187 223 253 147 176 197 4/0 250 205 245 276 160 192 217 250 300 234 281 317 185 221 250 300 350 255 305 345 202 242 273 350 400 274 328 371 218 261 295 400 500 315 378 427 254 303 342 500 600 343 413 468 279 335 378 600 700 376 452 514 310 371 420 700 750 387 466 529 321 384 435 750 800 397 479 543 331 397 450 800 900 415 500 570 350 421 477 900 1000 448 542 617 382 460 521 1000 Amblent For ambient temperatures other than 30°C (86°F), multiply the ampacities shown above by Ambient Temp. °C the appropriate factor shown below. Temp. °F 21-25 1.08 1.05 1.04 1.08 1.05 1.04 70-77 26-30 1.00 1.00 1.00 1.00 1.00 1.00 79-86 31-35 .91 .94 .96 .91 .94 .96 88-95 36-40 .82 .88 .91 .82 .88 .91 97-104 41-45 .71 .82 .87 .71 .82 .87 106-113 46-50 .58 .75 .82 .58 .75 .82 115-122 51-55 .41 .67 .76 .41 .67 .76 124-131 56-60 .58 .71 .58 .71 133-140 61-70 .33 .58 .33 .58 142-158 71-80 .41 .41 160-176 t Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor types marked with an obelsik (f) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum. 70-858 NATIONAL ELECTRICAL CODE Table B-310-2. Ampacities of Two or Three Single Insulated Conductors, Rated 0 through 2000 Volts, Supported on a Messenger, Based on Ambient Air Temperature of 40°C (104°F) Size Temperature Rating of Conductor. See Table 310-13. Size 75°C (167°F) 90°C (194°F) 75°C (167°F) 90°C (194°F) TYPES TYPES TYPES TYPES AWG RH, RHW, THHN, THHW, RH, RHW, THHN, THHW, AWG THHW, THW, THW-2, THWN-2, THW, THWN, RHH, XHHW, kcmil THWN, RHH, RWH-2, THHW, XHHW RHW-2, XHHW-2, kcmil XHHW, zw USE-2, XHHW, THW-2, THWN-2, XHHW-2, ZW-2 USE-2, ZW-2 COPPER ALUMINUM OR COPPER-CLAD ALUMINUM 8 57 66 44 51 8 6 76 89 59 69 6 4 101 117 78 91 4 3 118 138 92 107 3 2 135 158 106 123 2 1 158 185 123 144 1 1/0 183 214 143 167 1/0 2/0 212 247 165 193 2/0 3/0 245 287 192 224 3/0 4/0 287 335 224 262 4/0 250 320 374 251 292 250 300 359 419 282 328 300 350 397 464 312 364 350 400 430 503 339 395 400 500 496 580 392 458 500 600 553 647 440 514 600 700 610 714 488 570 700 750 638 747 512 598 750 800 660 773 532 622 800 900 704 826 572 669 900 1000 748 879 612 716 1000 Ambient For ambient temperatures other than 40°C (104°F), multiply the ampacities Ambient Temp. °C shown above by the appropriate factor shown below. Temp. °F 21-25 1.20 1.14 1.20 1.14 70-77 26-30 1.13 1.10 1.13 1.10 79-86 31-35 1.07 1.05 1.07 1.05 88-95 36-40 1.00 1.00 1.00 1.00 97-104 41-45 .93 .95 .93 .95 106-113 46-50 .85 .89 .85 .89 115-122 51-55 .76 .84 .76 .84 124-131 56-60 .65 .77 .65 .77 133-140 61-70 .38 .63 .38 .63 142-158 71-80 .45 .45 160-176 APPENDIX B 70-859 Table B-310-3. Ampacities of Multiconductor Cables with not more than Three Insulated Conductors, Rated 0 through 2000 Volts, in Free Air. Based on Ambient Air Temperature of 40°C (104°F) (For TC, MC, MI, UF, USE, and SNM cables) Size Temperature Rating of Conductor. See Table 310-13. Size 60°C 75°C 85°C 90°C 60°C 75°C 85°C 90°C AWG (140°F) (167°F) (185°F) (194°F) (140°F) (167°F) (185°F) (194°F) AWG kcmil COPPER ALUMINUM OR COPPER-CLAD ALUMINUM kcmil 18 11+ 18 16 16+ 16 14 18+ 21+ 24+ 25+ 14 12 21+ 28+ 30+ 32+ 18+ 21+ 24+ 25+ 12 10 28+ 36+ 41+ 43+ 21+ 28+ 30+ 32+ 10 8 39 50 56 59 30 39 44 46 8 6 52 68 75 79 41 53 59 61 6 4 69 89 100 104 54 70 78 81 4 3 81 104 116 121 63 81 91 95 3 2 92 118 132 138 72 92 103 108 2 1 107 138 154 161 84 108 120 126 1 1/0 124 160 178 186 97 125 139 145 1/0 2/0 143 184 206 215 111 144 160 168 2/0 3/0 165 213 238 249 129 166 185 194 3/0 4/0 190 245 274 287 149 192 214 224 4/0 250 212 274 305 320 166 214 239 250 250 300 237 306 341 357 186 240 268 280 300 350 261 337 377 394 205 265 296 309 350 400 281 363 406 425 222 287 317 334 400 500 321 416 465 487 255 330 368 385 500 600 354 459 513 538 284 368 410 429 600 700 387 502 562 589 306 405 462 473 700 750 404 523 586 615 328 424 473 495 750 800 415 539 604 633 339 439 490 513 800 900 438 570 639 670 362 469 514 548 900 1000 461 601 674 707 385 499 558 584 1000 Ambient For ambient temperatures other than 30°C (86°F), multiply the ampacities shown above by Ambient Temp. °C the appropriate factor shown below. Temp. °F 21-25 1.32 1.20 1.15 1.14 1.32 1.20 1.15 1.14 70-77 26-30 1.22 1.13 1.11 1.10 1.22 1.13 1.11 1.10 79-86 31-35 1.12 1.07 1.05 1.05 1.12 1.07 1.05 1.05 88-95 36-40 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 97-104 41-45 .87 .93 .94 .95 .87 .93 .94 .95 106-113 46-50 .71 .85 .88 .89 .71 .85 .88 .89 115-122 51-55 .50 .76 .82 .84 .50 .76 .82 .84 124-131 56-60 .65 .75 .77 .65 .75 .77 133-140 61-70 .38 .58 .63 .38 .58 .63 142-158 71-80 .33 .44 .33 .44 160-176 t Unless otherwise specifically permitted elsewhere in this Code, the overcurrent protection for conductor types marked with an obelisk (t) shall not exceed 15 amperes for No. 14, 20 amperes for No. 12, and 30 amperes for No. 10 copper; or 15 amperes for No. 12 and 25 amperes for No. 10 aluminum and copper-clad aluminum. 70-860 NATIONAL ELECTRICAL CODE Table B-310-4. Ampacities for Bare or Covered Conductors Based on 40°C (104°F) Ambient, 80°C (176°F) Total Conductor Temperature, 2 Feet (610 mm) per Second Wind Velocity Bare Copper Conductors Covered Copper Conductors AWG AWG kcmil AMPS kcmil AMPS 8 98 8 103 6 124 6 130 4 155 4 163 2 209 2 219 1/0 282 1/0 297 2/0 329 2/0 344 3/0 382 3/0 401 4/0 444 4/0 466 250 494 250 519 300 556 300 584 500 773 500 812 750 1000 750 1050 1000 1193 1000 1253 Covered AAC Bare AAC Aluminum Conductors Aluminum Conductors AWG AWG kcmil AMPS kcmil AMP 8 76 8 80 6 96 6 101 4 121 4 127 2 163 2 171 1/0 220 1/0 231 2/0 255 2/0 268 3/0 297 3/0 312 4/0 346 4/0 364 266.8 403 266.8 423 336.4 468 336.4 492 397.5 522 397.5 548 477.0 588 477.0 617 556.5 650 556.5 682 636.0 709 636.0 744 795.0 819 795.0 860 954.0 920 1033.5 968 1033.5 1017 1272 1103 1272 1201 1590 1267 1590 1381 2000 1454 2000 1527 Table B-310-5. Ampacities of Single Insulated Conductors, Rated 0 through 2000 Volts, in Nonmagnetic Underground Electrical Ducts (One Conductor per Electrical Duct) Based on Ambient Earth Temperature of 20°C (68°F), Electrical Duct Arrangement per Figure B-310-2, Conductor Temperature 75°C (167°F) Size Size 3 Electrical Ducts 6 Electrical Ducts 9 Electrical Ducts 3 Electrical Ducts 6 Electrical Ducts 9 Electrical Ducts (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) (Fig. B-310-2 Detail 4) (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) (Fig. B-310-2 Detail 4) kcmil kcmil TYPES TYPES TYPES TYPES TYPES TYPES RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE COPPER ALUMINUM OR COPPER-CLAD ALUMINUM RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 250 410 344 327 386 295 275 369 270 252 320 269 256 302 230 214 288 211 197 250 350 503 418 396 472 355 330 446 322 299 393 327 310 369 277 258 350 252 235 250 500 624 511 484 583 431 400 545 387 360 489 401 379 457 337 313 430 305 284 500 APPENDIX B 750 794 640 603 736 534 494 674 469 434 626 505 475 581 421 389 538 375 347 750 1000 936 745 700 864 617 570 776 533 493 744 593 557 687 491 453 629 432 399 1000 1250 1055 832 781 970 686 632 854 581 536 848 668 627 779 551 508 703 478 441 1250 1500 1160 907 849 1063 744 685 918 619 571 941 736 689 863 604 556 767 517 477 1500 1750 1250 970 907 1142 793 729 975 651 599 1026 796 745 937 651 598 823 550 507 1750 2000 1332 1027 959 1213 836 768 1030 683 628 1103 850 794 1005 693 636 877 581 535 2000 Ambient Ambient Temp. °C For ambient temperatures other than 20°C (68°F), multiply the ampacitles shown above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .95 .95 .95 .95 .95 .95 70-77 70-861 26-30 .90 .90 .90 .90 .90 .90 79-86 Table B-310-6. Ampacities of Three Insulated Conductors, Rated 0 through 2000 Volts, within an Overall Covering (Three-Conductor Cable) in Underground Electrical Ducts (One Cable per Electrical Duct) Based on Ambient Earth Temperature of 20°C (68°F), Electrical Duct 70-862 Arrangement per Figure B-310-2, Conductor Temperature 75°C (167°F) Size Size 1 Electrical Duct 3 Electrical Ducts 6 Electrical Ducts 1 Electrical Duct 3 Electrical Ducts 6 Electrical Ducts AWG (Fig. B-310-2 Detail 1) (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) (Fig. B-310-2 Detail 1) (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) AWG TYPES TYPES TYPES TYPES TYPES TYPES kcmil RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, kcmil THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE COPPER ALUMINUM OR COPPER-CLAD ALUMINUM RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 8 58 54 53 56 48 46 53 42 39 45 42 41 43 37 36 41 32 30 8 6 77 71 69 74 63 60 70 54 51 60 55 54 57 49 47 54 42 39 6 4 101 93 91 96 81 77 91 69 65 78 72 71 75 63 60 71 54 51 4 2 132 121 118 126 105 100 119 89 83 103 94 92 98 82 78 92 70 65 2 1 154 140 136 146 121 114 137 102 95 120 109 106 114 94 89 107 79 74 1 1/0 177 160 156 168 137 130 157 116 107 138 125 122 131 107 101 122 90 84 1/0 2/0 203 183 178 092 156 147 179 131 121 158 143 139 150 122 115 140 102 95 2/0 3/0 233 210 204 221 178 158 205 148 137 182 164 159 172 139 131 160 116 107 3/0 NATIONAL ELECTRICAL CODE 4/0 268 240 232 253 202 190 234 168 155 209 187 182 198 158 149 183 131 121 4/0 250 297 265 256 280 222 209 258 184 169 233 207 201 219 174 163 505 144 132 250 350 363 321 310 340 267 250 312 219 202 285 252 244 267 209 196 245 172 158 350 500 444 389 375 414 320 299 377 261 240 352 308 297 328 254 237 299 207 190 500 750 552 478 459 511 388 362 462 314 288 446 386 372 413 314 293 374 254 233 750 1000 628 539 518 579 435 405 522 351 321 521 447 430 480 361 336 433 291 266 1000 Ambient Ambient Temp. °C For ambient temperatures other than 20°C (68°F), multiply the ampacities shown above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .95 .95 .95 .95 .95 .95 70-77 26-30 .90 .90 .90 .90 .90 .90 79-86 Table B-310-7. Ampacities of Three Single Insulated Conductors, Rated 0 through 2000 Volts, in Underground Electrical Ducts (Three Conductors per Electrical Duct) Based on Ambient Earth Temperature of 20°C (68°F), Electrical Duct Arrangement per Figure B-310-2, Conductor Temperature 75°C (167°F) Size Size 1 Electrical Duct 3 Electrical Ducts 6 Electrical Ducts 1 Electrical Duct 3 Electrical Ducts 6 Electrical Ducts (Fig. B-310-2 Detail 1) (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) (Fig. B-310-2 Detail 1) (Fig. B-310-2 Detail 2) (Fig. B-310-2 Detail 3) AWG TYPES TYPES TYPES TYPES TYPES TYPES AWG RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, RHW, THHW, THW, THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE THWN, XHHW, USE kcmil kcmil THWN, XHHW, USE COPPER ALUMINUM OR COPPER-CLAD ALUMINUM RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO RHO 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 60 90 120 LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF LF 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 50 100 100 8 63 58 57 61 51 49 57 44 41 49 45 44 47 40 38 45 34 32 8 67 63 75 56 53 66 60 58 63 52 49 59 44 41 6 6 84 77 75 80 4 111 100 98 105 86 81 98 73 67 86 78 76 79 67 63 77 57 52 4 3 129 116 113 122 99 94 113 83 77 101 91 89 83 77 73 84 65 60 3 2 147 132 128 139 112 106 129 93 86 115 103 100 108 87 82 101 73 67 2 115 126 100 94 116 83 77 1 1 171 153 148 161 128 121 149 106 98 133 119 1/0 197 175 169 185 146 137 170 121 111 153 136 132 144 114 107 133 94 87 1/0 121 151 106 98 2/0 2/0 226 200 193 212 166 156 194 136 126 176 156 151 165 130 3/0 260 228 220 243 189 177 222 154 142 203 178 172 189 147 138 173 121 111 3/0 APPENDIX B 126 4/0 4/0 301 263 253 280 215 201 255 175 161 235 205 198 219 168 157 199 137 334 290 279 310 236 220 281 192 176 261 227 218 242 185 172 220 150 137 250 250 300 373 321 308 344 260 242 310 210 192 293 252 242 272 204 190 245 165 151 300 377 283 264 340 228 209 321 276 265 296 222 207 266 179 164 350 350 409 351 337 400 442 376 361 394 302 280 368 243 223 349 297 284 321 238 220 288 191 174 400 500 503 427 409 460 341 316 412 273 249 397 338 323 364 270 250 326 216 197 500 600 552 468 447 511 371 343 457 296 270 446 373 356 408 296 274 365 236 215 600 700 602 509 486 553 402 371 492 319 291 488 408 389 443 321 297 394 255 232 700 750 632 529 505 574 417 385 509 330 301 508 425 405 461 334 309 409 265 241 750 800 654 544 520 597 428 395 527 338 308 530 439 418 481 344 318 427 273 247 800 900 692 575 549 628 450 415 554 355 323 563 466 444 510 365 337 450 288 261 900 475 304 276 1000 1000 730 605 576 659 472 435 581 372 338 597 494 471 538 385 355 Ambient Ambient Temp. °C For ambient temperatures other than 20°C (68°F), multiply the ampacities shown above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 61-68 70-863 21-25 .95 .95 .95 .95 .95 .95 70-77 26-30 .90 .90 .90 .90 .90 .90 79-86 70-864 NATIONAL ELECTRICAL CODE Table B-310-8. Ampacities of Two or Three Insulated Conductors, Rated 0 through 2000 Volts, Cabled within an Overall (Two-or-Three Conductor) Covering, Directly Buried in Earth Based on Ambient Earth Temperature of 20°C (68°F), Arrangement per Figure B-310-2, 100 Percent Load Factor, Thermal Resistance (RHO) of 90 Size Size 1 Cable 2 Cables 1 Cable 2 Cables (Fig. B-310-2 (Fig. B-310-2 (Fig. B-310-2 (Fig. B-310-2 Detail 5) Detail 6) Detail 5) Detail 6) 60°C 75°C 60°C 75°C 60°C 75°C 60°C 75°C (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) TYPES TYPES TYPES TYPES RHW, RHW, RHW, RHW, THHW, THHW, THHW, THHW, THW, THW, THW, THW, AWG UF THWN, UF THWN, UF THWN, UF THWN, AWG XHHW, XHHW, XHHW, XHHW, kcmll USE USE USE USE kcmil ALUMINUM OR COPPER-CLAD COPPER ALUMINUM 8 64 75 60 70 51 59 47 55 8 6 85 100 81 95 68 75 60 70 6 4 107 125 100 117 83 97 78 91 4 2 137 161 128 150 107 126 110 117 2 1 155 182 145 170 121 142 113 132 1 1/0 177 208 165 193 138 162 129 151 1/0 2/0 201 236 188 220 157 184 146 171 2/0 3/0 229 269 213 250 179 210 166 195 3/0 4/0 259 304 241 282 203 238 188 220 4/0 250 333 308 261 241 250 350 401 370 315 290 350 500 481 442 381 350 500 750 585 535 473 433 750 1000 657 600 545 497 1000 Ambient For ambient temperatures other than 20°C (68°F), multiply the ampacities shown above by Ambient Temp. °C the appropriate factor shown below. Temp. °F 6-10 1.12 1.09 1.12 1.09 1.12 1.09 1.12 1.09 43-50 11-15 1.06 1.04 1.06 1.04 1.06 1.04 1.06 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .94 .95 .94 .95 .94 .95 .94 .95 70-77 26-30 .87 .90 .87 .90 .87 .90 .87 .90 79-86 For ampacities of UF cable in underground electrical ducts, multiply the ampacities shown in the table by 0.74. APPENDIX B 70-865 Table B-310-9. Ampacities of Three Triplexed Single Insulated Conductors, Rated 0 through 2000 Volts, Directly Buried in Earth Based on Ambient Earth Temperature of 20°C (68°F), Arrangement per Figure B-310-2, 100 Percent Load Factor, Thermal Resistance (RHO) of 90 Size Size See See See See Fig. B-310-2 Fig. B-310-2 Fig. B-310-2 Fig. B-310-2 Detail 7 Detail 8 Detail 7 Detail 8 60°C 75°C 60°C 75°C 60°C 75°C 60°C 75°C (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) AWG TYPES TYPES TYPES TYPES AWG kcmil UF USE UF USE UF USE UF USE kcmil ALUMINUM OR COPPER-CLAD COPPER ALUMINUM 8 72 84 66 77 55 65 51 60 8 6 91 107 84 99 72 84 66 77 6 4 119 139 109 128 92 108 85 100 4 2 153 179 140 164 119 139 109 128 2 1 173 203 159 186 135 158 124 145 1 1/0 197 231 181 212 154 180 141 165 1/0 2/0 223 262 205 240 175 205 159 187 2/0 3/0 254 298 232 272 199 233 181 212 3/0 4/0 289 339 263 308 226 265 206 241 4/0 250 370 336 289 263 250 350 445 403 349 316 350 500 536 483 424 382 500 750 654 587 525 471 750 1000 744 665 608 544 1000 Ambient For ambient temperatures other than 20°C (68°F), multiply the ampacities shown above by Ambient Temp. °C the appropriate factor shown below. Temp. °F 6-10 1.12 1.09 1.12 1.09 1.12 1.09 1.12 1.09 43-50 11-15 1.06 1.04 1.06 1.04 1.06 1.04 1.06 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .94 .95 .94 .95 .94 .95 .94 .95 70-77 26-30 .87 .90 .87 .90 .87 .90 .87 .90 79-86 70-866 NATIONAL ELECTRICAL CODE Table B-310-10. Ampacities of Three Single Insulated Conductors, Rated 0 through 2000 Volts, Directly Buried in Earth Based on Ambient Earth Temperature of 20°C (68°F), Arrangement per Figure B-310-2, 100 Percent Load Factor, Thermal Resistance (RHO) of 90 Size Size See See See See Fig. B-310-2 Fig. B-310-2 Fig. B-310-2 Fig. B-310-2 Detail 9 Detail 10 Detail 9 Detail 10 60°C 75°C 60°C 75°C 60°C 75°C 60°C 75°C (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) (140°F) (167°F) AWG TYPES TYPES TYPES TYPES AWG kcmil UF USE UF USE UF USE UF USE kcmil ALUMINUM OR COPPER-CLAD ALU- COPPER MINUM 8 84 98 78 92 66 77 61 72 8 6 107 126 101 118 84 98 78 92 6 4 139 163 130 152 108 127 101 118 4 2 178 209 165 194 139 163 129 151 2 1 201 236 187 219 157 184 146 171 1 1/0 230 270 212 249 179 210 165 194 1/0 2/0 261 306 241 283 204 239 188 220 2/0 3/0 297 348 274 321 232 272 213 250 3/0 4/0 336 394 309 362 262 307 241 283 4/0 250 429 394 335 308 250 350 516 474 403 370 350 500 626 572 490 448 500 750 767 700 605 552 750 1000 887 808 706 642 1000 1250 979 891 787 716 1250 1500 1063 965 862 783 1500 1750 1133 1027 930 843 1750 2000 1195 1082 990 897 2000 Ambient For ambient temperatures other than 20°C (68°F), multiply the ampacities shown above by Ambient Temp. °C the appropriate factor shown below. Temp. °F 6-10 1.12 1.09 1.12 1.09 1.12 1.09 1.12 1.09 43-50 11-15 1.06 1.04 1.06 1.04 1.06 1.04 1.06 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .94 .95 .94 .95 .94 .95 .94 .95 70-77 26-30 .87 .90 .87 .90 .87 .90 .87 .90 79-86 APPENDIX B 70-867 1.15 1.10 1.05 1.00 1,00 .95 0.95 0.95 .90 0.90 .85 0.90 0.85 .80 -F- 0.80 0.85 I .75 0.75 0.80 Ratio 12/1 .70 0.70 .65 0.75 0.65 .60 0.70 0.60 :55 0.65 0.55 .50 0.60 0.50 .45 0.55 40 0.50 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 100 95 90 85 80 75 70 Load Factor 65 60 55 50 45 40 35 30 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 RHO Figure B-310-1. Interpolation Chart for Cables in a Duct Bank I₁ = Ampacity for Rho - 60, 50 LF; I₂ = Ampacity for Rho-120, 100 LF; Desired Ampacity = F X I₁ 70-868 NATIONAL ELECTRICAL CODE a 7.51 Detail 1 A 7.5" 7.5",7.5" 7.5" 7.5",7.5" D A 11.5"x11.5" 0 Electrical duct bank 7.5" One electrical duct Detail 2 D 19"x19" 7.5 7.5' 7.5 Electrical duct bank Detail 3 Detail 4 Three electrical ducts 19"x27" 27"x27" Electrical duct bank Electrical duct bank Or Six electrical ducts Nine electrical ducts Or 0 D : 7.5' 7.5 7.5 5 0 27"x11.5" A Electrical duct bank Three electrical ducts 7.5 7.5 27"x19" Electrical duct bank Six electrical ducts 24" 24" Detail 5 Detail 6 Detail 7 Detail 8 Buried 3 Buried 3 Buried triplexed conductor Buried triplexed cables conductor cables (1 circuit) (2 circuits) cable cables 7.5' 7.5' 7.5" 7.5" 24" 7.5" 7.5' Detail 9 Detail 10 Buried single conductor Buried single conductor cables (1 circuit) cables (2 circuits) Notes for all details: 1. Minimum burial depths to top electrical ducts or Legend cables shall be in accordance with Section 300-5. Backfill Maximum depth to the top of electrical duct banks shall (earth or concrete) be 30 inches and maximum depth to the top of direct buried cables shall be 36 inches. Electrical duct 2. For two and four electrical duct installations with electrical ducts installed in a single row, see Section Cable or cables B-310-15(b)( (5). 3. For SI units: one inch = 25.4 millimeters; one foot = 305 millimeters. Figure B-310-2. Cable Installation Dimensions for Use With Tables B-5 through B-10 APPENDIX B 70-869 Figure B-310-3. Ampacities of Single Insulated Conductors Rated 0 through 5000 Volts in Underground Electrical Ducts (Three Conductors per Electrical Duct) Nine Single-Conductor Cables per Phase Based on Ambient Earth Temperature of 20°C (68°F), Conductor Temperature 75°C (167°F) Surface Design Criteria 6" N& 24" Neutral and Electrical Grounding EGC 6" Conductor (EGC) Duct = 6 inch 0 Phase Ducts = 3 to 5 inch Conductor Material = Copper 7.5 D 30" Number of Cables per Duct =3 Number of Cables per Phase = 9 7.5" 0 1. (Typical Rho Concrete = Rho Earth - 5 for all) 4 Rho PVC Duct = 650 Rho Cable Insulation = 500 Rho Cable Jacket = 650 7.5" 7.5' 27" NOTES: Neutral configuration per Section 300-5(i), Exception No. 2 for isolated phase installations in nonmagnetic ducts. Phasing is A, B, C in rows or columns. Where magnetic electrical ducts are used, conductors are installed A, B, C per electrical duct with the neutral and all equipment grounding conductors in the same electrical duct. In this case, the 6-inch trade size neutral duct is eliminated. Maximum harmonic loading on the neutral conductor cannot exceed 50 percent of the phase current for the ampacities shown in the table. Metallic shields of Type MV-75 cable shall be grounded at one point only where using A, B, C phasing in rows or columns. For SI units: one inch = 25.4 millimeters. Size Types Size RHW, THHW, THW, THWN, XHHW, USE, OR MV-75 kcmil Total Per Phase Ampere Rating kcmil RHO EARTH 60 RHO EARTH 90 RHO EARTH 120 LF 50 LF 100 LF 100 250 2340 1530 1395 250 (260A/Cable) (170A/Cable) (155A/Cable) 350 2790 1800 1665 350 (310A/Cable) (200A/Cable) (185A/Cable) 500 3375 2160 1980 500 (375A/Cable) (240A/Cable) (220A/Cable) For ambient temperatures other than 20°C (68°F), multiply the ampacities shown Ambient Ambient Temp. °C above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .95 .95 .95 .95 .95 70-77 26-30 .90 .90 .90 .90 .90 79-86 70-870 NATIONAL ELECTRICAL CODE Figure B-310-4. Ampacities of Single Insulated Conductors Rated 0 through 5000 Volts in Nonmagnetic Underground Electrical Ducts (One Conductor per Electrical Duct) Four Single-Conductor Cables per Phase Based on Ambient Earth Temperature of 20°C (68°F), Conductor Temperature 75°C (167°F) Surface 6" N & EGC 6 24" D 0 AO 0 10 0 38" BO Design Criteria 10 D 0 Neutral and Electrical Grounding Conductor Duct = 6 inch CO Phase Ducts = 3 inch (min.) Conductor Material = Copper Number of Cables per Duct = 1 Number of Cables per Phase = 4 10 10 10 Rho Concrete = Rho Earth - 5 Rho PVC Duct = 650 44" Rho Cable Insulation = 500 Rho Cable Jacket = 650 NOTES: Neutral configuration per Section 300-5(i), Exception No. 2. Maximum harmonic loading on the neutral conductor cannot exceed 50 percent of the phase current for the ampacities shown in the table. Metallic shields of Type MV-75 cable shall be grounded at one point only. For SI units, one inch = 25.4 millimeters. Size Types Size RHW, THHW, THW, THWN, XHHW, USE, OR MV-75 kcmil Total Per Phase Ampere Rating kcmil RHO EARTH 60 RHO EARTH 90 RHO EARTH 120 LF 50 LF 100 LF 100 750 2520 1860 1680 750 (705A/Cable) (465A/Cable) (420A/Cable) 1000 3300 2140 1920 1000 (825A/Cable) (535A/Cable) (480A/Cable) 1250 3700 2380 2120 1250 (925A/Cable) (595A/Cable) (530A/Cable) 1500 4060 2580 2300 1500 (1015A/Cable) (645A/Cable) (575A/Cable) 1750 4360 2740 2460 1750 (1090A/Cable) (685A/Cable) (615A/Cable) Ambient For ambient temperatures other than 20°C (68°F), multiply the ampacities shown Temp. °C Ambient above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .95 .95 .95 .95 .95 70-77 26-30 .90 .90 .90 .90 .90 79-86 APPENDIX B 70-871 Figure B-310-5. Ampacities of Single Insulated Conductors Rated 0 through 5000 Volts in Nonmagnetic Underground Electrical Ducts (One Conductor per Electrical Duct) Five Single-Conductor Cables per Phase Based on Ambient Earth Temperature of 20°C (68°F), Conductor Temperature 75°C (167°F) Surface 6" N & 6" A 24" Design Criteria EGC Neutral and Electrical Grounding AO Conductor (EGC) Duct = 6 inch 10 38" Phase Ducts = 3 inch (min.) Conductor Material = Copper BO Number of Cables per Duct = 1 10 Number of Cables per Phase = 5 CO Rho Concrete = Rho Earth - 5 Rho PVC Duct = 650 Rho Cable Insulation = 500 10 10 10 10 Rho Cable Jacket = 650 54" NOTES: Neutral configuration per Section 300-5(i), Exception No. 2. Maximum harmonic loading on the neutral conductor cannot exceed 50 percent of the phase current for the ampacities shown in the table. Metallic shields of Type MV-75 cable shall be grounded at one point only. For SI units: one inch = 25.4 millimeters. Size Types Size RHW, THHW, THW, THWN, XHHW, USE, OR MV-75 kcmil Total Per Phase Ampere Rating kcmil RHO EARTH 60 RHO EARTH 90 RHO EARTH 120 LF 50 LF 100 LF 100 2000 5575 3375 3000 2000 (1115A/Cable) (675A/Cable) (600A/Cable) For ambient temperatures other than 20°C (68°F), multiply the Ambient Ambient Temp. °C ampacities shown above by the appropriate factor shown below. Temp. °F 6-10 1.09 1.09 1.09 1.09 1.09 43-50 11-15 1.04 1.04 1.04 1.04 1.04 52-59 16-20 1.00 1.00 1.00 1.00 1.00 61-68 21-25 .95 .95 .95 .95 .95 70-77 26-30 .90 .90 .90 .90 .90 79-86 70-872 NATIONAL ELECTRICAL CODE Table B-310-11. Adjustment Factors for More than Three Current-Carrying Conductors in a Raceway or Cable with Load Diversity Percent of Values in Number of Tables as Adjusted for Current-Carrying Ambient Temperature Conductors if Necessary 4 through 6 80 7 through 9 70 10 through 24* 70 25 through 42* 60 43 and above* 50 *These factors include the effects of a load diversity of 50 percent. (FPN): This table is based on the following formula: A₂ = V0.5 N X (A₁) where E A1 = Table ampacity multiplied by factor from Article 310, Notes to Ampacity Tables of 0 to 2000 Volts, Note 8(a). N = Total number of conductors used to obtain factor from Article 310, Notes to Ampacity Tables of 0 to 2000 Volts, Note 8(a). E = Desired number of energized conductors A₂ = Ampacity limit for energized conductors 70-873 Index ©1992 National Fire Protection Association, All Rights Reserved. The copyright in this index is separate and distinct from the copyright in the document that it indexes. The licensing provisions set forth for the document are not applicable to this index. This index may not be reproduced in whole or in part by any means without the express written permission of the National Fire Protection Association, Inc. AC and DC conductors in same enclo- Aerial cables, Art. 342; see also Nonmesure, 300-3(c)(1), 725-15 tallic extensions AC armored cable, see Armored cable, Identification, 200-6(a) Type AC Installation, 342-7(b), 820-53(d) Messenger supported wiring, Art. 321 AC resistance and reactance conversion, Chap. 9, Table 9 Agricultural buildings, Art. 547 Grounding, bonding, and equipotential AC systems Conductor to be grounded, 250-25 plane, 547-8 Lighting fixtures, 547-7 Grounding connections, 250-23(a) Motors, 547-6 Grounding electrode conductor, 250-94 Surface temperatures, 547-3 Grounding of, 250-5, 250-26 Switches, circuit breakers, controllers In same metallic enclosures, 215-4(b), and fuses, 547-5 300-20 Wiring methods, 547-4 Access and working space, electric Air conditioners, room, 440-G equipment; see also Working Branch-circuit requirements, 440-62 space Elevator machine room, 620-72 Definition, 440-60 Not over 600 volts, 110-16 Disconnecting means, 440-63 Over 600 volts, 110-B Grounding, 440-61 Substations, motion picture and TV Nameplate marking, 440-4 studio, 530-64 Air conditioning and refrigerating Switchboards, 384-8 equipment, Art. 440 Transformers, electric signs, 600-32(f) Branch circuit Accessible Conductors, 440-D Definition, Art. 100-A Ampacity, determination of, 440-6 Readily Combination loads for, 440-34 Amplifiers and rectifiers, 640-11(b) General, 440-31 Conduit bodies, junction, pull, and out- Multimotor equipment for, 440-35 let boxes, 370-19 Several motor-compressors for, Definition, Art. 100-A 440-33 Grounding electrode connection, Single motor-compressor for, 440-32 250-112 Equipment for, 440-22(b) Sealing fittings, 501-5(c), 502-5; see also General, 440-21 Hazardous (classified) locations Individual motor-compressor for, Splices and taps in auxiliary gutters, 440-22(a) 374-8(a) Outlets, 210-63 Splices and taps in wireways, 362-7 Ratings, 440-C Transformers and vaults, 450-13 Selection current Transformers, signs, outlet lighting, Definition, 440-4(c) (FPN) 600-32(e) Marking on nameplate, 440-4(c) Unfinished attics and roof spaces, Controllers for, 440-41 knob-and-tube wiring, 324-11(a) Marking, 440-5 AC-DC general-use snap switches Definitions, 440-2 Marking, 380-15 Disconnecting means, 440-B Motors, 430-83 Ex. 1 Cord-connected as, 440-13 Panelboards, use in, 384-16(b) Ratings and interrupting capacity, Ratings, type loads, 380-14 440-12 70-874 NATIONAL ELECTRICAL CODE Hermetic refrigerant motor-compressor, Antenna discharge units, 810-20 440-2 Nameplate requirements, 440-4 Antenna systems, radio and television, Overload protection, 440-F see Community antenna television Application and selection of, 440-52 and radio distribution systems; Branch-circuit conductors for, 440-52(b) Radio and television equipment General, 440-51 Apparatus Motor-compressors for, 440-52 Associated, 504-50(a) On general-purpose circuits, 440-54 Definition, 504-2 Rated-load current Intrinsically safe, 504-50(a) Definition, 440-4(a) (FPN) Definition, 504-2 Marking on nameplate, 440-4(a) Room air conditioners, see Air Appliances, Art. 422; see also Motors conditioners, room Battery-powered, 517-64(e) Single machine, when considered, 440-8 Branch circuits, see Branch circuits, Air plenums, see Plenums appliances Branch circuits for (utilization equip- Aircraft hangars, Art. 513 ment), 210-23 Aircraft batteries, 513-9 Branch-circuit calculations, 220-3 Aircraft electrical systems, 513-8 Control and protection, 422-D Aircraft energizers, 513-10 Cords, see Cords, flexible Definition, 513-1 Definition, Art. 100-A Equipment, 513-3, 513-5, 513-11 Grounding, 513-12 Disconnecting means, 422-D Locations, classification of, 513-2 Dwelling units, outlets, 210-52(b) Sealing, 513-7 Feeder calculations for, 220-10 Fixed Stanchions, rostrums, and docks, 513-6 Wiring, 513-3, 513-4 Definition, 550-2, 551-2 Grounding, 250-E, 550-11, 551-24 Airport runways, underground alarm, Hazardous (classified) locations, see signal, conductors, Table 710-3(b) Ex. 5 Hazardous (classified) locations Household cooking, demand loads for, Alarm systems, health care facilities, Table 220-19 517-32(c), 517-42(c) Installation, 422-C Alarms Load calculations, 220-3, 220-10, Table Burgler, see Remote-control, signaling, 220-19 and power-limited circuits Marking, 422-E Fire, 230-82 Ex. 5, 230-94 Ex. 4; see also Mobile homes, in, 550-7 (b) and (c), Fire protective signaling systems 550-9 Alternators, see Generators Motor-operated, load, 210-22 Overcurrent protection, 422-27 Aluminum conduit Single, 210-20, 422-27(e) In concrete and earth, 300-6(b); see also Portable Rigid metal conduit Definition, 550-2, 551-2 Aluminum siding, grounding of, Recreational vehicles, in, 551-42 250-44(e)(FPN) Signal transmission between, 517-82 Ambient temperature, 310-10; see also Stationary Temperatures, limitations Definition, 550-2, 551-2 Ampacities Subject to immersion, 422-24 Conductors, 310-15, Tables 310-16 thru Terminals, identification, 200-10(e) 310-19, B-310-1 thru 310-10, 310-61 Approval, approved thru 310-84, 374-6 Definition, Art. 100-A Crane and hoist conductors, Equipment and materials, 90-4, 90-6, Table 610-14(a) 110-2, 500-2, 500-3 Definition, Art. 100-A Fixture wires, Table 402-3 Arc lamps Flexible cords and cables, Table 400-5 General, 410-55 Portable Grounding, 250-95 Tables, 0-2000 volts, 310-16 thru 310-27, Motion picture studios, 530-17 App. B Stage equipment, 520-61 Anesthetics, flammable, 517-D; see also Arc welders, see Electric welders Hazardous (classified) locations Arcing parts, 240-41 Definition, 517-3 Enclosure of, 110-18, 430-14(b), 511-7(a), Anesthetizing locations, 517-D; see also 513-5(a), 514-4, 515-4, 516-7(b) 517- Health care facilities 61(b)(2) Definition, 517-3 Arc-welder motors, 630-C INDEX 70-875 Ampacities of conductors, Table 430- Auxiliary gutters, Art. 374 22(a) Ex. Ampacities, bare and insulated conduc- Nameplate marking, 630-24 tors, 374-6 Arenas, Art. 518, Art. 520 Clearance, bare live parts, 374-7 Emergency lighting system, Art. 700 Conductors, installation, 620-35 Construction, installation, 374-9 Armored cable, Type AC, Art. 333 Covers, 374-4 Accessible attics, 333-12 Extension beyond equipment, 374-2 Bends, 333-8 Number of conductors, 374-5 Boxes and fittings, 333-9 Sound recording, similar equipment, Conductor type, 333-20 640-4 Construction, 333-C Splices, taps, 374-8 Definition, 333-1 Supports, 374-3 Exposed work, 333-11 Use, 374-1 Marking, 333-22 Back fed devices, 384-16(f) Supports, 333-7 Backfill, 300-5(f), 339-3(a)(3), 710-3(b)(3) Through studs, joists, rafters, or parallel Ballasts, electric discharge lamps, 410-P to framing members, 333-10 Protection in fluorescent fixtures, Use, 333-3, 333-4 410-73(e) Armories, Art. 518 Protection in recessed HID fixtures; Emergency lighting system; Art. 700 410-73(f) Array, solar photovoltaic systems Bare conductors Definition, 690-2 Ampacities, Art. 310 Note 5 of Notes to Arresters, surge, see Lightning (surge) Ampacity Tables 0-2000 volts Contact conductors, cranes and hoists, arresters 610-C Askarels Definition, Art. 100-A Definition, Art. 100-A Service entrance, Type SE, USE, Transformers, 450-25 338-1(c) Assembly, places of, Art. 518 Sizing conduits for, Chap. 9, Note 4 to Table 1 Classifications, 518-2 Underground conduits, grounded neutral, Emergency lighting system, Art. 700 230-30 Ex., 230-41 Ex. Theaters, audience areas, Art. 520 Wiring methods, 518-4 Barriers, 384-3(a) Atmospheric groups, see Hazardous Basements (cellars) (classified) locations Armored cable, 333-11 Ex. 2 Attachment plugs (caps), see also Haz- Nonmetallic extensions, 342-4(b) ardous (classified) locations Nonmetallic sheathed cable, 336-12 Construction of, 410-56(f) Receptacles in, 210-8(a)(4), 210-52(g), 410-57 Definition, Art. 100-A Unfinished, 210-8(4) Flexible cords on, 400-7(b), 400-24 Grounding type, 410-58 Bathroom Polarized Definition, 210-8 Terminal identification, 200-10 Receptacles in, 210-8(a), 210-8(b) Attics Bathtubs, hydromassage, 680-G Armored cable, 333-12 Definition, 680-4 Knob and tube, 324-11 Batteries Nonmetallic-sheathed cable, 336-13 Aircraft, 513-9 Open wiring, 320-15 Installations, Art. 480, 551-10(d), 690-71 Sign transformers in, 600-32(g) Nominal voltage Audio equipment, underwater, 680-41(i) Definition, 480-2 Sealed Auditoriums, Art. 518, Art. 520 Definition, 480-2 Emergency lighting system, Art. 700 Storage, see Storage batteries Authority having jurisdiction, 90-4; see Battery charging equipment, 511-8 also Approval Aircraft hangars, 513-9 Automatic Bell circuits, see Remote-control, signal- Definition, Art. 100-A ing, and power-limited circuits Autotransformers Bends, 300-34, 334-11; see also wiring system involved Ballast for lighting units, 410-78 Branch circuits, 210-9 Block (city, town, or village), Motor starting, 430-82(b) 800-30(a)(FPN No. 1) 70-876 NATIONAL ELECTRICAL CODE Blocking diode, solar photovoltaic Vertical raceway runs, 300-19 systems Wall or ceiling, 370-20 Definition, 690-2 Wet locations, 370-15 Boatyards, see Marinas and boatyards Branch circuits, Art. 210, Art. 220 Bodies, conduit, see Conduit bodies Air conditioners, 440-D, 440-G Boilers Appliances, 422-B and C Electrode-type, 424-H Definition, Art. 100-A Resistance-type, 424-G Busways as branch circuits, 364-12 thru 364-14 Bonding, 250-G Calculation of loads, 220-3, Chap. 9 Part B Definition, Art. 100-A Car lighting, 620-22 Grounding-type receptacles, 250-74 Color code, 210-5 Hazardous (classified) locations, see Conductors, minimum ampacity and size, Hazardous (classified) locations 210-19 Intrinsically safe systems, 504-60 Critical Loosely jointed raceways, 250-77 Definition, 517-3 Other enclosures, 250-75 Definition, Art. 100-A Outside raceway, 250-79(f) Fixed electric space heating equipment, Over 250 volts, 250-76 424-3 Piping systems, 250-80 General, 210-A Receptacles, 250-74 General purpose Service equipment, 250-71, 250-72 Definition, Art. 100-A Swimming pools, 680-22 Health care facilities, 517-18(a) Bonding jumpers, see Jumpers, bonding Individual Definition, Art. 100-A Bored holes through studs, joists, Overcurrent protection, 210-20 300-4(a)(1), 545-4(b) Permissible loads, 210-23 Bowling alleys, Art. 518 Required, 520-53(g), 600-6(b), 605-8(b), Emergency lighting system, Art. 700 620-22, 710-72 Boxes (outlet, device, pull, and junc- Infrared lamps, 422-15 tion), Art. 370; see also Hazardous Isolated power systems, 517-160(c) (classified) locations Maximum loads, 210-22 Accessibility, 370-29 Mobile homes, 550-7 Concealed work, 370-24 Motor, on individual branch circuit, Conductors, number in box, 370-16 430-B Entering boxes, conduit bodies or fit- Multiwire, 210-4, 501-18, 502-18 tings, 370-17 Definition, Art. 100-A Construction specifications, 370-C Outside, Art. 225 Covers, 370-25, 370-28(c), 370-41 Overcurrent protection, 210-20, 240-3 Cutout, see Cabinets and cutout boxes Patient bed location, 517-19(a) Damp locations, 370-15 Permissible loads, 210-23 Depth, 370-24 Ratings, 210-B Exposed surface extensions, 370-22 Recreational vehicles, 551-42 Floor, for receptacles, 370-27(b) Requirements for, Table 210-24 Grounding, 250-E, 250-114, 300-9 Selection current, 440-4(c) Definition, 440-2 Insulating, see Boxes, nonmetallic Junction, pull, see Junction boxes Small appliance, 220-4(b) Stage or set, 530-22 Lighting outlets, 370-27(a), 410-C, 410-16 Metal Taps from, 210-19(c), 210-24, 240-3 Ex. 5, 240-4 Ex. 1 and 2 Construction, 370-40 Through fixtures, 410-11, 410-31 Grounding, 370-14 Two or more outlets on, 210-23 Installation, 370-B Voltage drop, 210-19(a) FPN Nonmetallic, 324-13, 336-17, 370-13, Voltage limitations, 210-6 370-17(c), 370-43 X-ray equipment, 517-E, 660-4, 660-6(b) Over 600 volts, 370-D Portable, in theaters, 520-62 Branch-circuit selection current Remote control, signal circuits, Definition, 440-2 725-11(b), 725-38(a)(2) Building component Repairing plaster around, 370-11 Definition, 545-3 Required location, 300-15 Round, 370-12 Building system Definition, 545-3 Secured supports, 300-11, 370-23 Snap switches over 300 volts, not Building wire, see Conductors ganged, 380-8(b) Buildings Unused openings, closed, 110-12(a), Definition, Art. 100-A 370-18 First floor of, 336-4(a) INDEX 70-877 Bulk storage plants, Art. 515 Cable suspension, 300-19 Class I locations, 515-2 Cable trays, Art. 318 Definition, 515-1 Ampacity, 318-11, 318-13 Gasoline dispensing, 515-7 Cable fill, 318-9, 318-10, 318-12 Grounding, 515-8 Cable installation, 318-8 Sealing, 515-6 Construction specifications, 318-5 Underground wiring, 515-5 Definition, 318-2 Wiring and equipment, 515-3, 515-4 Grounding, 318-7 Burglar alarm systems, see Remote- Installation, 318-6 control signaling and power-limited Separation, 318-6(f) Ex. 1 circuits Uses not permitted, 318-4 Buried grounding conductor connection, Uses permitted, 318-3 250-112 Ex. Cablebus, Art. 365 Busbars, auxiliary gutters, 374-6, 710-3(c) Conductors, 365-3 Bushings Overcurrent protection, 365-5 Fiber, see Fiber bushings Terminations, 365-8 Generators, 445-8 Definition, 365-1 Insulated, 373-6(c) Fittings, 365-7 Insulating, lampholders attached to Grounding, 365-9 flexible cord, 410-30 Marking, 365-10 Intermediate metal conduit, 345-15 Support, 365-6 Motors, 430-13 Conductor, 365-3(d) Outlet boxes, conduit bodies, and outlet Use, 365-2 fittings, 370-22 Cables Rigid metal conduit, 346-8 Rigid nonmetallic conduit, 347-12 Aerial entrance, 820-53(d) Snow-melting and deicing equipment, Armored, Type AC, see Armored cable 426-22(c) Border lights, theater, 520-44(b) Underground installations, 300-5(h) Continuity, 300-12 Use in lieu of box or terminal fitting, Definition, 800-2 300-16(b) Flat cable assemblies, Type FC, see Flat cable assemblies Busways, Art. 364 Flat conductor, Type FCC, see Flat con- Branch circuits, 364-12 ductor cable Branches from, 364-8 Dead ends closed, 364-7 Heating, see Heating cables Integrated gas spacer, Type IGS, see Definition, 364-2 Extension through walls and floors, 364-6 Integrated gas spacer cable Medium voltage, Type MV, see Medium Length, as branch circuits, 364-14 Marking, 364-15 voltage cable Over 600 volts, 364-B Metal-clad, Type MC, see Metal-clad cable Overcurrent protection, 364-9, 364-10, 364-13 Mineral-insulated metal-sheathed, Type Reduction in size, 364-11 MI, see Mineral-insulated metalsheathed cable Support, 364-5 Under 600 volts, 364-30 Nonmetallic-sheathed, Types NM and Use, 364-4 NMC, see Nonmetallic-sheathed cable Bypass isolation switch Nonmetallic extension, see Nonmetallic Definition, Art. 100-A extensions Cabinets, cutout boxes, and meter Optical fiber, see Optical fiber cables socket enclosures, Art. 373 Other types of, see names of systems Construction specifications, 373-B Point of entrance Damp or wet locations, 373-2 Definition, 800-2, 820-4 Definitions, Art. 100-A Power and control tray cable, Type TC, Deflection of conductors, 373-6 see Power and control tray cable In walls, 373-3 Power limited tray cable, type PLTC, Insulation at bushings, 373-6(c) 725-51(e) Switch enclosures, splices, taps, 373-8 Preassembled in nonmetallic conduit, see Unused openings, 373-4 Preassembled cable in nonmetallic Wire bending space, 373-6(b) conduit Wiring space, 373-9 Protection against physical damage, Cable bending, see type of cable 300-4 Cable end fittings, changing from cable Remote-control signaling and power limto knob-and-tube, 300-16(a) ited circuits, 725-51 Cable sheath Secured, 300-11, 370-7(b) and (c) Definition, 800-2 Service, see Service cable 70-878 NATIONAL ELECTRICAL CODE Service-entrance, Types SE and USE, Discontinued outlets, 358-13 see Service-entrance cable Header ducts, 358-5 Shielded nonmetallic, Type SNM, see Inserts, 358-9 Shielded nonmetallic cable Junction boxes, 358-7 Splices in boxes, 300-15 Markers, 358-8 Stage, 530-18(a) Number of conductors, 358-11 Through studs, joists, rafters, 300-4 Size of conductors, 358-10 Underground, 230-C, 300-5, 310-7, Uses not permitted, 358-4 710-3(b) Underground feeder and branch circuit Cellular metal floor raceways, Art. 356 Type UF, see Underground feeder Connection to cabinets and extension and branch circuit cable from cells, 356-11 Construction, 356-12 Calculations, Chap. 9, Part B; see also Loads Definitions, 356-1 Discontinued outlets, 356-7 Camping trailer Inserts, 356-10 Definition, 551-2 Junction boxes, 356-9 Canopies Markers, 356-8 Boxes and fittings, 370-15 Number of conductors, 356-5 Lighting fixtures Size of conductors, 356-4 Conductors, space for, 410-10 Uses not permitted, 356-2 Cover At boxes, 410-12 Chair lifts, see Elevators, dumbwaiters, Combustible finishes, covering escalators, moving walks, wheelrequired between canopy and box, chair lifts, and stairway chair lifts 410-13 Churches, Art. 518 Live parts exposed, 410-3 Cinder fill Capacitors, Art. 460; see also Hazardous Intermediate or rigid metal conduits and (classified) locations electrical metallic tubing, in or Conductors, 460-8 under, 345-3(c), 346-3, 348-1 Connections at services, 230-82 Rigid nonmetallic conduit, 347-2 Discharge of stored energy, 460-6 Draining charge, 460-6 Circuit breakers, Art. 240; see also Haz- Induction and dielectric heating, 665-24 ardous (classified) locations Over 600 volts, 460-B Accessibility and grouping, 380-8 X-ray equipment, 660-36 Circuits over 600 volts, 710-21 Definition, Art. 100-A Capacity, interrupting, see Interrupting Disconnection of grounded circuits, capacity 380-2(b), 514-5 Caps, see Attachment plugs Enclosures, 380-3 Cartridge fuses, 240-F General, 110-9, 240-A Disconnection, 240-40 Overcurrent protection, 230-208, 240-A CATV systems, see Community antenna Generators, 445-4 television and radio distribution Motors, 430-52, 430-58, 430-110 systems Transformers, 450-3 Ceiling fans, 680-6, 680-41(b) Panelboards, 384-B Support of, 370-27(c), 422-18 Rating, motor branch circuits, 430-58 Cell Rating, nonadjustable trip, 240-3 Ex. 4, 240-83(c) Cellular concrete floor raceways Definition, 358-2 Service overcurrent protection, 230-90, 230-91 Electrolytic Definition, 688-2 Services, disconnecting means, 230-70, 230-208 Sealed, storage batteries Definition, 480-2 Switches, use as, 240-83(d), 380-11, Solar 410-81(b) Definition, 690-2 Wet locations, in, 380-4 Cell line, electrolytic cells Circuit directory, panelboards, 110-22 Attachments and auxiliary equipment Circuit-interrupters, ground-fault, see Definition, 668-2 Ground-fault circuit-interrupters Definition, 668-2 Circuits Cellars, see Basements Anesthetizing locations, 517-63 Cellular concrete floor raceways, Bonding jumper Art. 358 Definition, Art. 100-A Connection to cabinets and other enclo- Branch, see Branch circuits sures, 358-6 Burglar alarm, see Remote-control sig- Definitions, 358-2 naling and power limited circuits INDEX 70-879 Central station, see Fire protective sig- Closed-loop and programmed power naling systems distribution,A 780 Communication, see Communication Cables and conductors, 780-6 circuits Control, 780-3 Electronic computer/data processing Hybrid cable, 780-6(a) equipment, 645-5 In same cabinet, panel, or box, Fire alarm, see Fire protective signaling 780-6(b) systems Noninterchangeability, 780-7 Grounding, Art. 250 Power limitation, in signaling circuits, Impedance, 110-10 780-5 Intrinsically safe, 504-30 Clothes closets Definition, 504-4 Heating, 424-38(c) Less than 50 volts, Art. 720 Light fixtures, 410-8 Class 1, 720-B Overcurrent devices, 240-24(d) Grounding, 250-5(a) Clothes dryers More than 600 volts, see Over 600 volts Calculations for, 220-18 Services, 230-H Feeder demand factors, Table 220-18 Motor, 430-B Grounding, 250-60 Motor control, 430-F Mobile homes, 550-10(e) Definition, 430-71 Clothing manufacturing plants, 500-7, Nonincendive Art. 503; see also Hazardous (clas- Definition, Art. 100-A sified) locations Number of, in enclosures, 90-7(b) CO/ALR Power-limited, see Remote control, sig- Receptacles, 410-56(b) naling and power-limited circuits Switches, 380-14(c) Protectors required, 800-12, 800-31, Collector rings, 675-11, 710-44 800-32 Definition, 675-2 Remote-control, Art. 725 Definition, Art. 100-A Collectors, cranes and hoists, 610-22 Motors, controllers, 430-F Color code Signal, see Remote-control, signaling, Branch circuits, 210-5 and power-limited circuits Conductors, 310-12 Telegraph, see Communications circuits Grounding conductor, 210-5, 250-57(b), Telephone, see Communications circuits 310-12(b), 400-23 Underground, see Communications Heating cables, 424-35 circuits Higher voltage to ground Ungrounded, 210-10, 215-7, 410-48 Feeders, 215-8 Panel boards, 384-3(e) Clamps, ground, 250-113, 250-115, Service-entrance conductors, 230-56 250-117 Combustible dusts, Art. 502; see also Class 1, 2, and 3 circuits, see Remote- Hazardous (classified) locations control, signaling, and power- Common grounding electrode, see Eleclimited circuits trode, grounding, common Class I, II, and III locations, see Hazard- Common neutral ous (classified) locations Feeders, 215-4 Clean surfaces, grounding conductor Outside wiring, 225-7(b) connections, 250-118 Communication circuits, Art. 800 Clearances, see also Enclosures; Space Access to electrical equipment, 800-5 Antennas, 810-3, 810-18, 810-54 Bonding, 800-40(d), 800-41(b) Community antenna systems, Art. 820 Cable marking, 800-50 Conductors Cable substitution, 800-53(e) Open, outside branch circuits and feed- Circuits requiring primary protectors, 800-12 ers, 225-18, 225-19 Conductors Service drop, 230-B Elevators, dumbwaiters, escalators, mov- Other circuits with, 800-52, 800-53(c) ing walks, 620-72 Outside and entering buildings, 800-E Lighting fixtures, 410-66, 410-76(b) Overhead, 800-10 Definition, 800-2 Live parts Essential electrical systems, 517-32(d), Auxiliary gutters, 374-7 Circuits over 600 volts, 110-B 517-42(d) Fire resistance, 800-49 Swimming pools, 680-8 Grounding, 800-33, 800-D Switchboards, panelboards, 384-7, 384-8, Health care facilities, 517-32(d), 517-F 384-10 Hybrid power and communications Climbing space, line conductors on cables, 800-3 poles, 225-14(d) Installation, 800-50, 800-52 70-880 NATIONAL ELECTRICAL CODE Lightning conductors, 800-13 Flexible metal conduit, Table 350-3 Listing of communication wires and Flexible metallic tubing, 349-12 cables, 800-4, 800-50, 800-51, General installations, 300-17 800-53 Intermediate metal conduit, 345-7 Marking, 800-50 Liquidtight flexible metal conduit, 351-6 Mobile homes, 800-41 Liquidtight flexible nonmetallic conduit, Protection, 800-C 351-25 Devices, 800-30 Maximum permitted, 300-17 Grounding, 800-40, 800-41 Outlet boxes, etc., 370-6 Requirements, 800-31, 800-32, 800-40, Remote control circuits, 725-17 800-41 Rigid metal conduit, 346-6 Types of cable, 800-51 Rigid nonmetallic conduit, 347-11 Underground circuits entering buildings, Signs, 600-21(d) 800-11 Sound recording equipment, 640-3, 640-4 Community antenna television and radio Surface raceways, 352-4, 352-25 distribution systems, Art. 820 Theaters, 520-5 Access to electrical equipment, 820-4 Underfloor raceways, 354-5 Cables Wireways, 362-5, 362-7 Aerial entrance, 820-53(d) X-ray equipment, 660-8 Definitions, 820-3 Conductors, see also Cords, flexible; Fix- Entering buildings, 820-11 ture wires Fire resistance of, 820-49 Aluminum, conductor material, 310-14 Listing and marking, 820-50, 820-51, Aluminum, properties of, Chap. 9, 820-53 Table 8 Outside, 820-10 Motors, 430-B Types of, 820-51 Ampacities of, 310-15, Tables 310-16 thru Underground, 820-11 310-19, B-310-1 thru B-310-10, Within buildings, 820-E 310-69 thru 310-83 Energy limitations, 820-2 Amplifier circuits, 640-5 Grounding, 820-D Application, 310-12, 310-13 Cables, 820-33, 820-D Armored cable, Type AC, see Armored Equipment, 820-41 cable Installation of cables and equipment, Bare, see Bare conductors 820-52 Boxes and fittings, junction, 370-16, Mobile homes, 820-42 370-17 Protection, 820-C, 820-40(5) Branch circuits, Art. 210 Buried, 310-7 Compressors, refrigeration, Art. 440 Busways, see Busways Computer rooms, see Electronic Cabinets and cutout boxes, 373-5 thru computer/data processing 373-7 equipment Cablebus, see Cablebus Concealed Capacitors, 460-8 Definition, Art. 100-A Cellular concrete floor raceways, see Knob-and-tube wiring, see Knob-and- Cellular concrete floor raceways tube wiring Cellular metal floor raceways, see Cellu- Concentric knockouts, see Knockouts, lar metal floor raceways Circuit bonding service equipment Communication, Art. 800 Concrete Control, 517-74 Electrodes encased in, 250-81(c) Fire protective signaling, Art. 760 Metal raceways and equipment in, 300-6 Less than 50 volts, Art. 720 Conductive surfaces, exposed Over 600 volts, Art. 710 Definition, 517-2 Signal, remote-control, power-limited, Art. 725 Conductor fill Combinations, Chap. 9, Table 1 Auxiliary gutters, 374-5, 374-8(a) Communications circuits, 800-B, 800-E Cable trays, 318-8, 318-9 Cellular concrete floor raceways, 358-11 Computations of, examples, Chap. 9, Part B Cellular metal floor raceways, 356-5 Concealed knob-and-tube, see Knob and Control circuits, 517-74(a) tube wiring Electrical metallic tubing, 348-6 Conduit or tubing, number in, 331-6, Electrical nonmetallic tubing, 331-6 345-7, 346-6, 347-11, 348-6, 349-12, Elevators, 620-32, 620-33 Table 350-3, 351-6, 351-25, Chap. 9 Entering boxes, conduit bodies, or fit- Tables 3A thru 3C, Table 5B tings, 370-7 Construction, general, Table 310-13 Fixture wire, 402-7 Cooling of electric equipment, 110-13(b) INDEX 70-881 Copper, 760-16 Fixtures, flush, recessed, 410-67 Ampacities, Tables 310-16 thru 310-19, Hazardous (classified) locations, Class B-310-1 thru B-310-10 I, 501-13 Properties, Chap. 9, Table 8 Motion picture projectors, 540-14 Copper-clad aluminum Theaters, 520-42 Definition, Art. 100-A Insulation at bushings, No. 4 and larger, Cords, flexible, see Cords, flexible 373-6(c) Corrosive conditions, 300-6, 310-9, Intrinsically safe, 504-30, 504-50 501-13 Length in boxes, 300-14 Covered Lighting fixtures, 410-E Definition, Art. 100-A Lightning rods, spacing from, 250-46, Crane and hoists, 610-B, 610-C, 610-31, 800-13, 820-10(e)(3) 610-41 Liquidtight flexible metallic conduit, see Definitions, Art. 100-A Liquidtight flexible metallic conduit Deflection of, see Deflection of conductors Liquidtight flexible nonmetallic conduit, Different systems, 300-3, 725-15, see Liquidtight flexible nonmetallic 725-38(a)(2) conduit Dimensions of, Chap. 9, Tables 5 thru 6 Metal-clad cable, see Metal-clad cable Electrical metallic tubing, see Electrical Metal enclosures, spacing from lighting metallic tubing rods, 250-46 Electrical nonmetallic tubing, see Electri- Mineral-insulated metal-sheathed cable, cal nonmetallic tubing see Mineral-insulated metal- Elevators, dumbwaiters, escalators, movsheathed cable ing walks, 620-B thru 620-D Minimum size, 310-5, 517-74(b) Enclosure, grounding, 250-1, 250-D Motion picture projectors, sizes, 540-13 Equipment grounding, see Equipment Motor circuits, 430-B grounding conductors Multioutlet assembly, see Multioutlet Feeder, Art. 215 assembly Fire protective signaling systems, 760-15, Multiple, 250-79(d), 250-95, 300-20, 760-16, 760-50, 760-52 310-4, 520-27(b), 620-12(a)(1) Ex. Fixture wires, Art. 402 Nonmetallic extensions, see Nonmetallic Gauges (AWG), general provisions, 110-6 extensions Generators, size, 445-5 Nonmetallic sheathed cable, Types NM Grounded, 250-23, 250-25 and NMC, see Nonmetallic- Alternating current systems, 250-23, sheathed cable 250-25 Number of, in, see Conductor fill Identification, 200-2, 210-5, 215-8 Organs, 650-4, 650-5 Change in size, 240-23 Outlet boxes, temperature limits, 410-11 Definition, Art. 100-A Outside wiring, Art. 225 Different systems, 200-6(d) Over 600 volts, Art. 710 Fuses in, 430-36 Overcurrent protection, 240-3, 240-4 Multiconductor cables, identification, Overhead, 800-10 310-12(a) Ex. 4 Paralleled, 250-79(d), 250-95, 300-20, Identification, 200-2, 210-5, 215-8, 310-4, 520-27(b), 620-12(a) (1) Ex. 310-12 Properties of, Chap. 9, Table 8 Overcurrent protection, 240-22 Raceways, number of conductors in, see Services Conductor fill Disconnection of, 230-75 Radio and television Overcurrent protection, 230-90(b) Antenna distribution systems, 810-3, Switches, disconnection, 380-2(b) Art. 820 Use and identification, Art. 200 Antenna systems, Art. 810 Grounding, see Grounding conductor Equipment, Art. 810 Grounding electrode, see Grounding Railway, power and light from, 110-19 electrode conductor Recreational vehicle site feeder circuit Identification, 310-12 Definition, 551-2 In free air, Tables 310-17, 310-19, Remote-control circuits, Art. 725 B-310-2 Rigid metal conduit, see Rigid metal con- Induction and dielectric heating equipduit ment, ampacity of supply, 665-41, Selection of, examples, Chap. 9, Part B 665-61 Service, 230-10; see also Service cables; Installation with other systems, 300-8 Service-entrance cable; and Insulated Service-entrance conductors Definition, Art. 100-A Definition, Art. 100-A Insulating materials, 310-12, 310-13 Service-entrance, see Service-entrance Insulation, Art. 310 conductors Fire protective signaling systems, 760- Shielded nonmetallic-sheathed cable, see 16(b) Shielded nonmetallic-sheathed cable 70-882 NATIONAL ELECTRICAL CODE Signal circuits, Art. 725, Art. 760 Rigid nonmetallic, see Rigid nonmetallic Signs and outline lighting, 600-21, 600-31 conduit Single, underground, 300-5(i) Connections Sizes, 110-6, Chap. 9, Tables 5 thru 6 Sound recording equipment, 640-3 thru Aluminum, copper conductors, 110-14 640-9 Cellular metal floor raceways to cabinets Stranded, 310-3 and extensions, 356-11 Support of, in vertical raceways, 300-19 Essential electrical systems, 517-34, Surface raceway, see Surface raceway 517-42, 517-43, 517-50 Switchboards and panelboards, 384-3(a), Feed-through, see Feed-through connec- 384-9 tions Temperature, limitations of, 310-10, Grounding conductor, 250-K 338-3(c) High-impedance grounded neutral sys- Theaters, portable stage equipment, tem, 250-22 520-68 Integrity of, 110-12(c) Underfloor raceway, see Underfloor Multiple circuit, see Multiple circuit connections raceway Underground feeder and branch-circuit Point of interconnected power production cable, see Underground feeder and sources, 705-12 branch-circuit cable Splices, 110-14(b) Ungrounded Switches, 380-2 Indentification, 210-4(d) Temperature limitations, 110-14(c) Services, 230-42(b), 230-90(a) Terminals, general provisions, 110-14(a) Welders, electric X-ray installations, 517-71 Ampacity of supply, 630-11, 630-21, Connectors 630-31 Armored cable, 333-9 Overcurrent protection, 630-12(b), Boxes, 370-7 630-22(b), 630-32(b) Cabinets and cutout boxes, 373-5(c) Wet locations, 225-4, 310-8 Cable, theater, 520-67 Wireways, see Wireways Electrical metallic tubing, 348-8, 348-14 X-ray equipment, 517-E, 660-6 thru 660-8 Intermediate metal conduit, 345-9 Conduit bodies Pressure (solderless) Definition, Art. 100-A Definition, Art. 100-A Number of conductors, 370-16(c) Rigid metal conduit, 346-9 Pull and junction box, 370-28 Rigid nonmetallic conduit, 347-6 Conduit fill, see also Conductor fill Constant-potential generators, Art. 445 Equipment grounding conductors, Chap. Overcurrent protection for, 445-4(a) 9, Note 2 of Notes to the tables Construction, closed Grounding conductor, Art. 310 Note 11 Definition, 545-3 of Notes to Ampacity Tables 0-2000 Construction sites volts Assured equipment grounding conductor Conduit nipples, Chap. 9, Note 3 of program, 305-6(b) Notes to the tables Extension cord sets, 305-6(b) Conduits Ground-fault circuit-interrupter, protec- Circuits, physical protection of remote tion for, 305-6(a) - control, 725-18 Continuity Conductors, number in, Chap. 9, Tables Electrical, metal raceways and cables, 1 thru 3C, Table 5B 250-75, 250-76 Dimensions, Chap. 9, Table 4 Service equipment, 250-71, 250-72 Electrical metallic tubing, see Electrical Grounding, metal boxes, grounding-type metallic tubing receptacles, 250-74, 250-114 Electrical nonmetallic tubing, see Electri- Mechanical, raceways and cables, 300-12 cal nonmetallic tubing Conductors, 300-13 Flexible metal, see Flexible metal Neutral of multiwire circuits, 300-13(b) conduit Intermediate metal, see Intermediate Continuous duty metal conduit Definition, Art. 100-A Liquidtight flexible metal, see Liquidtight Continuous industrial processes flexible metal conduit Coordination, electric system, 240-12 Liquidtight flexible nonmetallic, see Ground-fault protection, 230-95(a) Ex. 1 Liquidtight flexible nonmetallic Orderly shutdown, 430-44 conduit Power loss hazard, 240-3 Ex. 3 Metallic, grounding runs 25 ft., 250-33 Continuous load Number of conductors in, 402-7 Applications, 210-22(c), 220-3(a), Outside wiring, 225-10 220-10(b), 384-16(c) Rigid metal, see Rigid metal conduit Definition, Art. 100-A INDEX 70-883 Control, see also Hazardous (classified) Power-limited and signal circuits, locations remote-control, 725-16 Remote Pull at joints and terminals, 400-10 Induction and dielectric heating equip- Repair of, hard service, 400-9 ment, 665-47 Sound recording and similar equipment, Overcurrent protection, 240-3 grouping conductors, 640-7 Power-limited and signal circuits, Splices and taps, 400-9, 530-12 Art. 725 Construction sites, 305-4(g) X-ray equipment, 517-E, 660-B Types, Table 400-4 Control centers Heater, Tables 400-4, 422-8(a) Guarding live parts, 110-17 Tinsel Headroom, 110-16(f), 110-32 Minimum size, 400-12 Illumination at, 110-16(e), 110-34(d) Overcurrent protection, 400-13 Motor, 430-H Uses not permitted, 400-8 Working space, 110-16, 110-33, 110-34 Uses permitted, 400-7 Control circuit, 430-71 Correction factors, ambient temperature, Control drawing, 504-10(a) Tables 310-16 thru 310-19, B-310-1 Definition, 504-2 thru B-310-10 Control panels Corrosion protection, see Protection, Clearance around, elevators, 620-72 corrosion Working space, 110-16 Corrosive conditions Controllers, see also Hazardous (classi- Bushing, 430-13 fied) locations Conductor insulation, 310-9, 501-13 Cases, grounding, 250-43(d) General, 110-11 Definition, Art. 100-A, 430-81(a) Counter tops, outlets, 210-52 Enclosures, grounding, 250-43(d) Motor, 430-G Couplings Hazardous (classified) locations, 501-6, Electrical metallic tubing, 348-8 502-6, 503-4 Intermediate metal conduit, 345-9 Ratings, 430-83 Rigid metal conduit, 346-9 Resistors and reactors, see Resistors and Rigid nonmetallic conduit, 347-9 reactors Running threads at, 345-9(b), 346-9(b) Convenience outlets, see Receptacles Threaded and threadless, 250-72 Conversion table, AC conductor resis- Cove lighting, space for, 410-9 tances and reactances, Chap. 9, Covers Table 9 Auxiliary gutters, 374-4 Converters Boxes and fittings, 370-15 Phase, see Phase converters Cable, 650-5(d) Recreational vehicle Electrically operated pool, 680-26 Definition, 551-2 Faceplates, see Faceplates Cooking unit, counter-mounted, see also Pool Ranges and Ovens Definition, 680-4 Branch circuits, 210-19 Electrically operated, 680-26 Definition, Art. 100-A Wireways, 362-1 Cooling of equipment, 110-13(b) Cranes, Art. 610 Coordination, electrical systems, 240-12 Conductors, 610-B, 610-C Feeders, 240-100 (FPN), 517-17 Control, 610-F Copper conductors, see Conductors, cop- Electrolytic cells, 668-32 Flexible cords, 400-7 per Grounding, 250-7(a), 250-43(e), 610-G Copper-clad aluminum conductors, see Hazardous (classified) locations, 503-13 Conductors, Copper-clad aluminum Motors and controllers, disconnecting Cord sets, see Extension cord sets means, 430-112 Cords, see also Hazardous (classified) Overcurrent protection, 610-E locations Critical care areas, 517-15(2), 517-19 Flexible, Art. 400, 422-8 Definition, 517-3 Ampacities, Table 400-5 Cross sectional areas Identified conductors within, 200-6(c) Lampholders, insulating bushings, Conductors, Chap. 9, Tables 5 thru 8 410-30(a) Conduits, Chap. 9, Table 4 Motion picture projectors, 540-15 Current-carrying capacities, see Overcurrent protection, 240-4, 400-13 Ampacities 70-884 NATIONAL ELECTRICAL CODE Current-limiting devices, see also Circuit Diagnostic equipment, 517-73(a) breakers; Fuses Definition, 240-11 Diagrams Curtain machines, theaters, 520-48 Autotransformer overcurrent protection, Diagram 450-4 Cutout bases, see Fuseholders Cable installation dimensions, under- Cutout boxes, see also Cabinets, cutout ground, Fig. 310-1 boxes, and meter socket enclosures Feeders, 215-5 Definition, Art. 100-A Health care facility electrical systems, Cutouts Diagrams 517-41 and 517-25, 517-30 Motor feeder and branch circuits, Dia- Thermal, see Thermal cutouts gram 430-1 Cutting tables, motion picture, 530-D Service, Diagram 230-1 Damp or wet locations, 110-11; see also Spray application, dipping, and coating, Wet locations Figs. 516-1 thru 4 Boxes and fittings, 370-5 Swimming pools, 680-8 Cabinets and cutout boxes, 373-2 Dielectric heat generating equipment, Definition, Art. 100-A see Induction and dielectric heating Lampholders, 410-49 equipment Lighting fixtures, 410-4(a) Dielectric heating, see also Induction and Open wiring, 320-13 Overcurrent protection, enclosure, dielectric heating Definition, 665-2 240-32 Panelboards, 384-17 Different systems, conductors in same Receptacles, 410-57 enclosure, 210-5(a), 300-3(c), 318-6(e) and (f), 725-15, Dampers (flue), control 725-38(a)(2), 760-15, 760-18, Fixed stage equipment, 520-49 760-52(a), 760-52(b), 800-11(a), Ventilating openings, transformer vaults, 810-18(c), 820-52(a) 450-45(e) Dimensions Dance halls, Art. 518 Conductors, Chap. 9, Tables 5 thru 8 Data processing systems, see Electronic Conduits and tubing, Chap. 9, Table 4 computer/data processing equipment Dimmers, stage switchboard, 520-25, DC systems, grounding, 250-3, 250-22 520-53(e) Dead ends Dining areas, essential electrical sys- Busways, 364-7 tems, 517-42(e) Cablebus, 365-7 Dip tanks, Art. 516 Flat cable assemblies, 363-11 Wireways, 362-10 Direct burial Liquidtight flexible metal conduit, Dead front 351-4(a) Definition, Art. 100-A, 551-2; see also Over 600 volts, 710-3(b) individual articles Rigid nonmetallic conduit, 347-2(g), Stage switchboards, 520-21 Tables 300-5, 710-3(b) Definitions, Art. 100 Bulk storage plants, 515-5(a) Deflection of conductors Service stations, 514-8 Auxiliary gutters, 374-9(d) Underground feeder and branch-circuit Cabinets and cutout boxes, 373-6 cable, 339-3(a)(3) Underground service cable, 230-49, Deicing installations, see Fixed outdoor 310-7, Table 300-5 electric deicing and snow-melting equipment Disconnecting means Air-conditioning and refrigerating equip- Delta breakers, 384-16(e) ment, 440-B Delta-connected, 4-wire, 3-phase supply, Appliances, 422-D identifying high leg, 215-8, 230-56, Capacitors, 460-8(c) 384-3(e) Cranes, 610-D Demand factor, see also Loads Definitions, Art. 100-A, 551-2 Definition, Art. 100-A Electric space heating equipment, 424-C Electrolytic cells, 668-13 Detached buildings, oil-insulated trans- Electronic computer/data processing formers in, 450-26 Ex. 4 equipment, 645-2(1), 645-10 Detearing equipment, electrostatic, 516-4 Electroplating systems, 669-8, 669-9 Deteriorating agents, 110-11 Elevators, 620-F Fuses and thermal cutouts, 240-40 Device, see also specific type such as Identification, 110-22 Switching device Definition, Art. 100-A Induction and dielectric heating equipment, 665-43 INDEX 70-885 Interconnected electric power production Dustproof sources, 705-20, 705-21 Definition, Art. 100-A Irrigation machines, 675-8 Dusts, see Hazardous (classified) locations Mobile homes, 550-6 Motors and controllers, 430-H, 430-127 Dusttight Recreational vehicles, 551-43 Definition, Art. 100-A Separate building on same premises, Duty cycle, welding, 630-31(b)(FPN) 250-24(c) Duty, types Services, 230-F Definitions, Art. 100-A Connections, ahead of, 230-82, 700- 12(e) Dwellings, see also Appliances; Boxes; Over 600 volts, 230-205, 230-206 Branch circuits; Fixtures; Ground- Signs and outline lighting, 600-2(a) ing; and similar general categories Welders, resistance, 630-33 Branch-circuit voltages, 210-6(a) X-ray equipment, 517-72, 660-5, 660-24 Definitions, Art. 100-A Farm, services, 220-40(a), 220-41 Discontinued outlets, see Outlets, discon- Feeder load, calculations for, 220-10(a), tinued 220-30 thru 220-32, Chap. 9, Part B Dissimilar metals, see Metals, dissimilar Lighting fixtures, 410-75, 410-80(b) Doors, transformer vaults, 450-43, 450-44 Lighting loads for, Table 220-3(b) Panelboards as services, 384-3(c), Double insulated, appliances and tools, 384-16(a) 250-45(c), 422-8(d) Ex. Receptacle circuits required, 220-4(b) Double locknuts, see Locknuts, double Receptacle outlets required, 210-52, Drainage 680-6(a)(2) Equipment, 501-5(f) Protection by ground-fault circuit- Oil-insulated outdoor transformers, interrupters, 210-8(a), 680-6(a)(1) Ex. 450-27 Eccentric knockouts, see Knockouts, Raceways, see Raceways, drainage bonding service equipment Transformer vaults, 450-46 Elbows, metal, protection from corro- Dressing rooms sion, 300-6 Motion picture studios, 530-C Electric discharge lighting Theaters, 520-F Connection to fixtures, 410-14, 410-30(c) Drip loops More than 1000 volts, 410-Q Conductors entering buildings, 225-11, 1000 volts or less, 410-P 230-52 Signs and outline lighting, Art. 600 Service heads, 230-54 Wiring, equipment, 410-P, 410-Q Driveways Electric power production sources, see Clearance of conductors, 225-18 Generators; Interconnected electric Clearance of service drop, 230-24(b) power production sources; Solar Protection of service cables, 230-50(a) photovoltiac systems Drop, see Service drop; Voltage drop Electric signs, see Signs, electric Dry location, see also Damp or wet Electric space heating equipment, see locations Fixed electric space heating Definition, Art. 100-A equipment Dryers, clothes, see Clothes dryers Electric welders, see Welders, electric Dry-type transformers, 450-1 Ex.2, Electrical ducts 450-3(b), 450-21, 450-22 Definition, 310-15 Dual-voltage motor, locked-rotor rating, Electrical metallic tubing, Art. 348 430-7(b)(3) Bends, how made, 348-9 Duct heaters, installation of, 424-F Bends, number in one run, 348-10 Boxes and fittings, 348-13 Ducts Connectors and couplings, 348-8 Electrical, 310-15, B-310-15(b)(4) Construction and installation, 348-B Lighting fixtures in, 410-4(c) Marking, 348-15(d) Wiring in, 300-21, 300-22, 725-2(b), Minimum and maximum sizes, 348-5 760-2(b), 770-2(b), 800-51(a) and Number of conductors in, 348-6 (b), 820-53(a) Reaming of, 348-11 Dumbwaiters, see Elevators, dumbwait- Splices and taps, 348-14 ers, escalators, moving walks, Supports for, 348-12 wheelchair lifts, and stairway Threads on, 348-7 chair lifts Uses permitted, 348-1 Dust-ignitionproof, 502-1 Wet locations, in, 348-4 70-886 NATIONAL ELECTRICAL CODE Electrical noise Elevators, dumbwaiters, escalators, Grounding, 250-74 Ex. 4, 250-75 Ex. moving walks, wheelchair lifts, Panelboards, 384-20 and stairway chair lifts, Art. 620 Receptacles, 410-56(c) Cables, 620-E Electrical nonmetallic tubing, 300-4(b), Conductors, 620-B thru 620-D Art. 331 Disconnecting means and control, 620-F Bends, 331-9, 331-10 Essential electrical systems, 517-32(f), Boxes and fittings, 331-12 517-42(g) Construction, 331-C Grounding, 250-43 (e),620-J Definition, 331-1 Machine room, 620-H Installation, 331-B Overcurrent protection, 620-G Joints, 331-8 Overspeed equipment, 620-K Number of conductors in, 331-6 Wiring, 620-C Size, 331-5 Splices and taps, 331-13 Emergency systems, Art. 700; see also Supports, 331-11 Legally required standby systems; Trimming, 331-7 Optional standby systems Uses not permitted, 331-4 Capacity, 700-5 Uses permitted, 331-3 Circuit wiring, 700-B Circuits for lighting and power, 700-D, Electrically operated pool covers, see 700-E Covers, pool, electrically operated Connections at services, 230-82, 230-83 Electrodes, grounding Control, 700-E Aluminum, 250-83(e) Definitions, 517-3 Common, 250-54 Equipment approval, 700-3 Concrete encased, 250-81(c) Health care facilities, 517-30(c)(3), 517-31 Gas piping as, 250-83(a) Overcurrent protection, 700-F Made, 250-81, 250-83 Service disconnecting means, 230-83 Metal frame of building as, 250-81(b) Service-drop conductors, 230-2 Ex. 2 Metal water piping system, 250-81(a) Signals, 700-7 Resistance to ground of, 250-84 Signs, 700-8 Separately derived systems, 250-26(c) Sources of power, 700-C Electrolytic cells, Art. 668 Tests and maintenance, 700-4 Auxiliary nonelectric connections, 668-31 Transfer equipment, 700-6 Cell line conductors, 668-12 Unit equipment, 700-12(f) Cell line working zone, 668-10 Cranes and hoists, 668-32 Enamel, coating of DC cell line process power supply, Electrical metallic tubing, 348-1 668-11 General equipment, indoor use only, Definitions, 668-2 300-6(a) Disconnecting means, 668-13 Intermediate metal conduit, 345-3 Fixed electrical equipment, 668-30 Metal boxes, 370-20 Grounding, 668-15 Metal cabinets, 373-10(a) Portable electrical equipment, 668-20, Removing for grounding connections, 668-21, 668-30 250-75 Shunting means, 668-14 Rigid metal conduit, 346-1(a) Electronic computer/data processing Enclosed equipment, Art. 645 Definition, Art. 100-A Cables not in computer rooms, 645-6 Enclosures, see also Hazardous (classi- Circuits and interconnecting cables, fied) locations 645-5 Arcing parts, 110-18 Disconnecting means, 645-10 Bonding, 250-74, 250-75 Grounding, 645-15 Cabinets and cutout boxes, 373-7 thru Marking, 645-16 373-9, 373-11 Penetrations, 645-7 Circuits in, number of, 90-8(b) Special requirements for rooms with, Cranes, hoists, resistors, 610-2 645-2 Definition, Art. 100-A Uninterruptible power supplies (UPS), 645-11 Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and Electroplating systems, Art. 669 stairway chair lifts, 620-3, 620-H Branch-circuit conductors, 669-5 Grounding, 250-D Disconnecting means, 669-8, 669-9 High-intensity discharge lamp auxiliary Overcurrent protection, 669-9 equipment, 410-54 Warning signs, 669-7 Induction and dielectric heating, 665-20 Wiring methods, 669-6 Installations over 600 volts, 710-31 Electrostatic equipment, spraying and Intrinsically safe conductors in, detearing paint, 516-4 504-30(a)(2) INDEX 70-887 Overcurrent protection, 240-C Explosive atmospheres, gases, liquids, Panelboards, 384-18 dusts, ignitible fibers, lints and Radio equipment, 810-71(a) flyings, see Hazardous (classified) Signs, 600-8, 600-34(g) and (h) locations Subsurface, 110-12(b) Exposed, see also Enclosures Switches, 380-3 Conductive surfaces Underground, 110-12(b) Definition, 517-3 Energized parts, see also Live parts Extensions, boxes, and fittings, 370-12 Motors, motor circuits, and controllers, Live parts, 110-16 430-K Definition, Art. 100-A Energy-limited, Class 2 and Class 3 con- Wiring methods trol and signal circuits, 725-31 Definition, Art. 100-A Enforcement of code, 90-4, 510-2 Extension cord sets On construction sites, 305-6(b) Equipment, see also specific types of Approval, 90-4, 110-2 Overcurrent protection, 240-4 Cooling of, 110-13(b) Extensions Definition, Art. 100-A Auxiliary gutters, 374-2 Examination of, 90-7, 110-3 Boxes and fittings, exposed, 370-12 Grounding, 250-E Cellular concrete floor raceways, 358-6 Installation, general provisions, Art. 110 Cellular metal floor raceways, 356-11 Less than 50 volts, Art. 720 Flat cable assemblies, 363-14 More than 600 volts, 710-B Nonmetallic, see Nonmetallic extensions Mounting, see Mounting of equipment Underplaster, see Underplaster extensions Sealable, see Sealable equipment Wireways, 362-9, 362-11 Service Externally operable, see Operable, externally Definition, Art. 100-A Faceplates Equipment grounding conductors Grounding, 250-33, 250-42, 410-56(d) Connections at outlets, 250-74, 250-114 Material, 380-9, 410-56(d) Definition, Art. 100-A Minimum thicknesses for, 380-9, Installation, 210-7, 215-6, 250-50 Ex., 410-56(d) 250-92(b) Mobile homes, 550-10(d) Sizing, 250-95 Mounting surfaces, against, 380-10(b), Types recognized, 250-57, 250-91(b), 410-56(e) 250-92(b) Fans, ceiling, see Ceiling fans Equipment system Definition, 517-3 Farm buildings, feeder calculations, Escalators, see Elevators, dumbwaiters, 220-40; see also Agricultural buildings escalators, moving walks, wheel- Feeder assembly, mobile homes chair lifts, and stairway chair lifts Definitions, 550-2 Essential electrical systems, see also Feeders, Art. 215, Art. 220 Health care facilities Busways, 364-10 Definition, 517-3 Calculation of loads, 220-10(a), 220-30, Examples (computations), Chap. 9, Chap. 9 Part B Part B Definition, Art. 100-A Farm buildings, for, 220-40 Exciters Ground-fault circuit-interrupters, with, Leads in enclosure with other conduc- 215-9, 215-10, 517-14 tors, 300-3 (c) Ex. 3 Overcurrent protection for, 445-4(a) Grounding means, 215-6 Kitchen equipment, commercial, 220-20 Exhaust ducts, see Ducts Loads, see Loads, feeder Exit signs, see Signs, exit Mobile home parks, 550-5(a), 550-C Exits, emergency lighting for, 700-1(FPN Motion picture studios, 530-18(b) No. 3); see also Health care Motors, 430-B facilities Outside, Art. 225 Expansion joints, 250-77, 300-7(b), 347-9, Overcurrent protection, motor, 430-E 364-28, 374-7, 424-44(c), 424-98(c), Restaurants, 220-36 426-20(e), 426-22(d), 427-16 Taps, 240-21 Exs., 430-28 Ex. Explanatory material (FPN), 90-5 Feed-through connections of neutral Explosionproof apparatus, see also Hazconductors, 300-13(b) ardous (classified) locations Ferrous metals, protection from corro- Definition, Art. 100-A sion, 300-6 70-888 NATIONAL ELECTRICAL CODE Festoon lighting Fire pumps Conductor size, 225-6 Connection at services, 230-72(a) Ex., Definition, 225-6(b) 230-82 Ex. 5, 230-94 Ex. 4 Supports, outside circuits, 225-13 Emergency power supply, Art. 700 Festoons, portable stage equipment, Installations, 450-3(d) 520-65 Motor, overcurrent protection, 430-31 Fiber bushings, AC cable ends, 333-9 Remote-control circuits, 430-72 Service drops, 230-2 Ex. 1 Fibers, lint, flyings, ignitible, Art. 503, Service equipment overcurrent protecsee also Hazardous (classified) location, 230-90, Ex. 4 tions Fire spread along cables, low voltage Films, motion picture, see also Projecsystems, see type of system tors, motion picture involved such as Fire resistance of Storage vaults, 530-E cables Viewing, cutting, patching tables, 530-D Fire spread, prevention of through walls, Fine Print Notes (FPN), explanatory. floors, etc., 300-21, 725-2(a), material, 110-1 760-2(a), 770-2(a), 800-52(b), 820- Fire alarms, see Alarm systems; Alarms; 52(b) Fire protection signaling systems Fire-stopped partitions, 300-21, see also Circuits, see Fire protection signaling Firewalls systems Firewalls, wiring through, 300-21, Connections at services, 230-82 Ex. 5, 800-52(b), 820-52(b) 230-94 Ex. 4 Fittings, Art. 370; see also Wiring Meth- Fire detectors, line-type, 760-55 ods, types Conduit bodies, 370-16 Fire protective signaling systems, Definition, Art. 100-A Art. 760 Access to electrical equipment, 760-7 Fixed electric heating equipment for Circuits extending beyond one building, pipelines and vessels, Art. 427 760-5 Controls, 427-56 Classification, 760-3 Definitions, 427-2 Grounding, 250-43(i), 760-6 Disconnecting means, 427-55 Health care facilities, 517-F Grounding, 427-21, 427-29, 427-48, 517-13 Identification, 760-4 Location, 760-2 Impedance heating, 427-D Nonpower-limited circuits, 760-B Induction heating, 427-E Installation, 427-B Cable marking, 760-17 Conductors, 760-16 Nonheating leads, 427-18(a) Conductors of different circuits in same Overcurrent protection, 427-57 Resistance heating elements, 427-C raceway, etc., 760-15 Skin effect heating, 427-F Location of overcurrent devices, 760-13 Fixed electric space heating equipment, Art. 424 Multiconductor cable, 760-17 Number of conductors in raceway, etc. Boilers, protection of, 424-72(a) Branch circuits for, 424-3 and derating, 760-18 Overcurrent protection, 760-12 Cables, 424-E Area restrictions, 424-38 Power limitations, 760-11 Wiring method, 760-14, 760-17(d) Clearances, wiring Power-limited circuits, 760-C Ceilings, 424-36 Applications, 760-53 Other objects, openings, 424-39 Walls, 424-37 Cable markings, 760-50 Construction, 424-34 Cable substitutions, 760-54 Finish, ceilings, 424-42 Circuit markings, 760-22 Installation Conductors and cables, 760-50 Cables, 424-44 Fire resistance of cables, 760-49 Nonheating leads, 424-43 Installation, 760-50, 760-52 Marking, 424-35 Line-type fire detectors, 760-55 Splices, 424-40 Location of overcurrent devices, Tests, 424-45 760-24 Control and protection, 424-C Nonpower limited, 760-28(a) Controllers, 424-20(a) Overcurrent protection, 760-23 Disconnecting means, 424-19 thru Power limitations, 760-21 424-21 Separation of conductors, 760-52 Indicating, 424-21 Wiring methods and materials Overcurrent protection, 424-22 Load side, 760-28 Duct heaters, 424-F Supply side, 760-25 Air flow, 424-59 INDEX 70-889 Condensation, 424-62 Fixture wires, Art. 402 Disconnecting means, location, 424-65 Ampacities, 402-5 Elevated inlet temperature, 424-60 Grounded conductor, identification, Fan circuit interlock, 424-63 402-8 Identification, 424-58 Marking, 402-9 Installation, 424-61, 424-66 Minimum size, 402-6 Limit controls, 424-64 Number in conduits, 402-7, Chap. 9, Electrode-type boilers, 424-H Table 2 Installation, 424-B Overcurrent protection, 240-4, 402-12 Grounding, 424-14 Types, 402-3 Location Uses not permitted, 402-11 Exposed to physical damage, Uses permitted, 402-10 424-12(a) Fixtures, see Lighting fixtures Wet areas, 424-12(b) Spacing, combustible materials, 424-13 Flame spread, see Fire spread Special permission, 424-10 Flammable anesthetics, see Anesthetics, Supply conductors, 424-11 flammable Marking, 424-D Flammable gases and vapors, see Haz- Heating elements, 424-29 ardous (classified) locations Nameplate, 424-28 Overcurrent protection for, 424-22 Flammable liquids, see Hazardous (classi- Radiant heating panels and heating panel fied) locations sets, 424-J Flashers, time switches, etc., 380-5, Clearances, wiring 600-2(b), 600-8(b) Ceilings, 424-94 Flat cable assemblies, Type FC, Art. 363 Walls, 424-95 Branch-circuit rating, 363-16 Connection, 424-96 Conductor insulations for, 363-8 Definitions, 424-91 Dead ends, 363-11 Installation, 424-93, 424-98, 424-99 Definition, 363-1 Markings, 424-92 Extensions from, 363-14 Nonheating leads, 424-97 Fittings for, 363-13 Resistance-type boilers, 424-G Fixture hangers for, 363-12 Fixed equipment, grounding, 250-42 thru Identification, 363-19 250-44, 250-57, 250-58, 517-13 Installation, 363-5 Fixed outdoor electric deicing and Marking, 363-17 snow-melting equipment, Art. 426 Number of conductors in, 363-6 Branch circuits for, 210-23, 426-4 Protective covers for, 363-18 Connections, 426-24 Size of conductors in, 363-7 Cord- and plug-connected, 426-54 Splices, 363-9 Definitions, 426-2 Supports for, 363-15 Disconnecting means, 426-50 Taps and tap devices, 363-10 Equipment protection, 426-53 Terminal block identification, 363-20 General, 426-10 Uses not permitted, 363-4 Grounding, 426-27, 426-34, 426-44 Uses permitted, 363-3 Identification of, 426-13 Flat conductor cable, Type FCC, Art. 328 Impedance heating, 426-D Branch-circuit rating, 328-6 Induced currents, 426-33 Cable connections and ends, 328-11 Isolation transformer, 426-32 Construction, 328-C Personnel protection, 426-30 Conductor identification, 328-32 Voltage limitations, 426-31 Corrosion resistance, 328-33 Marking, 426-25 Insulation, 328-34 Nonheating leads, 426-22, 426-23, 426-25 Markings, 328-31 Overcurrent protection of, 426-52 Receptacles and housings, 328-36 Protection, corrosion, 426-26, 426-43 Transition assemblies, 328-37 Protection, thermal, 426-12 Definitions, 328-2 Resistance heating elements, 424-C Installation, 328-B Embedded, 426-20 Alterations, 328-19 Exposed, 426-21 Anchoring, 328-16 Skin effect heating, 426-E Cable connections and insulating ends, Conductor ampacity, 426-40 328-13, 328-15 Pull boxes, 426-41 Connections or other systems, 328-15 Single conductor, 426-42 Coverings, 328-10 Special permission, 426-14 Crossings, 328-17 Thermostats for, 426-51 Enclosure and shield connections, Use of, 426-11 328-13 Fixture stud, construction, 410-16(d) Receptacles, 328-14 70-890 NATIONAL ELECTRICAL CODE Shields, 328-12 Two-phase, Table 430-149 System height, 328-18 Direct current, Table 430-147 Polarization, 328-20 Systems alterations, 328-19 Furnaces, see Heating equipment, central Uses not permitted, 328-5 Furnaces, transformers, installation, Uses permitted, 328-4 450-26 Ex. 3 Fuseholders Flatirons, 422-13 Signals, 422-12 Cartridge fuses, 240-F Stands for, 422-11 Over 600 volts, 710-21(b) Temperature-limiting means, 422-12 Ex., Plug fuses, 240-E 422-13 Rating, motor controllers, 430-90 Type S, 240-53, 240-54 Flexible cords, see Cords, flexible Fuses, Art. 240; see also Hazardous Flexible metal conduit, Art. 350 (classified) locations Bends, 350-6 Cartridge, see Cartridge fuses Grounding, 350-5 Definition, over 600 volts, 100-B Minimum size, 350-3 Disconnecting means, 240-40 Number of conductors, 350-7 Enclosures, 240-C Supports, 350-4 Generators, constant-voltage, 445-4(a) Uses not permitted, 350-2 Group installation of motors, 430-53(c) Floating buildings, Art. 553 In parallel, not permitted, 240-8, 380-17 Bonding of noncurrent carrying metal Location in circuit, 240-21 parts, 553-11 Location on premises, 240-24 Definition, 553-2 Motor branch circuit protection, 430-D Feeder conductors, 553-6 Motor overload protection, 430-C Grounding, 553-C Multiple, see Multiple fuses Service conductors, 553-5 Plug, Edison-base type, 240-E Service equipment location, 553-4 Potential (voltage) transformers, 450-3(c) Services and feeders, installation, 553-7 Ratings, 240-6 Floors, receptacles, 210-52(a), Services over 600 volts, 230-208(c) 250-74 Ex. 3, 370-17(b) Type S, 240-53, 240-54 Flue damper control, see Dampers (flue), Future expansion and convenience, 90-7(a) control Garages, commercial, Art. 511 Fluorescent lighting fixtures, 410-P, Classification of locations, 511-2, 511-3 410-Q Definition, Art. 100-A Autotransformers in ballasts, 410-78 Electric vehicle charging, 511-9 Auxiliary equipment, remote from, Elevators, dumbwaiters, escalators, mov- 410-77 ing walks, in, 620-38 Ballast protection required, 410-73(e) Equipment, 511-4, 511-7, 511-8 Circuit breakers used to switch, Ground-fault circuit-interuption protection, 511-10 240-83(d) Connection of, 410-14, 410-30 Grounding fixed equipment, 250-43(f) Load calculations Outlets, 210-52(g) Sealing, 511-5 Ampere ratings, ballasts, 210-22(b) Branch circuits, 210-23 Wiring, 511-4, 511-6 Raceways, 410-31 Gas pipe Snap switches for, 380-14(a)(1), (b)(2) As grounding electrode, 250-83(a) Surface-mounted or recessed, Grounding conductor, connection, 410-8(b)(2), 410-8(d) 250-112 Thermal protection, 410-73(e) Gases, see Hazardous (classified) Fluoroscopic equipment, see X-ray locations equipment Gasoline bulk storage plants, see Bulk Footlights, theaters, 520-43 storage plants; see also Hazardous Disappearing, 520-43(c) (classified) locations Gasoline dispensing and service sta- Formal interpretations, 90-6 tions, Art. 514; see also Hazardous Forming shells, underwater pool lighting (classified) locations fixtures, 680-20(b) Circuit disconnects, 514-5 Definition, 680-4 Class I locations, 514-2 Fountains, 680-E Conductor insulations where exposed to (FPN), see Fine print notes gasoline, 310-9, 501-13 Definition, 514-1 Full-load current motors Equipment, 514-3, 514-4 Alternating current Sealing, 514-6 Single-phase, Table 430-148 Wiring, 514-3, 514-4, 514-8 Three-phase, Table 430-150 Gauges, conductors, 110-6 INDEX 70-891 General care areas, 517-15(1), 517-18 Goosenecks, service cables, 230-54 Definition, 517-3 "Greenfield", see Flexible metal conduit General provisions, installation of wiring Ground and equipment, Art. 110 Definition, Art. 100-A General requirements for wiring meth- Voltage to ods, Art. 300 Definition, Art. 100-A Boxes or fittings, where required, 300-15 Ground clamps, 250-113, 250-115, 250-117 Changing raceway, cable to open wiring, Ground ring, 250-81(d) 300-16 Conductors, 300-3 Grounded Different systems, 300-3(c) Definition, Art. 100-A Installation with other systems, 300-8 Effectively, 250-81(b)(FPN) Insulating bushings for raceways, CATV system, 820-30, 820-D 373-6(c) Communication system, 800-D Number and sizes of, in raceways, Definition, 100-A 300-17 Grounded conductor, see Conductors, Supporting, vertical raceways, 300-19 Grounded; Neutral Expansion joints, raceways, 300-7(b) Ground-fault circuit-interrupters Exhaust and ventilating ducts, wiring, Definition, Art. 100-A 300-22 Deicing and snow-melting equipment, Feed-through neutral connections, 426-31 Ex. 300-13(b) Electrically operated pool covers, Free length of wire at outlets, 300-14, 680-26(b) 550-10(h), 551-48(b) Fountains, 680-51(a) Grounding metal enclosures, 300-9 Garages, commercial, 511-10 Induced currents in metal enclosures, Permitted uses, 210-8, 215-9 300-20 Personnel, protection for, 426-30, 426-31 Mechanical and electrical continuity, Ex. conductors, raceways, cables, Pipeline heating, 427-26 Ex. 300-10, 300-12, 300-13 Receptacles, 210-7(d), 210-8 Over 600 volts, 110-B, 300-B, Art. 710 Bathrooms, in dwelling units, Protection against 210-8(a)(1) Corrosion, 300-6 Bathrooms in hotels and motels, Physical damage, 300-4 210-8(b) Raceways as a means of support, Boathouses, 210-8(a)(6) 300-11(b) Construction sites, at, 305-6 Raceways exposed to different tempera- Existing, 210-7(d) tures, 300-7 Garages, in dwelling units, 210-8(a)(2) Sealing, raceways, change in tempera- Health care facilities, 517-20(1) ture, 300-7(a) Kitchens in dwelling units, 210-8(a)(5) Securing and supporting, 300-11 Marinas and boatyards, 555-3 Spread of fire or products of combustion, Mobile homes, 550-8(b), 550-23(d) 300-21 Pools, 680-5, 680-6, 680-21, 680-31, Through studs, joists, rafters, 300-4(a) 680-62(a) Underground installations, 300-5, 300-37 Recreational vehicles, 551-41(c), 551-71 Voltage limitations, 300-2 Ground-fault protection Wiring in ducts, plenums, air-handling Emergency systems, not required, 700-26 spaces, 300-22 Equipment, 215-10, 240-13 Generators, Art. 445 Definition, of, Art. 100-A Bushings, 445-8 Health care facilities, 517-17 Conductor, ampacity of, 445-5 Personnel, 215-9 Emergency systems, 700-12(b) Service disconnecting means, 230-95 Essential electrical systems, 517-32(e), Grounding, Art. 250 517-42(f) AC systems, 250-5, 250-23, 250-25 Grounding, 250-6, 250-43 Air-conditioning units, 250-45 Guards for attendants, 445-7 Anesthetizing locations, 517-62 Health care facilities, 517-32(e), 517-35, Antenna, 810-15, 810-21, 810-58, 810-71 517-42(f) Appliances, 250-45, 422-16 Location, 445-2 Bonding, 250-G Marking, 445-3 Busways, over 600 volts, 364-22 Overcurrent protection, 445-4 Cablebus, 365-9 Portable, 250-6 Capacitors, 460-10 Protection of live parts, 445-6 CATV systems, 820-D Recreational vehicles, 551-7 Circuits, 250-A, 250-B Standby systems, Art. 701, 702 Less than 50 volts, 720-10 70-892 NATIONAL ELECTRICAL CODE Clothes dryers, 250-60 Separate buildings, 250-24 Clothes washers, 250-45 Separately derived systems, 250-5(d), Communications systems, 800-33, 800-D 250-26 Connections, location, 250-C, 250-K Services, 230-63 Construction sites, 305-5 Signs and outline lighting, 600-5 Continuity, 250-75 Sound recording equipment, 640-4(d) Control circuits, 725-20, 725-43 Spas and tubs, 680-41(f), 680-41(g) Control, radio equipment, 810-71(b) Surge arresters, 280-25 Cranes and hoists, 610-61 Swimming pools, 680-7, 680-21(d), DC systems, 250-3, 250-22 680-24, 680-25 Deicing, snow-melting systems, 426-27 Switchboard frames, 384-11 Dishwashers, 250-45(c) and (d) Switchboards, 384-12 Electrode system, 250-H Switches, 380-12 Electronic computer/data processing Systems, 250-A, 250-B equipment, 645-15 Theaters and similar locations, 520-81 Elevators, 620-J Tools, motor operated, 250-45 Enclosures, metal, wiring methods, 300-9 Transformers, 450-10 Equipment, cord- and plug-connected, X-ray equipment, 517-77, 660-D 250-45 Grounding conductors, 250-J Fire protective signaling circuits, 250- Connections, 250-K 43(i), 760-6 Definition, Art. 100-A Fixed electric space heating equipment, Earth as, 250-51, 250-91(c) 424-14 Enclosures, 250-D Fixed equipment, 250-42, 250-43, 250-57, Identification, multiconductor cable, 517-13 250-57(b) Ex. 3, 310-12(b) Ex. 2 Fixtures, lampholders, etc., 410-E Installation, 250-92 Material, 250-91 Fountains, 680-54, 680-55 Objectionable current over, 250-21 Freezers, 250-45 Sizes, 250-95 Generators, 445-1 Grounding electrode conductors Portable and vehicle mounted, 250-6 Connection to electrodes, 250-K Hazardous (classified) locations, 501-16, Definition, Art. 100-A 502-16, 503-16 Installation, 250-92 Health care facilities, 517-13, 517-19 Material, 250-91 Induction and dielectric heating equip- Sizing, 250-93, 250-94 ment, 665-B Grounding point Instrument transformers, relays, etc., 250-L Patient equipment Definition, 517-3 Intrinsically safe systems, 504-50 Reference Lightning surge arresters, 280-25 Definition, 517-3 Metal boxes, 370-40 Grounding-type attachment plugs, see Metal enclosures for conductors, 250-33 Attachment plugs, Grounding-type Metal faceplates, 410-18(a), 410-56(d) Group installation, motors, 430-53 Metal siding, 250-44 (FPN) Fire pumps, 230-72(b) Methods, 250-F Mobile homes, 550-11 Grouping, switches, circuit breakers, 380-8; see also Accessible More than 600 volts between conductors, 710-6, 710-7 Grouping of disconnects, 230-72 Motion picture studios, 530-20, 530-66 Guarded Motors and controllers, 430-L Definition, Art. 100-A Nonelectrical equipment, 250-44 Guarding, guards, see also Enclosures; Organs, 650-4 Live parts Over 600 volts, 300-36, 710-47, 710-60, Circuit breaker handles, 240-41(b) 710-74 Construction sites, 305-7 Over 1000 volts, 250-M Elevators, dumbwaiters, escalators, mov- Panelboards, 384-20, 517-19(d) ing walks, 620-71 Patient care areas, 517-19(c) Generators, 445-7 Portable equipment, 250-45 Handlamps, portable, 410-42(b) Radio and television, 810-15, 810-21, Induction and dielectric heating equipment, 665-B 810-58, 810-71 Lamps, theaters, dressing rooms, etc., Ranges and similar appliances, 250-60 520-44, 520-47, 520-65, 520-72 Receptacles, 210-7, 250-74, 250-114, Live parts 410-58, 517-13, 517-19(g) General, 110-17 Recreational vehicles, 551-54, 551-55, In theaters, 520-6 551-75, 551-77 On stage switchboards, 520-22 Refrigerators, 250-45(c) and (d) Motion picture studios, 530-15, 530-64 INDEX 70-893 Motors and motor controllers, 430-K, Receptacles and attachment plugs, 430-143 501-12 Over 600 volts, 110-34, 305-7, 710-3(b)(1) Sealing, fittings and compound, 501-5 Transformers, 450-8 Signal, alarm, remote-control, and com- X-ray installations, 517-77 munication systems, 501-14 Guest rooms, outlets, 210-63(b) Surge protection, 501-17 Switches, 501-6 Gutters, auxiliary, see Auxiliary gutters Transformers and capacitors, 501-2 Hallways, outlets, 200-52(h) Utilization equipment, 501-10 Handlamps, portable, 410-42(b) Wiring methods, 501-4 Hangars, aircraft, see Aircraft hangars Hazardous (classified) locations, Class Hazard current II, Art. 502 Definition, 517-3 Bonding, 502-16(a) Circuit breakers, 502-6 Hazardous areas, see Hazardous (classi- Control transformers and resistors, 502-7 fied) locations Cranes and hoists, 610-2 Hazardous atmospheres, Art. 500 Flexible cords, 502-12 Class I locations, 500-5 Fuses, 502-6 Class II locations, 500-6 Grounding, 502-16 Class III locations, 500-7 Lighting fixtures, 502-11 Special precautions and Groups A-G, Live parts, 502-15 500-3 Motor controllers, 502-6 Specific occupancies, 500-4, Art. 510 Motors and generators, 502-8 Hazardous (classified) locations, Receptacles and attachment plugs, Art. 500 502-13 Aircraft hangars, 513-2 Sealing, 502-5 Anesthetizing locations, 517-60, 517-61 Signal, alarm, remote-control, and com- Approval for class and properties, munication systems, meters, instru- 500-3(c) ments, and relays, 502-14 Bulk storage plants, 515-2 Surge protection, 502-17 Dusts, explosive, Art. 502 Switches, 502-6 Fibers, flyings, lint, highly combustible Transformers and capacitors, 502-2 material, Art. 503 Utilization equipment, 502-10 Garages, commercial, 511-2, 511-3 Ventilating piping, 502-9 Gases, flammable, Arts. 500, 501 Wiring methods, 502-4 Gasoline service stations, see Gasoline Hazardous (classified) locations, Class dispensing and service stations III, Art. 503 Group classifications, 500-3(a) and (b) Bonding, 503-16(a) Hoists, 503-13 Circuit breakers, 503-4 Inhalation anesthetizing locations, see Control transformers and resistors, 503-5 Anesthetizing locations Cranes and hoists, 503-13, 610-2 Liquids, flammable, Art. 500, 501 Flexible cords, 503-10 Marking, 500-3(b) Fuses, 503-4 Temperature, 500-3(e) and (f) Grounding, 503-16 Special precautions, 500-3 Lighting fixtures, 503-9 Spray application, dipping and coating Live parts, 503-15 processes, 516-2 Motor controllers, 503-4 Vapors, flammable, Art. 500, 501 Motors and generators, 503-6 Hazardous (classified) locations, Class I, Receptacles and attachment plugs, Art. 501 503-11 Bonding, 500-2, 501-16(a), 504-60 Signal, alarm, remote-control, and local Circuit breakers, 501-6 loudspeaker intercommunications, Conductor insulation, 501-13 503-12 Control transformers and resistors, 501-7 Storage battery charging equipment, Cranes and hoists, 610-2 503-14 Drainage of equipment, 501-5(f) Switches, 503-4 Flexible cords, 501-11 Transformers and capacitors, 503-2 Fuses, 501-6 Utilization equipment, 503-8 Grounding, 501-16 Ventilation piping, 503-7 Induction and dielectric heating equip- Wiring methods, 503-3 ment, 665-4 Headers Lighting fixtures, 501-9 Cellular concrete floor raceways, 358-2, Live parts, 501-15 358-5, 358-6, 358-9 Meters, instruments, and relays, 501-3 Cellular metal floor raceways, 356-1, Motor controllers, 501-6 356-2, 356-5, 356-6 Motors and generators, 501-8 Definition, 356-1, 358-2 70-894 NATIONAL ELECTRICAL CODE Health care facilities, Art. 517 Heating Communications, signaling systems, data Dielectric systems, less than 120 volts, nomi- Definition, 665-2 nal, 517-F Fixed electric space, see Fixed electric Other-than-patient care areas, 517-81 space heating equipment Patient care areas, 517-80 Induction Signal transmission between appli- Definition, 665-2 ances, 517-82 Heating appliances, Art. 422 Definitions, 517-3 Heating cables, Art. 424 Essential electrical systems, 517-C Heating elements Clinics, medical and dental offices, and Marking, 422-31 outpatient facilities, 517-50 Resistance Connections Definition, 427-2 Alternate power source, 517-34 Heating equipment Critical branch, 517-43 Definition, 665-2 Life safety branch, 517-42 Outside, 550-15(b) Critical branch, 517-33 Heating equipment, central, 422-7 Emergency system, 517-31 Heating panels and heating panel sets, Hospitals, 517-30 radiant, 424-J Life safety branch, 517-32 Heating, pipelines, and vessels Nursing homes and residential custodial Definition, 427-2 care facilities, 517-40 Heavy-duty lampholders Power sources, 517-35, 517-44 Branch circuits, 210-21(a), 210-23, Table General, 517-2 210-24 Inhalation anesthetizing locations, 517-D Unit loads, 220-3(c) Circuits, 517-63 Hermetic refrigerant motor compressors, Classification, 517-60 see also Air-conditioning and refrig- Grounding, 517-62 eration equipment Low-voltage equipment and instru- Ampacity and rating, 440-12(a) ments, 517-64 Definition, 440-2 Wiring and equipment, 517-61, Marking, 440-4 517-160(c) Rating and interrupting capacity, Isolated power systems, 517-19(f), 517-G 440-12(a) Grounded power systems in anesthetiz- High-impedance grounded neutral sysing locations, 517-160(c) tems, 250-27 Installation, 517-160(a) Hoists, Art. 610 Line isolation monitor, 517-160(b) Conductors, contact, 610-C Wiring and protection, 517-B Control, 610-F Applicability, 517-10 Electrolytic cells, 668-32 Critical care areas, 517-15(2), 517-19 Flexible cords, 400-7 Fixed electrical equipment, 517-13 Grounding, 250-7, 250-43, 610-G General care areas, 517-15(1), 517-18 Hazardous (classified) locations, 503-13 General installation/construction crite- Motors and controllers, disconnecting ria, 517-11 means, 430-112, 610-D Ground-fault protection, 517-17 Overcurrent protection, 610-E Grounding, 517-13 Wiring, 610-B Potential bonding, 517-14 Hoistways Receptacles, 517-13, 517-16 Definition, Art. 100-A Wet locations, 517-20 Wiring in, 620-37, 725-38(a)(3) Wiring methods, 517-12 Hood, metal, stage switchboard, 520-24 X-ray installations, 517-E Hoods for commercial cooking, lighting Connection to supply circuit, 517-71 in, 410-4(c) Control circuit conductors, 517-74 Hospitals, see also Health care facilities Disconnecting means, 517-72 Definition, 517-3 Equipment installations, 517-75 Essential electrical systems, 517-30 Patient care areas Guarding and grounding, 517-77 Overcurrent protection, 517-73 Definition, 517-3 Psychiatric Rating of supply conductors, 517-73 Definition, 517-3 Transformers and capacitors, 517-76 Hot tubs, see Spas and hot tubs Heat generating equipment, see Induc- Hotels and motels tion and dielectric heating equip- Lighting load, Table 220-3(b) ment Receptacle ground-fault circuit inter- Heat tape outlet, mobile home, 550-8(g) rupter protection, 210-8(b) Heater cords, see Cords, Heater Receptacle outlets required, guest rooms, 210-60 INDEX 70-895 Houseboats, see Floating buildings Motor-generator equipment, 665-C Hydromassage bathtubs, 680-G Other equipment, 665-D Definition, 680-4 Output, 665-44 Identification Induction heating Disconnecting means, 110-22 Definition, 665-2 Fire protective signaling circuits, 760-4 Inductive loads Flexible cords Motors, 430-83, 430-109 Grounded-conductor, 400-22 Signs, 600-2(b) Grounding-conductor, 400-23 Switches, types, ratings, 380-14 Grounded conductors, Art. 200 High leg, 215-8, 230-56, 384-3(e) Industrial machinery, Art. 670 Intrinsically safe systems, 504-80 Clearance, 670-5 Panelboard circuits, 384-13 Definition, 670-2 Service disconnecting means, 230-70 Nameplate data, 670-3 Ungrounded conductors, 210-4(d) Supply conductors and overcurrent protection, 670-4 Wiring device terminals, 250-119, 504-80 Infrared lamp heating appliances, 422-15 Identified Branch circuits, 210-23(c) and (d), Definition, Art. 100-A 424-3(a) Ex. Illumination, task Overcurrent protection, 422-27(c) Definition, 517-3 Inhalation anesthesizing location, see Immersible appliances, 422-24 Anesthesizing location Immersion heaters, cord- and plug- Inserts connected, 422-9 Cellular concrete floor raceways, 358-9 In sight from Cellular metal floor raceways, 356-10 Underfloor raceways, 354-14 Air-conditioning or refrigerating equipment, 440-14 Institutions, emergency lighting, Art. 700 Center pivot irrigation machines, Instructions, 110-3(b), 230-95(c) 675-8(b) Instrument transformers, see Transform- Definition, Art. 100-A ers, Instrument Duct heaters, 424-65 Electric-discharge lighting, 410-81(b) Instruments, meters, relays Fixed electric space heating equipment, Grounding, 250-L 424-19 Hazardous (classified) location, 501-3, 502-14 Motor driven appliances, 422-26 Motors, motor controllers, 430-102 Low-voltage, 517-64 Room air conditioners, 440-63 Insulation Signs, 600-2(a) Conductors, Art. 310 Incandescent lamps, Art. 410; see also Construction and application, 310-13 Hazardous (classified) locations Hazardous (classified) location, Class I, Guards 501-13 Aircraft hangars, 513-5(a) Identification, 310-12 Garages, 511-7(a) and (b) Line-type fire detectors, 760-55(b) Theater dressing rooms, 520-72 Marking, 310-11 Lamp wattage, marking on fixture, Motion picture projectors, 540-14 410-70 Theaters, 520-42 Meduim and mogul bases, 410-53 Double, see Double insulated Snap switches for, 380-14 Equipment, 110-3(a)(4) Fixture wire, 402-3 Independent Flexible cords, Table 400-4, 400-B Emergency lighting supply, 700-17 Heating cables, 424-E, 426-24 Supports, services, over buildings, Integrity, 110-7 230-29 Service conductors, 230-22, 230-30, Wiring, emergency circuits, 700-9 230-41 X-ray control, 660-24 Splices and joints, 110-14(b), 305-4(g), Individual branch circuits, see Branch 400-9, 530-12 circuits, individual Insulation levels Induced currents, metal enclosures, Definitions, Table 310-64 300-20, 334-12 Insulators, nonabsorbent, 230-27, 710-32 Induction and dielectric heating equip- Insulators, open wiring, see Open wiring ment, Art. 665 on insulators Definitions, 665-2 Integrated electrical systems, Art. 685 Guarding, grounding, and labeling, 665-B Orderly shutdown, 685-B 70-896 NATIONAL ELECTRICAL CODE Integrated gas spacer cable, Type IGS, Grounding, 504-50 Art. 325 Hazardous (classified locations), 500-2, Ampacity, 325-14 504-60 Bends, 325-11, 325-12 Identification, 504-80 Conductors, 325-20 Sealing, 504-70 Construction, 325-C Wiring methods, 504-20 Definition, 325-1 Introduction, Art. 90 Fittings, 325-13 Irons, see Flatirons Installation, 325-B Insulation, 325-21 Irrigation machines, Art. 675 Uses not permitted, 325-4 Bonding, 675-14 Uses permitted, 325-3 Center pivot Definition, 675-2 Interactive systems Center pivot irrigation machines, 675-B Definition, 690-2, 705-2 Collector rings, 675-11 Intercommunication systems, see Com- Conductors, 675-5, 675-9 munication circuits; Hazardous Control panel marking, 675-6 (classified) locations Current ratings, 675-7 Interconnected electric power produc- Definitions, 675-2 tion sources, Art. 705 Grounding, 675-12, 675-13 Irrigation cable, 675-4 Definitions, 705-2 Lightning protection, 675-15 Directory, 705-10 Motors on branch circuit, 675-10 Disconnect device, 705-22 Disconnecting means, equipment, 705-21 Isolated Disconnecting means, sources, 705-20 Arcing parts, 110-18 Ground-fault protection, 705-32 Definition, Art. 100-A Grounding, 705-50 Equipment grounding conductor, 250-74 Interrupting and withstand rating, 705-16 (FPN) Loss of primary source, 705-40 Phase installations, 300-5(i), Ex. 2 Output characteristics, 705-14 Power systems, 517-G, 517-64(c) Overcurrent protection, 705-30 Definition, 517-3 Point of connection, 705-12 Essential electrical systems, 517-30(c) Synchronous generators, 705-43 Grounding, 517-19(g) Unbalanced interconnections, 705-42 Installation, 517-160(a) Intermediate metal conduit, Art. 345 Location, 517-160(c)(5) Bends, 345-10, 345-11 Isolating means, over 600 volts, 710-22 Bushings, 345-15 Isolating switch, see Switch, Isolating Construction, 345-C Couplings and connectors, 345-9 Isolation by elevation Circuits over 600 volts, 110-34(e) Definition, 345-1 Circuits under 600 volts, 110-17 Number of conductors, 345-7 Reaming and threading, 345-8 Isolation transformer Size, 345-6 Definition, 517-3 Splices and taps, 345-14 Joints, see also Splices and taps Supports, 345-12 Expansion, see Expansion joints Uses permitted, 345-3 Grounding electrode conductor, 250-91(a) Wet locations, 345-5 Insulation, fixtures, 410-16(e) Intermittent duty Insulation of, 110-14(b) Definition, Art. 100-A Strain at, 400-10 Motors, 430-22(a) Ex. 1 Joists Interpretations, formal, see Formal inter- Air-handling, space, 300-22(c) Ex. 5 pretations Armored cable, 333-11 Ex. 2, 333-12 Interrupter switch, see Switches, Interrupter Boxes on, 370-23(a) and (d) Concealed knob-and-tube wiring, 324-11 Interrupting capacity, 110-9, 110-10, Electric space heating cables, 424-41(j) 240-60(c), 240-83(c) Holes through or notches in, 300-4(a) Interrupting rating, 110-9, 240-60(c), Nonmetallic sheathed cable, 336-12 240-83(c) Open wiring, crossing, 320-14 Definition, Art. 100-A Jumpers, bonding, 250-79 Intrinsically safe equipment, Art. 504 Circuit Bonding, 504-60 Definition, Art. 100-A Conductors, separation of, 504-30 Conduit joints, hazardous (classified) Definitions, 504-2 locations, 500-2 Equipment approval, 504-4 Equipment Equipment installation, 504-10 Definition, Art. 100-A INDEX 70-897 Expansion joints, telescoping sections of Heavy-duty, see Heavy-duty raceways, 250-77 lampholders Grounding-type receptacles, 250-74 Infrared lamps, 422-15 Hazardous (classified) locations, 501- Mogul base, see Mogul base lampholders 16(a), 502-16(b), 503-16 Outdoor, 225-25 Health care facilities, 517-19(c) and (d) Pendant Main Bathrooms, 410-4(d) Definition, Art. 100-A Not in clothes closets, 410-8(c) Piping systems, 250-80 Not in theater dressing rooms, 520-71 Service equipment, 250-72(d), 250-79(d) Screw-shell types for lamps only, 410-47 Junction boxes, see also Boxes; Pull Signs and outline lighting, 600-22 boxes Unswitched over combustible material, Accessibility, 370-29 410-6 Cellular concrete floor raceways, 358-7 Lamps, Art. 410; see also Lighting; Light- Cellular metal floor raceways, 356-9 ing fixtures; Hazardous (classified) Covers, 370-28(c) locations Deicing and snow-melting cables, 426-24 Arc, see Arc lamps Motor controllers and disconnects, Clothes closets, in, 410-8 430-10 Electric discharge, 410-P, 410-Q Nonheating cable leads, 424-43 Electric discharge, enclosure, 410-54 Separation from motors, 430-145(b) Fluorescent, see Fluorescent lighting Size fixture Conductors No. 4 and larger, 370-28 Guards, see Guarding and guards Conductors No. 6 and smaller, 370-16 Headlamps, see Handlamps Construction specifications, 370-C Incandescent, see Incandescent lamps Supports, 370-23 Infrared, see Infrared lamp heating Swimming pools, 680-21 appliances Switch enclosures, 373-8, 710-59 Motion picture projectors, 540-14, 540-20 Underfloor raceways, 354-13 Motion picture studios Kitchen equipment, commercial, 220-20 Film storage vaults, 530-51 Stages, 530-16, 530-17 Knife switches Viewing, cutting tables, 530-41 Connection, 380-6(c) Outdoor, location, 225-25 Construction specifications, 380-B Portable Enclosures, 380-3 Flexible cords for, 400-7 Position, 380-6 Motion picture studios, in, 530-16, Ratings, 380-13 530-17 Knob-and-tube wiring, Art. 324 Show windows, show cases, 400-11 Clearance Track-lamps, 410-105 Conductor, 324-8 Theaters Piping, exposed conductors, 324-10 Border and proscenium, 520-44 Conductor supports, 324-6 Dressing rooms, 520-72 Conductors, 324-5 Festoons, 520-65 Definition, 324-1 Footlights, 520-43 Splices, 324-12 Scene docks in, 520-47 Through walls, floors, etc., 324-9 Stage, arc, 520-61 Tie wires, 324-7 Switchboards, pilot lights, 520-53(g) Uses not permitted, 324-4 Wattage marking, flush and recessed Uses permitted, 324-3 fixtures, 410-70 Knockouts Laundry, outlets, dwellings, 210-50(c), Bonding service equipment, 250-72(d) 210-52(f), 220-4(c) Openings to be closed, 110-12, 370-7, 370-8, 373-4 Laundry area, mobile home parks Definition, 550-2 Labeled Definition, Art. 100-A Legally required standby systems, Art. 701 Labels required, 551-47(q)(3), 551-47(r)(4) Capacity and rating, 701-6 Lacquers and paints Circuit wiring, 701-B Application, Art. 516 Overcurrent protection, 701-D Atmospheres, 500-3, 500-5, Art. 501 Signals, 701-8 Lampholders Signs, 701-9 Branch circuits supplying, 210-23 Sources or power, 701-C Circuits less than 50 volts, 720-5 Tests and maintenance, 701-5 Construction, 410-J Transfer equipment, 701-7 Damp or wet locations, 410-4(a), 410-49 Lengths Double-pole switched, 410-48 Busways used as branch circuits, 364-14 70-898 NATIONAL ELECTRICAL CODE Free conductors at outlets and switches, Electric discharge, see Electric discharge 300-14, 424-43, 426-23, 550-10(h) lighting Intermediate metal conduit, 345-16(a) Fluorescent, see Fluorescent lighting Nonmetallic flexible tubing with open fixtures wiring, 320-10 Flush, 410-M, 410-N Nonmetallic rigid metal conduit, 347-17 Fountains, 680-51 Pull and junction boxes, 370-28, 370-71 Grounding, 410-E Rigid metal conduit, 346-15(a) Live parts, 410-3 Space heating cable, nonheating leads, Location, 410-B 424-34 Motion picture studios, Art. 530 Taps, 210-19, 240-21 Mounting, 410-76, 410-77 10-ft. rule, 240-21 Ex. 2 No-niche, 680-20(d) 25-ft. rule, 240-21 Ex. 3 Definition, 680-4 25-ft. rule, transformers, 240-21 Ex. 8 Outdoors, 410-4(a) 100-ft. rule, 240-21 Ex. 10 Outlets required, 210-70 Motor feeders, 430-28, 430-53(d) Overcurrent protection, wires and cords, 240-4 Life safety branch Polarization, 410-23 Definition, 517-3 Raceways, 410-31 Essential electrical systems, 517-32, Recessed, see Recessed lighting fixtures 517-42 Recreational vehicles, 551-53 Life support equipment, electrical Show windows, 410-7 Definition, 517-3 Spas and hot tubs, 680-41(b) Supports, 410-D Lighting Swimming pools, 680-20, 680-32 Branch circuits, calculation of load, Theaters, Art. 520 220-3(b) Wet, 410-4 Cove, 410-9 Wet-niche, 680-20(b) Electric discharge, see Electric discharge Definition, 680-4 lighting Wiring, 410-F Emergency, Art. 700 Lighting outlets, 210-70 Feeders, calculation of load, 220-10(a), 220-30 Lightning rods Festoon, see Festoon lighting As a ground, 250-86 Fixtures, see Lighting fixtures Irrigation machines, 675-15 Outlets, 210-70 Spacing from, 250-46 Outline, see Outline lighting Lightning (surge) arresters, Art. 280 Track, 220-3(c)(6) 410-R Antenna discharge units, 810-20 Connections at services, 230-82 Ex. 4 Lighting assembly, cord- and plug- Grounding, 250-46, 250-86, 280-25 connected, 680-56 Radio and television equipment Definition, 680-4 Receiving stations (antenna discharge Lighting fixtures, Art. 410; see also Hazunits), 810-20 ardous (classified) locations Transmitting stations, 810-57 Arc, 520-61, 530-17 Services over 600 volts, 230-209 Autotransformers Lightning (surge) protection, Art. 280 Ballasts supplying fluorescent fixtures, Communication circuit conductors, 410-78 800-13 Supply circuits, 210-9 Hazardous (classified) locations, 501-17, Auxiliary equipment, 410-77 502-17 Boxes, canopies, pans, 410-C Lights, see also Lamps; Lighting Branch circuits Border, cables for, theaters, 520-44(b) Computation of, 220-3(a), (b), and (c) From railway conductors, 110-19 Sizes, 210-22, 210-23 Scenery, theaters, halls, 520-63 Voltages, 210-6, 410-73 Clothes closets, 410-8 Limited care facility Definition, 410-8(a) Definition, 517-3 Combustible material, near, 410-5, 410-76 Line isolation monitor, 517-160(b) Connection, fluorescent, 410-14, 410-30 Definition, 517-3 Construction, 410-M, 410-N Lint, flyings, Art. 503 Corrosive, 410-4(b) Liquidtight flexible metal conduit, 351-A Damp, wet, or corrosive locations, Bends, 351-10 410-4, 410-49 Definition, 351-2 Dry-niche, 680-20(e) Fittings, 351-7 Definition, 680-4 Grounding, 351-9 Ducts or hoods, in, 410-4(c) Number of conductors in, 351-6 INDEX 70-899 Size, 351-5 Generators, 445-2 Supports, 351-8 Grounding connections at electrodes, Use, 351-4 250-112 Liquidtight flexible nonmetallic conduit, Hazardous, see Hazardous (classified) 351-B locations Bends, 351-30 Junction boxes, 370-19 Definition, 351-22 Lamps, outdoors, 225-25 Fittings, 351-26 Lighting fixtures, 410-B Grounding, 351-27 Mobile homes disconnecting means and Number of conductors in, 351-25 branch-circuit protective equip- Size, 351-24 ment, 550-6 Splices and taps, 351-29 Motion picture projection equipment, 540-11 Supports, 351-27 Use, 351-23 Motor disconnecting means, 430-102 Motor feeder taps, 430-28 Listed Motors, 430-14 Definition, Art. 100-A Overcurrent devices, 240-B Live parts, see also Enclosures; Energized Panelboards, 384-17 parts; Guarding Protective devices for communication Appliances, 422-D circuits, 800-30 Capacitors, 460-2 Recreational vehicle disconnecting means Exposed, 110-16 and distribution panelboard, Generators, 445-6 551-13(b) Guarding, 110-17 Resistors and reactors, 470-2 Hazardous (classified) locations, 501-15, Service disconnecting means, 230-70(a), 502-15, 503-15 230-72(c) In theaters, 520-6 Service heads, 230-54 Lamp terminals and lampholders, 410-82 Service overcurrent protection, 230-91, Lighting fixtures, lampholders, lamps, 230-92 receptacles, 410-3, 410-46 Sign switches, 600-2(a) Lighting systems, electric discharge, Splices and taps 410-P, 410-Q Auxiliary gutters, 374-8(a) Transformers, guarding, 450-8 Wireways, 362-7 Surge arresters, 280-11 Loads Swimming pool junction box and trans- Appliances, household cooking, demand former enclosures, 680-21 table, 220-19 Switchboards, 384-5 thru 384-7 Branch circuits Switches, 380-4 Calculations, Art. 220, Chap. 9 Part B System grounding connections, 250-C Maximum, 210-22, Table 210-24 Transformers and vaults, 450-1, 450-13 Mobile homes, 550-13 Ventilation openings for transformer Permissible, 210-23, Table 210-24 vaults, 450-45(a) Continuous, see Continuous loads Wet, see Wet locations and Damp or wet Demand locations Clothes dryers, 220-18 Household cooking appliances, 220-19 Locked rotor motor current Farm, 220-40 Code letters, 430-7(b), Table 430-7(b) Feeder, 220-B, Chap. 9 Part B Conversion, Table 430-151 Calculations, Art. 220 Hermetic refrigerant motor-compressors, Inductive, see Inductive loads 440-3(a) Mobile home parks, 550-22 Locknuts, double, where required Mobile homes, 550-13 Hazardous (classified) locations, Motors, conductors, 430-B 501-16(a) Stage equipment, circuit loads, 520-41 Mobile homes, 550-10(f) Locations Over 250 volts to ground, 250-76 Capacitors, 460-2(a) Recreational vehicles, 551-47(b) Crane and hoist disconnecting means, Wholly insulated bushings used, 373-6(c) 610-D Low-voltage circuits, see also Remote- Damp or wet, see Damp or wet locations control, signaling, and power- Definition, Art. 100-A limited circuits Dry, see Dry locations Definition, 551-2 Electric discharge lighting transformers, Less than 50 volts, Art. 720 over 1000 volts, 410-86 Elevator motor disconnecting means, Low-voltage equipment and instruments 620-51(b) Definition, 517-2 Foreign pipes, accessories, transformer Lugs vaults, 450-47 Connection of service conductors, 230-81 70-900 NATIONAL ELECTRICAL CODE Connection to terminals, 110-14(a) Metal working machine tools and plastic Solderless type at electrodes, 250-115 machinery, see Industrial machinery Machine tools, see Industrial machinery Metal-clad cable, Art. 334 Made electrodes, 250-83 Ampacity, 334-13 Mandatory rules, 90-5 Bends, 334-11 Conductors, 334-20 Manholes, 300-32 Ex. 2, 725-15 Ex. 2 Construction, 334-C Manufactured buildings, Art. 545 Definition, 334-1 Bonding and grounding, 545-11 Fittings for, 334-12 Boxes, 545-9 Grounding, 334-23 Component interconnections, 545-13 Installation, 334-B Definitions, 545-3 Marking, 310-11(b)(2) Ex. 3, 334-24 Grounding electrode conductor, 545-12 Supports, 334-10 Protection of conductors and equipment, Through studs, joists, and rafters, 545-8 300-4(a) Receptacle or switch with integral enclo- Uses not permitted, 334-3 sure, 545-10 Uses permitted, 334-3 Service-entrance conductors, 545-5, Voltages, 334-2 545-6 Service equipment location, 545-7 Metal-enclosed switchgear, see Wiring methods, 545-4 Switchgear, metal-enclosed Manufactured wiring systems, Art. 604 Metals Construction, 604-6 Dissimilar, 110-14, 250-115, 345-3(a), Definition, 604-2 346-1(b), 348-1 Unused outlets, 604-7 Ferrous, see Ferrous metals Uses not permitted, 604-5 Meter socket enclosures, 373-1; see also Uses permitted, 604-4 Cabinets, cutout boxes, and meter Marinas and boatyards, Art. 555 socket enclosures Feeders and services, 555-5 Meters Gasoline dispensing stations, 555-9 Connection and location at services, Grounding, 555-7 230-82 Ex. 3, 230-94 Ex. 5 Receptacles, 555-3 Branch circuits for, 555-4 Grounding of cases, 250-123, 250-124 Wiring methods for, 555-6 Grounding to circuit connector, 250-61(b) Ex. 3 Over and under navigable water, 555-8 Hazardous (classified) locations, 501-3, Markings, see articles on wiring and 502-14 equipment involved Metric units of measurement, 90-9 Means of egress Health care facilities, 517-32(a) Mineral-insulated metal-sheathed Illumination, 517-32(a), 517-42(a) cable, Type MI, Art. 330 Mechanical execution of work, 110-12 Bends, 330-13 Medium voltage cable, Type MV, Construction specifications, 330-C Art. 326 Definition, 330-1 Ampacity, 326-6 Fittings, 330-14 Construction, 326-5 Supports, 330-12 Definition, 326-1 Terminating seals, 330-15 Marking, 326-7 Through or parallel to studs, joists, or Uses not permitted, 326-4 metal rafters, 300-4, 330-11 Uses permitted, 326-3 Uses not permitted, 330-4 Uses permitted, 330-3 Messenger supported wiring, Art. 321 Definition, 321-1 Wet locations, 300-6(c), 330-10 Messenger support, 321-6 Mobile home parks, Art. 550 Splices and taps, 321-8 Definitions, 550-2 Uses not permitted, 321-4 Distribution system, 550-21 Uses permitted, 321-3 Electrical wiring system Metal frame of building Feeder and service demand factors, Grounding electrode, 250-81(b) 550-5, 550-C, Table 550-22 Not permitted as equipment grounding Minimum allowable demand factor, conductor, 250-58(a) 550-22 Metal hood, stage switchboard, see Mobile home service equipment, Hood, Metal 550-23(a) Metal outlet boxes, see Boxes, Metallic Mobile homes, Art. 550 Accessory buildings or structures Metal siding, grounding of, 250-44 (FPN) Definition, 550-2 Metal wireways, see Wireways, metal Appliances, 550-9 INDEX 70-901 Branch circuit protective equipment, Circuits, 430-B 550-6(b) Code letters, Table 430-7(b) Branch circuits, 550-7 Coded and noncoded, setting of branch Calculations of loads, 550-13 circuit devices, Table 430-152 Communications circuits, 800-41 Combined overcurrent protection, 430-55 Definitions, 550-2 Conductors, 430-B Disconnecting means, 550-6(a) Control circuits, 430-F Expandable and dual units, wiring, Controllers, see Controllers, Motor 550-14 Current, full load, see Full load current Fixtures, 550-9 motors General requirements, 550-4 Curtain, theater, 520-48 Ground-fault circuit interrupter, 550-8(b) Disconnecting means, 430-H Grounding, 550-11 Energized parts protection, 430-K Heat tape outlet, 550-8(g) Feeder demand factor, 430-26 Insulated neutral required, 550-11(a) Feeders, calculation of load, 220-10, Nameplates, 550-6(d) 220-30 Outdoor outlets, fixtures, air-cooling Full-load current, see Full-load current equipment, 550-15 motors Power supply, 550-5 Fuseholder, size of, 430-57 Receptacle outlets, 550-8 General, 430-A Service equipment Ground-fault protection, 430-D, 430-E Definition, 550-2 Grounding, 250-E, 430-L Testing, 550-12 Grouped, 430-24, 430-42, 430-53, 430-87, Wiring methods and materials, 550-10 430-112 Mobile X-ray equipment, 660-4(b) Guarding, 430-133 Definition, 660-2 Hazardous (classified) locations, 501-8, Module, solar voltaic systems 502-8, 503-6 Definition, 690-2 Highest-rated or smallest-rated, 430-17 Mogul base lampholders, 210-6, 410-53 Industrial machinery, Art. 670 Liquids, protection from, 430-11 Monorails, Art. 610 Location, 430-14 Motion picture and television studios, Maintenance, 430-14 Art. 530 Marking, 430-7 Definitions, 530-2 Terminals, 430-9(a) Dressing rooms, 530-C Motor control centers, 430-H Feeder conductors, sizing, 530-19 Multispeed, see Multispeed motors Film storage vault, 530-E Over 600 volts, 430-J Grounding, 530-20 Overcurrent protection, 430-C Lamps, 530-16, 530-17 Overheating, dust accumulations, 430-16 Live parts, 530-15 Overload protection, 430-C Overcurrent protection, 530-18 Part winding, see Part winding motors Stage or set, 530-B Restarting, automatic, 430-43 Substations, 530-F Short circuit protection, 430-D, 430-E Wiring, 530-11, 530-12 Starting, shunting, 430-35 Motion picture projectors, see Projectors, Tables, 430-M Motion picture Terminal housings, size, 430-12 Motion picture theaters, see Theaters Terminals, 430-9 Motor home Three running overload units, Table Definition, 551-2 430-37 Motor-circuit switches, see Switches, Ultimate trip current, 430-32(a)(2) Motor-circuit Ventilation, 430-14(a) Welders, arc, motor-generator, 630-C Motor-generator arc welders, 630-C Wiring diagram, Diagram 430-1 Motors, Art. 430 Wiring space in enclosures, 430-10 Air conditioning units, Art. 440 Mounting of equipment, 110-13, 300-11, Appliances, motor driven, 430-H 370-23, 380-10(b), 410-D Branch circuits, 430-B Combination loads, 430-25, 430-63 Moving walks, see Elevators, dumbwait- Continuous duty, 430-22 ers, escalators, moving walks, Intermittent duty, 430-22 wheelchair lifts, and stairway chair lifts Several motors, 430-24 Single motor, 430-22 Multioutlet assembly, Art. 353 Taps, 430-28 Ex., 430-53 Calculation of load, 220-3(c) Torque motors, 430-52(b) Definition, Art. 100-A Wound rotor secondary, 430-23 Metal, through dry partitions, 353-3 Capacitor, 460-8, 460-9 Use, 353-2 70-902 NATIONAL ELECTRICAL CODE Multiple circuit connections, grounding, Uses not permitted, 342-4 250-62 Uses permitted, 342-3 Multiple conductors (conductors in par- Nonmetallic pipelines, 427-23 allel), see Conductors, Multiple Nonmetallic rigid conduit, see Rigid non- Multiple fuses (fuses in parallel), 240-8, metallic conduit 380-17 Definition, 100-B Nonmetallic wireways, see Wireways, nonmetallic Multispeed motors Nonmetallic-sheathed cable, 300-4(b), Branch circuits, 430-22(a) Art. 336 Locked-rotor code letters, 430-7(b) Accessible attics, 336-13 Marking, 430-7 Bends, 336-14 Overload protection, 430-32(a) and (c) Conductors, 336-26 Multiwire branch circuit, 210-4 Construction, 336-C Definition, Art. 100-A Definition, 336-1 Nameplates, see articles on wiring and Devices with integral enclosures, 336-18 equipment involved Exposed work, 336-10 Neat and workmanlike installation, Installation, 336-B 110-12 Insulating devices, 336-16 Marking, 336-27 Neutral, see also Conductors, Grounded Nonmetallic outlet boxes, 336-17 Bare, 230-22 Ex., 230-30 Ex., 230-41 Ex. Supports, 336-15 Bonding to service equipment, 250-72(a) Common, see Common neutral Three floor limitation, 336-4(a)(1) Conductor, Art. 310 Notes 3 and 10 of Through or parallel to studs, joists, Ampacity Tables 0-2000 volts, rafters, 300-4(a), 336-11 Tables B-310-1 thru B-310-10 Unfinished basements, 336-12 Continuity of, 300-13 Uses not permitted, 336-4 Definition, Art. 100-A Uses permitted, 336-3 Equipment, grounding to, 250-61 Nontamperable Feeder load, 220-22 Circuit breakers, 240-82-- Grounding of Type S fuses, 240-54(d) AC systems, 250-5, 250-25, 250-26 DC systems, 250-3, 250-22 Number of services, 230-2 Identification, Art. 200 Nurses' stations Ranges and dryers, grounding, 250-60 Definition, 517-3 Uninsulated, where permitted, 230-22 Nursing homes Ex., 230-30 Ex., 230-41 Ex., Definition, 517-3 250-60(c), 338-3(b) Essential electrical systems, 517-40 Nightclubs, Art. 518 Occupancy, lighting loads, Table Nipples, conduit, see Conduit nipples 220-3(b), 220-3(c) Noise, see Electrical noise Office furnishings, Art. 605 Nonautomatic General, 605-2 Definition, Art. 100-A Lighting, 605-5 Partitions Nonelectrical equipment, grounding, 250-44 Interconnections, 605-4 Fixed-type, 605-6 Nongrounding-type receptacles, replace- Freestanding type, 506-7, 506-8 ments, see Receptacles, Wireways, 605-3 Nongrounding type Official interpretations, see Formal inter- Nonincentive circuit pretations Definition, 100-A Oil (filled) cutout Nonmetallic boxes, see Boxes, Nonmetallic Definition, 100-B Nonmetallic conduit, preassembled Open wiring on insulators, Art. 320 cable in, see Preassembled cable in Accessible attics, 320-15 nonmetallic conduit Ampacity, 320-5(b) Nonmetallic extensions, Art. 342 Conductors, types permitted, 320-5(a) Definition, 342-1 Definition, 320-1 Fittings, 342-6 Drip loops, 320-13 Installation Flexible nonmetallic tubing, 320-10 As aerial cable, 342-7(b) Passing through walls and floors, 320-11 As surface extensions, 342-7(a) Separation from metal work and piping, Marking, 342-8 320-12 Splices and taps, 342-5 Supports, 320-6, 320-7 INDEX 70-903 Switches, 320-16 Power Tie wires, 320-8 Definition, Art. 100-A Use permitted, 320-3 Receptacle Openings in equipment to be closed, Definition, Art. 100-A 110-12(a), 370-8, 373-4 Required, 210-C Rooftop heating, air-conditioning, and Operable, externally refrigeration equipment, 210-63 Definition, Art. 100-A Outline lighting, Art. 600 Operating rooms, hospital, 517-D Definition, Art. 100-A Emergency lighting system, Art. 700 Grounding, conductor size, 250-97 Optical fiber cables, Art. 770 Output circuits Access to electrical equipment, 770-7 Amplifiers, 640-5 Cable trays, 770-6 Heat generating equipment, 665-44, Cables 665-64 Application, 770-53 Marking, 770-50 Outside branch circuits and feeders, Substitutions, 770-53 Art. 225 Definition, 770-3 Calculation of load Fire resistance of, 770-49 Branch circuits, 220-3, 225-3(a) Grounding of entrance cables, 770-33 Feeders, 220-B, 225-3(b) Installation, 770-50, 770-52 Circuit entrances and exits, buildings, Listing requirements, 770-50, 770-51 225-11(c) Location, 770-2 Conductors Marking, 770-50 Clearance Optical fibers and electrical conductors, From buildings, 225-19 770-52 From ground, 225-18 Raceway system, 770-5 Covering, 225-4 Types, 770-4, 770-6, 770-51 Size, 225-5, 225-6 Within buildings, 770-C Disconnection, 225-8 Festoon supports, 225-13 Optional standby systems, Art. 702 Lighting equipment on poles or other Capacity and rating, 702-5 structures, 225-7 Circuit wiring, 702-B Location of outdoor lamps, 225-25 Definition, 702-2 Mechanical protection, 225-20 Equipment approval, 702-3 More than one building or structure, Signals, 702-7 225-11 Signs, 702-8 Outdoor lampholders, 225-24, 225-25 Transfer equipment, 702-6 Overcurrent protection, 225-9 Organs Point of attachment, 225-16 Electronic, 640-1 Spacing, open conductors, 225-14 Pipe, Art. 650 Supports Conductors, 650-5, 650-6 Festoons, 225-13 Grounding, 650-4 Open conductors, 225-12 Installation of conductors, 650-6 Over buildings, 225-15 Overcurrent protection, 650-7 Vegetation, live, 225-26 Source of energy, 650-3 Wiring on buildings, 225-10 Outdoor receptacles, 210-8(a)(3), Outside of buildings, when services 210-52(e), 410-57, 550-8(e), 680-6 considered, 230-6 Outlet boxes, see Boxes, Outlet Ovens, wall-mounted, see also Cooking Outlet spacing, dwelling baseboard units; Ranges Branch circuits, 210-19, 210-23 heaters, 210-52(a) Ex. Connections, 422-17 Outlets Definition, Art. 100-A Appliance, 210-50(c) Demand loads, Table 220-19 Definition, Art. 100-A Grounding, 250-57, 250-60 Devices, branch circuits, 210-7 Over 600 volts, Art. 710 Discontinued Ampacity, 310-15, 318-13 Cellular concrete floor raceways, Binding, 300-34 358-13 Boxes, pull and junction, 370-D Cellular metal floor raceways, 356-7 Busways, 364-B Underfloor raceways, 354-7 Capacitors, 460-B Laundry, 210-52(f), 220-3(c) Circuit conductors, 710-32 Lighting, 210-70 Circuit interrupting devices, 710-21 Definition, Art. 100-A Conductors, 110-B, 710-5 Multioutlet assembly, see Multioutlet Definition, Art. 100-B assembly Electrode type boilers, 710-G 70-904 NATIONAL ELECTRICAL CODE Elevation of unguarded live parts, Fuses and fuseholders, 240-8, 240-E, 110-34(e) 240-F Enclosure for electrical installations, Generators, 445-4 110-31 Grounded conductor, 240-22 Equipment, 710-B, 710-C Induction and dielectric heating equip- Grounding, 300-36, 710-7 ment, 665-42 Headroom above working spaces, 110-32 Installation, 240-A Illumination of working spaces, 110-34(d) Interconnected electric power production Indoor installations, 710-11 sources, 705-30 Insulation shielding, 710-6 Legally required standby systems, 701-D Isolating means, 710-22 Lighting track, 410-103 Metal-enclosed equipment, 710-13, Location, 230-91, 240-B 710-24 Mobile home, 550-6 Mobile and portable equipment, 710-E Motion picture and television studios, Moisture, mechanical protection, metal- 530-18, 530-63 sheathed cables, 710-8 Motors, motor circuits, controllers, Oil-filled cutouts, 710-21(d) 430-C, 430-D Outdoor installations, 710-12 Control circuits, 430-72 Overcurrent protection, 240-H, 710-20 Over 600 volts, 430-124, 430-125 Protection of equipment, 710-9 Multiple fuses and circuit breakers (in Resistors and reactors, 470-B parallel), 240-8, 380-17 Separation, 384-36, 710-33 Occupant access to, 240-24(b) Services, 230-H Organs, 650-7 Shielding solid dielectric-insulated con- Outside branch circuits and feeders, ductors, 310-6 225-9 Temporary, 305-5 Over 600 volts, 240-H, 460-25, 710-20, Tray installations, Art. 318 710-42, 710-52 Tunnel installation, 710-F Panelboards, 384-15; 384-16 Voltage regulators, 710-23 Paralleled fuses and circuit breakers, Wiring methods, 300-B, 710-4 240-8, 380-17 Overcurrent Recreational vehicles, 551-10(e), 551-43, 551-45 Definition, Art. 100-A Remote-control circuits, 240-3 Ex. 1, Devices, standard, 240-6 Art. 725 Overcurrent protection, Art. 240 Services Air-conditioning and refrigerating equip- Entrance conductor, 230-G ment, 440-C Over 600 volts, 230-208 Appliances, 422-28 Single appliance, 210-20 Branch circuits, 210-20 Solar photovoltaic systems, 690-9 Busways, 364-9 thru 364-13 Sound recording equipment, 640-10 Capacitors, 460-8(b) Supplementary, 240-10 Circuit breakers, 240-8, 240-G Switchboards, 384-2 Circuits less than 50 volts, 720-8 Television studios, see Motion picture Circuits, remote control, signaling, and and television studios power-limited Theaters, stage switchboards, 520-23, Class 1 systems, 725-12 520-25(a), 520-52, 520-53, 520-62 Class 2 and Class 3 systems, 725-35, Transformers, 450-3 thru 450-5 725-36 Vertical position, enclosures, 240-33 Communications systems, 800-12, Welders, 630-12, 630-32 800-13, 800-C, 800-D X-ray equipment, 517-73, 660-6 Cords, flexible and tinsel, 240-4, 400-13 Overhead spans, 225-6(a) Cranes and hoists, 610-E Overload Current-limiting Definition, 240-11 Definition, Art. 100-A Disconnecting and guarding, 240-D Panel, solar photovoltaic systems Electric space heating equipment, 424-22 Definition, 690-2 Electroplating systems, 669-9 Panelboards, Art. 384, see also Hazard- Elevators, dumbwaiters, escalators, movous (classified) locations ing walks, wheelchair lifts, stairway Bonding, 517-14 chair lifts, 620-G Component parts, 384-33 Emergency systems, 700-F Damp or wet locations, 384-17 Enclosures, 240-C Definition, Art. 100-A Feeder taps, 240-21, 430-28 Distribution Fire protective signaling systems, 760-12, Definition, Art. 100-A, 551-2 760-13, 760-23, 760-24 Enclosure, 384-18 Fixture wires, 240-4, 402-12 General, 384-13 Flexible cords, see Cords, Flexible Grounding, 384-20, 517-19(d) INDEX 70-905 Health care facilities, 517-14, 517-19(d) Definition, 455-2 Lighting and appliance branch-circuit Different types of, 455-B Definition, 384-14 Disconnecting means, 455-8, 455-20 Number of overcurrent devices, 384-15 Grounding, 455-5 Overcurrent protection, 384-16 Marking, 455-4 Relative arrangement of switches and Overcurrent protection, 455-7 fuses, 384-19 Power interruption, 455-22 Service equipment, 230-G, 230-H, 384- Terminal housings, 455-10 3(c), 384-16(a) Photovoltaic systems, see Solar Spacing, minimum, 384-36 photovoltaic systems Support for busbars and conductors, 384-3 Physical damage, see Protection, Physi- Use as junction boxes, etc., 373-8 cal damage Wire bending space, 384-35 Pipe, gas, see Gas pipe Pans, fixture, 410-13 Pipe electrodes, 250-83(c) Paralleled Pipe organs, see Organs, Pipe Alternate sources, 230-83 Ex. 2, Art. 705 Pipeline Elevators, dumbwaiters, escalators, mov- Definition, 427-2 ing walks, 620-12(a)(1) Ex. Piping systems, bonding, 250-80 Power production sources, Art. 705 Places of assembly, see Assembly, Paralleled circuit breakers and fuses, places of see Fuses, In parallel Plants Paralleled conductors, see Conductors, Bulk storage, Art. 515 Parallel Cleaning and dyeing, 500-4, Art. 501 Parts, see specific type such as Live parts Clothing manufacturing, 500-6, Art. 503 Part-winding motors, 430-3 Woodworking, 500-6, Art. 503 Code letter markings, 430-7(b)(5) Plate electrodes, 250-83(d) Patching tables, motion picture, 530-D Plenums, 300-22 Path, grounding, 250-51, 250-53 Definition, Art. 100-A Wiring in, 300-22 Patient bed location Definition, 517-3 Pliable raceways, see Raceways, Pliable Plugging boxes, motion picture studios, Patient care areas, 517-13(a), 517-80; see 530-14, 530-18(d) also Health care facilities Definition, 530-3 Definition, 517-3 Plugs, attachment, see Attachment plugs Patient vicinity Definition, 517-3 Polarity identification Conductors, 310-12(a) Pediatric and psychiatric locations, Systems and circuits, Art. 200 517-18(c) Polarization Pendant conductors, lamps, 410-27 Appliances, 422-23 Pendants Lighting fixtures, 410-23 Aircraft hangars, 513-4(b) Plugs, receptacles, and connectors, Anesthetizing locations, 517-61(b)(3) 200-10(c) Ex. 2, 517-61(c)(1) Ex. Portable handlamps, 410-42(a) Bathrooms, 410-4(d) Receptacle adapters, 410-58(b)(3) Clothes closets, 410-8(c) Screw-shell type lampholders, 410-47 Dressing rooms, theater, 520-71 Poles Flexible cord, 400-7(a) Climbing space, conductors, 225-14(d) Garages, commercial, 511-6(b) Conductors, mechanical protection, Mobile homes, 550-9(c) 225-20, 230-50(b), 230-51 Receptacle cord, 210-50(a) Supporting lighting fixtures, 410-15(b) Periodic duty Pool cover, see Covers, Pool, Electrically Definition, Art. 100-A operated Permanent plaque or directory, 230-2, Pools, see also Swimming pools, foun- 705-10 tains, and similar installations Definition, 680-4 Permission, special Definition, Art. 100-A Portable appliances, see Appliances Portable equipment Person, qualified Definition, 530-3 Definition, Art. 100-A Disconnecting means, 517-72(c) Phase converters, Art. 455 Double insulation, 250-45 Capacitors, 455-10 Generators, 250-6 Conductors, 455-6 Grounding, 250-45, 250-59 70-906 NATIONAL ELECTRICAL CODE Grounding, conductor size, 250-95 Projectors, motion picture, 520-2, Art. X-ray, 600-4(b) 540 Definition, 660-2 Definitions, 540-B Portable handlamps, see Handlamps, Grounding, 250-43(h) Portable Protection Portable lamps, 410-42, 410-105, 516-3(d), Combustible material, appliances, 422-10 530-16, see also Lamps, Portable Corrosion Portable stage equipment, see Stage Boxes, metal, 370-40, 370-72 equipment, Portable Conductors, 310-9 Portable switchboards, see Switch- Electrical metallic tubing, 348-1 boards, Portable General equipment, 300-6 Intermediate metal conduit, 345-3 Portable wiring, motion picture studios, Metal-clad cable, 334-4 530-12 MI cable, 330-3, 330-4 Positive-pressure ventilation, see Venti- Nometallic sheathed cable, 336-4(b) lation, Positive-pressure Rigid metal conduit, 346-1 Potheads, 230-202(f) Underfloor raceways, 354-2 Power, emergency systems, see Emer- Liquids, motors, 430-11 gency systems Live parts, 110-17, 445-6, 450-8(c) and (d) Motor overload, 430-C Power and control tray cable, Type TC, Overcurrent, see Overcurrent protection Art. 340 Physical damage Ampacity, 340-7 Armored cable, 333-6 Bends, 340-8 Construction, 340-3 Busways, 364-4(b) Definition, 340-1 Conductors, 300-4, 710-3(b)(1) Marking, 340-6 Electrical metallic tubing, 348-1 Uses not permitted, 340-5 Electrical nonmetallic tubing, 331-4 Uses permitted, 340-4 Lamps, electric discharge lighting, 410-90 Power conditioning unit, solar Lighting track, 410-101(c) photovoltaic systems Liquidtight flexible metal conduit, Definition, 690-2 351-4(b)(1) Output circuit Definition, 690-2 Liquidtight flexible nonmetallic conduit, 351-23(b)(1) Power outlet, see Outlets, Power Metal-clad cable, 334-3 Power production sources, see Intercon- Mineral-insulated metal-sheathed cable, nected electric power production 330-3 sources Multioutlet assembly, 353-2 Power source, alternate Nonmetallic-sheathed cable, 336-4 Definition, 517-3 Open conductors and cables, 230-50(b) Power supply, mobile homes, 550-5 Open wiring, 320-10, 320-14 Overcurrent devices, 240-24(c) Power supply assembly, recreational Raceways, 300-5(d), 710-3(b) vehicles, 551-42(d) Recreational vehicle park underground Definition, 551-2 branch circuits and feeders, Power-limited tray cable, Type PLTC 551-80(b) Class I, Division 2 locations, 501-4(b) Resistors and reactors, 470-3 Class 3 circuits, 725-51(e) Rigid nonmetallic conduit, 347-3(c) Marking, 310-11 Shielded nonmetallic sheathed cable, Preassembled cable in nonmetallic 337-5 conduit, Art. 343 Space heating systems, 424-12 Construction, 343-C Surface raceways, 352-1, 352-22 Description, 343-1 Transformers, 450-8(a) Installation, 343-B UF cable, 339-3(a)(3) Use, 343-3, 343-4 Underground installations, 230-49, Premises wiring (system) 300-5(d) Definition, Art. 100-A Wireways, 362-2 Pressure connector, see Connector, Protective devices, see Circuit breakers; Pressure Fuses; Overcurrent protection; Prevention of fire spread, see Fire spread Thermal cutouts through walls, floors, etc. Protective equipment, see Guarding and Programmed power distribution, see guards Closed-loop and programmed Public address systems, Art. 640 power distribution Emergency lighting systems, 700-1 (FPN 3) INDEX 70-907 Public assembly places, Art. 518 Underground, 300-5(c) Emergency lighting system, Art. 700 Wireways, see Wireways Pull boxes, see also Boxes; Junction Wiring, exterior surfaces of buildings, boxes 225-22 Accessibility, 370-29 Radio and television equipment, Art. Construction specifications, 370-C, 370-72 810; see also Community antenna television and radio distribution Sizes No. 4 and larger conductors, 370-28 system No. 6 and smaller conductors, Amateur transmitting and receiving sta- 370-16(c) tions, 810-C Over 600 volts, 370-71 Interior installation - transmitting stations, 810-D Pumps, floating lake, 680-H Receiving equipment - antenna systems, Qualified person, see Person, Qualified 810-B Raceways Radiographic equipment, 660-23(a) Bonding, 230-63, 250-G, 501-16(a), 502-16(a), 503-16(a) Railway conductors, power and light, Busways, see Busways 110-19 Cellular concrete floor, see Cellular con- Rainproof crete floor raceways Definition, Art. 100-A Cellular metal floor, see Cellular metal floor raceways Raintight Conductors in service, 230-7 Definition, Art. 100-A Continuity, 300-10, 300-12 Ranges, 422-17, 422-22(b), see also Cook- Definition, Art. 100-A ing units; Ovens Drainage, 225-22, 230-53, 230-202(g) Branch circuits Electrical metallic tubing, see Electrical Calculation of load, Table 220-19 metallic tubing Conductors, 210-19 Emergency circuits, independent, 700-9 Expansion joints, 250-77, 300-7(b), 347-9 Maximum load, 210-22 Exposed to different temperatures, 300-7 Feeders; calculation of load, 220-10(a), Fixtures as, 410-31 220-30 Flexible metal conduit, see Flexible Grounding, 250-60 metal conduit Loads, demand, Table 220-19 Flexible metallic tubing, see Flexible Receptacles, 210-7, 250-60(d) metallic tubing Grounding, 250-D, 250-56 Rated load current, 440-4(a) Definition 440-2 Short sections, 250-33 Ex. 2, 250-56 Induced currents, 300-20 Reactors, see Resistors and reactors Insulating bushings, 300-16, 373-6(c) Readily accessible, see Accessible, Intermediate metal conduit, see Interme- Readily diate metal conduit Liquidtight flexible metal conduit, see Reaming, ends of metal conduits, 345-8, Liquidtight flexible metal conduit 346-7, 348-11 Liquidtight flexible nonmetallic conduit, Re-bar electrodes, 250-81(c) see Liquidtight flexible nonmetallic conduit Receptacles, 410-L Metal-trough, sound recording, 640-4 Anesthetizing locations, 517-64(f) Number of conductors, 300-17 Branch circuits, 210-7, 210-52 Pliable, 331-1 Configurations, Figs. 550-5(c), 551-46(c) Rigid metal conduit, see Rigid metal Critical branch, 517-33(a) conduit Definition, Art. 100-A Rigid nonmetallic conduit, see Rigid non- Disconnecting means, 422-22, 440-63 metallic conduit Secured, 300-11 Faceplates, 410-56(d) Service, see Service raceways Grounding type, 250-50(b) Ex., 250-74, Signaling and power circuits, power- 410-58, 517-13, 517-19(g) limited, 725-15, 725-16, 725-38(a) Hazardous (classified) locations, 501-12, Support for nonelectrical equipment, 502-13, 503-11 300-11 Health care facilities, 517-13, 517-18, Supporting conductors, vertical, 300-19 517-19 Surface metallic, see Suface metallic Insulated grounded terminals, 517-16 raceways Less than 50 volts, 720-6, 720-7 Surface nonmetallic, see Surface nonme- Marinas and boatyards, 555-3 tallic raceways Maximum cord- and plug-connected load Underfloor, see Underfloor raceways to, Table 210-21(b)(2) 70-908 NATIONAL ELECTRICAL CODE Minimum ratings, 410-56(a) Power supply, 551-46 Mobile homes, 550-8 Splices and terminals, 551-50 Nongrounding-type, replacement, 210-7 Ex. Definitions, 551-2 Outdoor, see Outdoor receptacles Distribution panelboard, 551-45 Outlet Expandable units, connection, 551-47(p) Definition, Art. 100-A Generator installations, 551-30 Outlets, where required, dwellings, Ground-fault circuit-interrupter, 551-41(c) 210-52 Grounding, 551-54, 551-55 Patient bed location, 517-18(b), 517-19(b) Grounding conductor splices, 551-50 Ratings for various size circuits, Table Identification of grounded conductor, 210-21(b)(3) 551-49 Recreational vehicles, 551-52 Lighting fixtures, 551-53 Selected, health care facilities, 517-33(a) Low voltage systems, 551-B Definition, 517-3 Multiple supply source, 551-31 Show windows, in, 210-62 Outlet boxes, 551-48 Swimming pools, 680-6 Overcurrent protection Branch circuit, 551-43 Temporary wiring, 305-4(c) and (d), 305-6 Distribution panelboard, 551-45 Low voltage wiring, 551-10(e) Terminals, identification, 200-10 Power sources, other, 551-D Theaters, 520-23, 520-45 Power supply assembly, 551-44, 551-46 Recessed lighting fixtures, 410-M Receptacles, 551-20(f), 551-41, 551-52 As raceways, 410-11, 410-31 Switches, 551-51 Clearances, installation, 410-66 System voltages, 551-E Construction, 410-N Tags, labels, and marking, 551-46(d) Temperatures, 410-65 Tests, factory, 551-F Wiring, 410-67 Wiring methods, 551-10(c), 551-47 Recording systems, Art. 640 Refrigeration compressor motors and Recreational areas, essential electrical controls, Art. 440 systems, 517-42(e) Refrigerators, grounding, 250-45 Recreational vehicle parks, 551-G Regulator bypass switch Calculated load, 551-73 Definition, 110-B Demand factors, Table 551-73 Relays Definitions, 551-2 Overload, motor overcurrent protection, Disconnecting means, 551-76(b) 430-40 Distribution system, 551-72 Reverse-current, transformers, 450-5(b) Ground-fault circuit-interrupter protec- Remote-control, signaling, and powertion, 551-71 limited circuits, 250-43(i), Art. 725 Grounding, 551-75, 551-77 Class 1 circuits, 725-B Outdoor equipment, protection of, 551-78 Circuits beyond one building, 725-19 Overcurrent protection, 551-74 Conductors, 725-16 Overhead conductors, 551-79 Different systems, 725-15 Receptacles, 551-71, 551-81 Insulation, 725-16(b) Recreational vehicle site supply equip- Number in raceways, 725-17 ment, 551-76 Overcurrent protection, 725-12 Underground wiring, 551-80 Size and use, 725-16(a) Recreational vehicle site Grounding, 725-20 Definition, 551-2 Location, 725-2, 725-13 Stand Overcurrent protection, 725-12, 725-13 Definition, 551-2 Physical protection, 725-18 Power limitations, 725-11 Recreational vehicles (camping trailers, Wiring methods, 725-14 motor homes, travel trailers, Class 2 and Class 3 circuits, 725-C truck campers), Art. 551 Applications of PLTC cables, 725-53 Appliance accessibility, 551-57 Circuits beyond one building, 725-42 Attachment plugs, 551-20(f), 551-46(c) Conductors, 725-38, 725-42 Batteries, 551-10(d) Fire resistance of cable, 725-49 Bonding, 551-56 Grounding, 725-43 Branch circuits, 551-42 Installation, 725-50, 725-52 Calculation for loads, 551-42(d) Interconnection of power supplies, Combination electrical systems, 551-C 725-32 Conductors, 551-10(b), 551-48 Location, 725-2 Connections Marking, 725-34, 725-50 Grounding, 551-54, 551-55 Overcurrent protection, 725-35, 725-36 INDEX 70-909 Power limitations, 725-31, Tables 725- Uses not permitted, 347-3 31(a) and (b) Uses permitted, 347-2 Types of cable, 725-51 Road show connection panel, 520-50 Wiring methods Load side, 725-38 Rod electrodes, 250-83(c) Supply side, 725-37 "Romex", see Nonmetallic-sheathed cable Classifications, 725-3 Room air conditioners, see Air condition- Class 1 and Class 4, 725-11 ers, room Class 2 and Class 3, 725-31 Communication cables, 725-5 Running threads, 345-9(b), 346-9(b) Motors, 430-F Safety, examination of equipment for, Safety-control equipment, 725-4 90-7 Remote-control circuit, see Circuits, Screw shells Remote-control Identification Remote-control switches, 517-160(c)(4) Polarity, 200-10(c), 410-23 Terminals, 200-10 Requirements for electrical installations, Lampholders, 410-H Art. 110 Sealable equipment Residential occupancies, see Dwellings Definition, Art. 100-A Resistance Sealing, conduit systems, 501-5, 502-5; AC resistance and reactance, cables, see also Hazardous (classified) Chap. 9 Table 9 locations Conductor properties, Chap. 9 Table 8 Intrinsically safe systems, 504-70 Insulation, 110-7 Temperature changes, 300-7(a) Welders, 630-D Underground services, 230-8. Resistance to ground, made electrodes, Secondary ties, transformers, 450-6 250-84 Separately derived systems, 250-5(d), Resistors and reactors, Art. 470 250-26 Combustible material, on, near, 470-3 Definition, Art. 100-A Conductor insulation, 470-4 Location, 470-2 Service cables, Art. 338 Over 600 volts, 470-B Buildings, 230-51 Definition, Art. 100-A Rheostats, construction specifications, Installation, Art. 338 430-82(c) Physical damage, 230-50 Rigid metal conduit, Art. 346 Service head, 230-54 Bends, 346-10, 346-11 Terminating, service equipment, 230-55 Boxes and fittings, 346-13 Underground, 230-C, 300-5 Bushings, 346-8 Service conductors, see Conductors, Cinder fill, 346-3 Service Construction specifications, 346-B Couplings and connectors, 346-9 Service drops Expansion joints, 300-7(b) Clearances, 230-24 Minimum size, 346-5 Connections, service head, 230-54 Number of conductors, 346-6, Chap. 9 Definition, Art. 100-A Table 1 Means of attachment, 230-27 Reaming ends, 346-7 Minimum size, 230-23 Splices and taps, 346-14 Number, 230-2, 230-21 Supports, 346-12 Point of attachment, 230-26; 230-28 Use, 346-1 Supports over buildings, 230-29 Wet locations, 346-4 Termination, 230-24, 230-26, 230-28 Rigid nonmetallic conduit, Art. 347 Service equipment Bends, 347-13, 347-14 Definition, Art. 100-A Boxes and fittings, 347-15, 370-13 Service lateral Bushings, 347-12 Definition, Art. 100-A Construction specifications, 347-17 Service loads, calculations, Art. 220 Description, 347-1 Expansion joints, 300-7(b), 347-9 Service raceways Joints, 347-6 Conductors, others permitted in, 230-7 Minimum size, 347-10 Drainage, raintight, 230-53, 230-202(g) Number of conductors, 347-11 Grounding and bonding, 230-63 PVC Schedule 80, 300-5(d), 551-80(b), Service head, 230-54 710-3(b)(1) Terminating at service equipment, 230-55 Splices and taps, 347-16 Underground, 230-C Supports, 347-8, Table 347-8 Service stations, gasoline, see Gasoline Trimming ends, 347-5 dispensing and service stations 70-910 NATIONAL ELECTRICAL CODE Service-entrance cable, Type SE, USE, Ground-fault protection, 230-95 Art. 338 Insulation, 230-22, 230-23 Branch circuits or feeders, 338-3 Number, 230-2 Definition, 338-1 Over 600 volts, 230-H Grounding frames of ranges and clothes Supply to one building through another, dryers, 250-60(c) 230-3 Installation methods, interior, 338-4 Two or more buildings, 250-24 Marking, 338-5 Underground, 230-C Service-entrance conductors, Art. 230-D, Setting (of circuit breaker) 338-2 Definition, Art. 100-A Underground, 338-1(b) Use, 338-1 thru 338-3 Shafts, wiring, in, 725-38(a)(4) Service-entrance conductors, 230-D, Shielded nonmetallic-sheathed cable, 338-2 Type SNM, Art. 337 Conductor sets, number of, 230-40 Bends, 337-4 Considered outside of building, 230-6 Bonding, 337-7 Definitions, Art. 100-A Construction, 337-8 Disconnecting means, 230-F Definition, 337-1 Drip loops, 230-52 Fittings, 337-6 Insulation, 230-41 Handling, 337-5 Over 600 volts, 230-H Marking, 337-9 Overcurrent protection, 230-90, 230-91, Uses permitted, 337-3 230-208 Shielding, see Guarding, guards Physical damage, 230-49, 230-50 Short-circuit withstand rating Service head, 230-54 Definition, 430-83 Size, 230-42 Splices, 230-46 Short-time duty Underground, 230-49 Definition, Art. 100-A Wiring methods, 230-43 Show cases, wall cases, 410-29 Service-entrance equipment Show windows Disconnecting means, 230-F Definition, Art. 100-A Connections, ahead of, 230-82 Flexible cords, 400-11 Connections to terminals, 230-81 Lighting fixtures, 410-7 Disconnection of grounded conductor, Branch circuits, 220-3(c) 230-75 Feeders, 220-10(a), 220-12 Electrically operated, 230-94 Ex. 6 Receptacles, 210-62, 370-17(b) Ex. Externally operable, 230-78 Signs, 600-34(e) Ground-fault, protection at, 230-95, Sidelights, borders and proscenium, 705-32 520-44 Indicating, 230-77 Location, 230-70(a) Signaling circuits, see also Fire protec- Marking, 230-66, 230-70(b) tive signaling systems; Remote- Maximum number of disconnects, six control, Signaling and powerswitch rule, 230-71 limited circuits Multiple occupancy buildings, 230-72(c) Definition, Art. 100-A Over 600 volts, 230-205, 230-206 Health care facilities, 517-F Rating, 230-79 Installation requirements, Art. 725 Simultaneous openings, 230-74 Signals for heated appliances, 422-12 Six switch rule, 230-71 Signs Suitable for use, 230-70(c) Electric, Art. 600 Transfer equipment, 230-83 Definition, Art. 100-A Grounding, bonding, guarding, 230-62, Over 1000 volts, 600-C under 1000 230-63, 230-62 volts, 600-B Overcurrent protection, 230-G Exit, health care facilities, 517-32(b), Location, 230-91, 230-92 517-42(b) Over 600 volts, 230-208 Discharge, lighting, electric, 410-P, Relative location, 230-94 410-Q Specific circuits, 230-93 Grounding, 250-43(g) Ungrounded conductors, 230-90(a) Mandated standby, 701-9 Panelboards as, 384-B Outline lighting, Art. 600 Service-point (over 600 volts), 230-200 Size of conductors, 600-21(b), 600-31(b) Definition, Art. 100-A Standby, 702-8 Services, Art. 230 Warning, see Warning signs Definition, Art. 100-A Snap switches Emergency systems, 700-12(d) Accessibility, grouping, 380-8 Farm, 220-40 Definition, Art. 100-A INDEX 70-911 Motors, 430-83, 430-109 Open wiring, 320-6 Panelboards, 384-16(b), 384-19 Space heating cables, 424-40 Ratings, 380-14 Surface raceways, 352-7 Snow melting, see Fixed outdoor electric Underfloor raceways, 354-6 deicing and snow-melting equipment Underground, 300-5(e) Wireways, 362-7 Solar cell Definition, 690-2 Spray, application, dipping, and coating processes, Art. 516 Solar photovoltaic systems, Art. 690 Classification of locations, 516-2 Circuit sizing and current, 690-8 Equipment, 516-3 thru 516-5, 516-7 Connection to other sources, 690-G Powder coating, 516-6 Definitions, Art. 100-A, 690-2 Spray washers 422-8(d)(3) Disconnecting means, 690-C Wiring, 516-3, 516-7 Grounding, 690-E Installation, 690-4 Spread of fire or products of combustion, see Fire spread Marking, 690-F Maximum voltage, 690-7 Stage equipment, theaters Overcurrent protection, 690-9 Fixed, 520-C Storage batteries, 690-H Portable, 520-E Wiring methods, 690-D Stages, motion picture and television, Solderless (pressure) connector, see 530-B Connectors, Pressure (solderless) Switchboards, 520-B, 520-D Sound recording equipment, Art. 640 Stairway chair lifts, see Elevators, dumb- Motion picture projectors, 540-50 waiters, escalators, moving walks, Theaters, 520-3 wheelchair lifts, and stairway chair lifts Space Stand-alone system Cabinets and cutout boxes, 373-7, 373-9, Definition, 690-2 373-11 Climbing, see Climbing space Standby systems, see Emergency sys- Lightning rods, conductor enclosures, tems; Legally required standby sysequipment, 250-46, 250-86 tems; Optional standby systems Outside branch circuits and feeders, Steel siding, 250-44 (FPN) 225-14 Storage batteries, Art. 480 Over 600 volts, separation, 110-33, Aircraft hangars, 513-9 230-202(d) Charging equipment, 503-14 Service conductors, 230-51(c) Definition, 480-2 Working, see Working space Emergency systems, 700-12(a) and (f) Space heating, fixed, see Fixed electric Garages, 511-8 space heating equipment Insulation, 480-5, 480-6 Locations, 480-8 Spacing between bare metal parts, Table Racks and trays, 480-7 384-26 Recreational vehicles, 551-5 Spas and hot tubs, 680-D Solar photovoltaic systems, 690-H Indoor installations, 680-41 Sound recording equipment, 640-9 Outdoor installations, 680-40 Vents, 480-9 Protection, 680-42 Submersible equipment, 680-51 Special permission, see Permission, Special Substations Splices and taps Motion picture and television studios, Antennas, 810-14 530-F Auxiliary gutters, 374-8 Over 600 volts, 710-24 Cabinets and cutout boxes, 373-8 Ex. Subsurface Cellular concrete floor raceways, 358-12 Enclosures, 110-12(b) Cellular metal floor raceways, 356-6 Supports, see articles on wiring and Concealed knob-and-tube, 324-12 equipment Conduit bodies, 370-6(c) Suppressors, radio noise, 810-4 Construction sites, 305-4(g) Surface metal raceways, 352-A Deicing and snow-melting, 426-24(b) Combination, 352-6 Electrical metallic tubing, 348-14 Conductors, 352-3, 352-4 Flat cable assemblies, 363-9, 363-10 Extension through floors and walls, 352-5 Flexible cords, 400-9 General and installed, 352-8 General provisions, 110-14 Grounding, 352-9 Messenger supported wiring, 321-8 Splices and taps, 352-7 Nonmetallic extensions, 342-5 Use, 352-1 70-912 NATIONAL ELECTRICAL CODE Surface nonmetallic raceways, 352-B Wet locations, 384-6 Combination, 352-26 Working spaces about, 110-16, 384-4 Conductors, 352-24, 352-25 Switches, Art. 380; see also Hazardous Description, 352-21 (classified) locations; specific types Extension through walls and floors, of switches 352-28 Accessibility and grouping, 380-8 General, 352-27 Splices and taps, 352-29 AC general use snap switch, 380-14(a) Use, 352-22 AC-DC general use snap switches, see AC-DC general use snap switches Surfaces, exposed conductive Air-conditioning and refrigerating equip- Definition, 517-2 ment, 440-B Surge arresters, see Lightning (surge) Appliances, 422-25 arresters Bypass isolation Surge protection, see Lightning (surge) Definition, Art. 100-A protection Circuit breakers used as, 240-83(d) Definitions, Art. 100-A Swimming pools, fountains, and similar Devices over 600 volts installations, Art. 680 Definition, 100-B Approval of equipment, 680-2 Bonding, 680-22 Disconnecting means Ceiling fans, 680-6 Appliances, 422-D Cord- and plug-connected equipment, Motors, controller, 430-H 680-7 Services, 230-F Deck area heating, 680-27 Emergency systems, 700-E Definitions, 680-4 Heat generating equipment, 665-47 Floating lake pumps, 680-H X-ray equipment, 517-72, 660-B Ground-fault circuit-interrupters, 680-5 Enclosures, installation in, 450-8(c) Fountains, 680-51 Essential electrical systems, 517-41(b) Hydromassage bathtubs, 680-70 General use, Art. 380 Junction boxes for, 680-21 Definition, Art. 100-A Receptacles, 680-6 Identification, 110-22 Spas, hot tubs, 680-40 Interrupter Storable pool wiring, required for, Definition, 100-B 680-31 Isolating Therapeutic pools, 680-62 Definition, Art. 100-A Wiring to, 680-21(b) Motors over 100 HP, 430-109 Ex. 4 Grounding, 680-24, 680-25 Services over 600 volts, 230-204 Hydromassage bathtubs, 680-G Knife, see Knife switches Junction boxes and enclosures, 680-21 Limit, cranes and hoists, 610-33 Lighting, 680-6 Manually operable, Art. 380 Overhead conductor clearances, 680-8 Mobile homes, fixtures and appliances, Permanently installed, 680-B 550-9(e) Receptacles, location and protection, Motor circuit 680-6 Definition, Art. 100-A Spas and hot tubs, 680-D Motor controllers, 430-G Storable, 680-C Panelboards, 384-16(b), 384-19 Switching devices, 680-6 Regulator bypass, see Regulator bypass Therapeutic pools and tubs, 680-F switch Transformers, 680-5, 680-20(a)(1), 680- Service, 230-F 21(b) Signs, outline lighting, 600-2, 600-35 Underwater audio equipment, 680-23 Snap, see Snap switches Underwater lighting fixtures, 680-20 Theater dressing rooms, 520-73 Switchboards, Art. 384 Transfer Clearances, 110-16, 384-7, 384-8 Definition, Art. 100-A Conductor insulation, 384-9 Unit, appliances, 422-25 Construction specifications, 384-C Definition, Art. 100-A Switchgear, metal-enclosed, 230-202(h), Easily ignitable materials, near, 384-7 230-208, 710-9, 710-24 Grounding frames, 384-11 Tables, Chap.9, App. B Grounding instruments, 384-12 AC resistance and reactance cables, Guarding live parts, 110-17 Chap. 9, Table 9 Illumination, 110-16(e) Ampacities Location, 384-3, 384-5 thru 384-7 Cable, IGS, Table 325-14 Portable, theater stages, 520-D Cable insulated, over 2000 volts Stage, 520-B Three conductor aluminum in isolated Support, busbars, conductors, 384-3 conduit in air, Table 310-76 INDEX 70-913 Three conductor aluminum in under- Wound-rotor secondaries, Table 430-23(c) ground electrical ducts, Table Bare metal parts, spacings between 310-80 switchboard and panelboard, Table Three conductor aluminum isolated in 384-26 air, Table 310-72 Branch-circuit requirements, Table Three conductor copper in under- 210-24 ground electrical ducts, Table Cable markings, Tables 725-50, 760-19, 310-79 760-50, 770-50, 800-50, 820-50 Three conductor copper isolated in Cable substitutions, Table 760-53 air, Table 310-71 Cable trays, grounding, Table 318-7(b)(2) Triplexed or three single conductor Cable fill, Tables 318-9, 318-10 aluminum in underground electrical ducts, Table 310-77 Calculation of feeder loads by occupancies, Table 220-11 Triplexed or three single conductor Conductors aluminum in isolated conduit in air, Table 310-74 Application, Tables 310-13, 310-61, 402-3 Triplexed or three single conductor copper in isolated conduit in air, Clearances, services, Table 230-51(c) Table 310-73 Deflection, minimum bending space in Conductor, single insulated, isolated in cabinets, cutout boxes, Tables air, over 2000 volts 373-6(a), 373-6(b) Dimensions Aluminum, Table 310-70 Copper, Table 310-69 Aluminum building wiring, Chap. 9 Table 5A Conductors, three single insulated in underground electrical ducts, over Asbestos-varnished-cambric, Chap. 9 Table 7 2000 volts, Table 310-78 Crane and hoist motor conductors, Lead-covered, Chap. 9 Table 6 Table 610-14(a) Rubber, thermoplastic-covered, Fixture wire, Table 402-3 Chap. 9 Table 5 Flexible cord, Table 400-4 Fire protective signaling systems, General conductors, 0 through 2000 volts Table 760-51 Aluminum, copper, or copper-clad Fixture wires, Chap. 9, Table 402-3 aluminum in raceways or cables Flexible cords and cables, types, Table types AC, NM, NMC SE, Tables 400-4 310-16, 310-18 Grounding, size Aluminum, copper, or copper-clad For AC equipment, Table 250-95 aluminum, single conductor in free For grounded systems, Table 250-94 air, Tables 310-17, 310-19 Insulations, Tables 310-13, 310-61 thru Bare or covered conductors, Table 310-63 B-310-4 Maximum number, Chap. 9, Tables 3A Multiconductor cables, types TC, thru 3F MC, MI, and SNM in free air, Number in metal boxes, Table 370-6(a) Table B-310-3 Over 600 to 35,000 volts Three conductor cable in raceway in Ampacities, Tables 310-81 thru free air, Table B-310-1 310-84 Three insulated conductors in cable Shielding, solid dielectric-insulated in underground electrical ducts, conductors, Table 310-64 Table B-310-6 Varnished cambric, multiple- Three single insulated conductors conductor cables, Table 310-66 directly buried in earth, types UF, Varnished cambric, single- USE, Table B-310-10 conductors, Table 310-65 Three single insulated conductors in Support, vertical raceways, 300-19(a) nonmagnetic underground electrical Volume required per conductor, ducts, Table B-310-5 Table 370-6(b) Three single insulated conductors in Conduit or tubing underground electrical ducts, Table Combination of conductors, percent B-310-7 area fill, Chap. 9 Table 1 Three triplexed single insulated con- Dimensions, Table 325-22, Chap. 9 ductors directly buried in earth (UF Table 4 and USE cables), Table B-310-9 Expansion characteristics, Chap. 9, Two or three insulated conductors Tables 10 and 11 cabled within an overall covering Flexible metal (g in.), Table 350-3 directly buried in earth, Table Number of conductors in, Chap. 9 B-310-8 Tables 1, 2, 3A, 3B, 3C Two or three single insulated Con- Radius of bends, rigid metal conduit, ductors supported on a messenger, Table 346-10 Table B-310-2 Supports, Tables 346-12, 347-8 70-914 NATIONAL ELECTRICAL CODE Cooking appliances, demand factors and Transformers, medium and high voltage, loads, Tables 220-19, 220-20 Tables 450-3(a)(1), 450-3(a)(2)(b) Farm load, method for computing, Tamperability Tables 220-40, 220-41 Circuit breakers, 240-82 General lighting unit loads by occupan- Type S fuses, 240-54(d), 550-6 cies, Table 220-3(b) Household clothes dryers, demand loads, Tamperproof receptacles, see Recepta- Table 220-18 cles, Tamperproof Household ranges and similar cooking Taps, see also Splices and taps appliances, demand loads, Table Branch circuit, 210-19 220-19 Busways, 364-12 Ex. 1 Integrated gas spacer cable Feeders, see Feeders, Taps Ampacity, Table 325-14 Overcurrent protection, 240-21 Conduit dimensions, Table 325-22 Service-entrance conductors, 230-46 Minimum radius of bends, Table 325-11 Task illumination, 517-33(a) Paper spacer thickness, Table 325-22 Definition, 517-3 Live parts, separation Over 600 volts Telegraph systems, see Communication circuits Air separation, indoors, Table 710-33 Elevation, Table 110-34(e) Telephone equipment, 800-51(i); see also Working space, Table 110-34(a) Communication circuits Working clearances, Table 110-16(a) Telephone exchanges, circuit load, Minimum radius of bend, IGS cable, 220-3(c) Ex. 4 Table 325-11 Minimum size of conductors, Table 310-5 Telephone systems, see Communication Minimum wire bending space, Tables circuits 373-6(a) and (b) Television and radio distribution sys- Mobile home park demand factors, Table tems, see Community antenna tele- 550-22 vision and radio distribution Motors systems Controller enclosure selection, Table Television equipment, see Radio and tele- 430-91 vision equipment Full-load currents, Tables 430-147 thru 430-150 Television studios, Art. 520, Art. 530 Locked-rotor, code letters, Table Temperature limitations 430-7(b) Conductors, 310-10 Locked-rotor current conversion, In outlet boxes for fixtures, 410-11 Table 430-151 Nonmetallic raceways and tubing, see Marking on motors, 430-7(a) and (b) Raceway of tubing type Maximum rating or setting, branch Service-entrance cable, 338-3(c) circuit protective devices, Table 430-152 Temporary wiring, Art. 305 Number and location, overload units, Branch circuits, 305-4(c) Table 430-37 Disconnecting means, 305-4(e) Terminal, spacing and housing, Tables Feeders, 305-4(b) 430-12(b) and (c) Grounding, 305-5 Multifamily dwellings, optional calcula- Guarding over 600 volts, 305-7 tion demand factors, Table 220-32 Lamp protection, 305-4(f) Optional load calculations, one family Receptacles, 305-4(d), 305-6 residences, Tables 220-30, 220-31 Services, 305-4(a) Time constraints, 305-3 Overcurrent protective device, maximum rating, Table 430-72(b) Terminal housing, grounding through Paper spacer thickness, IGS cable, Table motor, 430-145(a) 325-21 Terminals Radio and TV equipment, antenna sizes Connections to, 110-14, 250-112, 250-113 Amateur stations, Table 810-52 Electric discharge tubing, signs, etc., Receiving stations, Table 810-16(a) 600-34 Rating factors for power resistors, Table Flat conductor cable, 363-20 430-29 Identification Receptacle loads, nondwelling units, Fire protective signaling system, 760-4 Table 220-13 Motors, controllers, 430-9 Recreational vehicle park demand fac- Polarity, 200-9 thru 200-11 tors, Table 551-73 Wiring device, 250-119 Restaurants, optional method load calculation, Table 220-36 Tests Schools, optional method load calcula- Emergency systems, 700-4 tion, Table 220-34 Ground-fault protection, 230-95(c) INDEX 70-915 Insulation resistance, space heating 1000 volts or less, 410-P cables, 424-45 More than 1000 volts, 410-Q Legally required standby systems, 701-5 Instrument, grounding, 250-L Lighting fixtures, 410-45 Connections at services, 230-82 Ex. 4 Mobile homes, 550-12 Isolation Recreational vehicles, 551-60 Anesthetizing locations and patient care Theaters, Art. 520 areas, 517-19(f), 517-20, 517-63(a) Arc lamps, 410-55 Definition, 517-3 Dressing room, 520-F Less-flammable liquid-insulated, 450-23 Emergency lighting systems, Art. 700 Location, 450-13 Grounding, 520-G Modification of, 450-28 Fixed electric equipment, 250-43(f) Motor control circuit, 430-72(c) Overcurrent protection, 450-3 Stage equipment Power-limited and signaling circuits, Fixed, 520-C remote control, 725-11(a)(1), 725-31 Portable, 520-E Switchboard Remote control circuits for, 430-74(b), 725-11, 725-31 Fixed, 520-B Research and development, 450-1 Ex. 8 Portable, 520-D Signs and outline lighting, 600-32 Therapeutic equipment, 517-73(b) Special provisions, 450-B Therapeutic high-frequency diathermy Two-winding, underwater lighting, equipment 680-5(a) Vaults, 450-C Definition, 517-3 X-ray equipment, 517-76, 660-C Therapeutic pools and tubs, 517-90(c), Transmitting stations, radio and televi- 680-4, 680-F sion, 810-C Thermal cutouts Travel trailer Definition, Art. 100-A Definition, 551-2 Disconnecting means, 240-40 Trays, storage batteries, 480-7(b) Thermal devices Trees, lighting fixtures supported by, Overcurrent protection, 240-9 410-16(h) Thermal protector Truck camper Definition, Art. 100-A Definition, 551-2 Thermal resistivity, B-310-15(b)(2) Tubing, see also Conduit Electric discharge, signs, etc., 600-33, Thermally protected (thermal protection) 600-34 Definition, Art. 100-A Electrical metallic, see Electrical metallic Fixtures, recessed, 410-65(c) tubing Fluorescent lamp ballasts in fixtures, Electrical nonmetallic, see Electrical 410-73(e) nonmetallic tubing Three overload units, motors, Table Flexible metallic, see Flexible metallic 430-37 tubing TV, see Television Tools Double insulated, 250-45(b) Ex. 3 Underfloor raceways, Art. 354 Metal working machine, see Industrial Conductors, 354-4, 354-5 machinery Connections to cabinets, wall outlets, 354-15 Motor-operated, hand-held, grounding, 250-45(c) Covering, 354-3 Dead ends, 354-10 Trailers, types of Discontinued outlets, 354-7 Definition, 551-2 Inserts, 354-14 Transfer switch Junction boxes, 354-13 Definition, Art. 100-A Laid in straight lines, 354-8 Markers, where required, 354-9 Transformer vaults, 450-C Splices and taps, junction boxes, 354-6 Transformers, Art. 450; see also Hazard- Use, 354-2 ous (classified) locations Underground circuits, communication, Arc welders, 630-B 800-11 Autotransformers, 450-4, 450-5 Underground enclosures, 110-12(b) Capacitors, 460-2 Underground feeder and branch circuit Installation, Art. 450 cable, Type UF, Art. 339 X-ray equipment, 517-148, 660-C Ampacity, 339-5 Definitions, 450-2 Description and marking, 339-1 Dry-type, 450-21, 450-22 Overcurrent protection, 339-4 Electric discharge lighting systems Use, 339-3 70-916 NATIONAL ELECTRICAL CODE Underground wiring, see also Hazardous Drop (classified) locations Branch circuits, 210-19(a)(FPN) Buried conductors, Types USE, UF, Conductors sized to prevent, 310- 338-1(b), 339-3 15(b)(FPN) Conductor types in raceways, 310-8 Feeders, 215-2(FPN) Intermediate metal conduit, 345-3 Electric discharge lighting, 410-P, 410-Q Liquidtight flexible metal conduit, 351-4 General provisions, 110-4 Minimum cover requirements, 300-5(a) Ground to Over 600 volts, 710-3(b) Definition, Art. 100-A Rigid metal conduit, 346-1 High Rigid nonmetallic conduit, 347-2 Definition, 710-2 Services, 230-30, 230-41 Less than 50, Art. 720 Splices and taps, 300-5(e) Limitations, elevators, dumbwaiters, Swimming pools, 680-10 escalators, moving walks, 620-2 Wet locations, 310-8 Marking, 240-83(e) Nominal Uninterruptible power supplies (UPS), 645-11 Definition, Art. 100-A Nominal battery Unit equipment, emergency and standby Definition, 480-2 systems, 700-12(f), 701-11(f) Over 600 volts, Art. 710 Unused openings Swimming pool underwater lighting fixtures, 680-20 Boxes and fittings, 110-12, 370-18 Cabinets and cutout boxes, 373-4 Wiring methods, 300-2 Utilization equipment Wading pools Definition, 680-4 Definition, Art. 100-A Wall or show cases, see Show cases, wall Vapors, flammable, see Hazardous (clascases sified) locations Wall-mounted ovens, see Ovens, Wall- Varying duty mounted Definition, Art. 100-A Warning signs (labels), at equipment Vaults Aircraft hangars, 513-6 thru 513-11 Capacitors, 460-2 Electroplating, 669-7 Film storage, 530-E Electrostatic hand spraying, 516-5(c) Service over 600 volts, 230-208, 110-31, Guarding live parts 600 volts or less, 710-31 110-17(c)(FPN) Service 600 volts or less, 230-6 Induction and dielectric heating, 665-23 Transformers, 450-C Locked room or enclosure with live parts over 600 volts, 110-34(c), 710- Vehicles Electric, charging, 511-8 21(c)(2), 710-24(o)(2), 710-43, 710-45 Services over 600 volts, 230-203 Recreation Definition, 551-2 Transformers, 450-8(d) Water heaters, 422-14 Ventilated Nameplate load, 220-32(c)(3) Definition, Art. 100-A Protection, 422-14 Ventilating ducts, wiring, 300-21, 300-22 Water pipe Ventilating piping for motors, etc., 502-9, As grounding electrode, 250-81(a) 503-7 Bonding (metal), 250-80(a) Ventilation Connections, 250-112, 250-113 Aircraft hangars, 513-2(d) Water pumps, 547-8(d) Battery locations, 480-8 Watertight Equipment, general, 110-13(b) Definition, Art. 100-A Motors, 430-14(a), 430-16 Positive-pressure, 500-2 Ex., (FPN No. 2) Weatherproof Transformers, 450-9, 450-45 Definition, Art. 100-A Vessel, fixed electric heating equipment for Welders, electric, Art. 630 Definition, 427-2 Definition, Art. 100-A Motor-generator arc, 630-C Viewing tables, motion picture, 530-D Resistance, 630-D Volatile flammable liquid Transformer and rectifier arc, 630-B Definition, Art. 100-A Welding cable, 630-E Voltage and volts Well casings, metal, 547-8(d) Branch circuits, limits, 210-6 Wet locations, see also Damp or wet Circuit locations Definition, Art. 100-A Conductors, types, 310-8, Table 310-13 INDEX 70-917 Definition, Art. 100-A Extensions through walls, 362-24 Electrical metallic tubing, 348-4 Marking, 362-27 Enameled equipment, 300-6(a) Splices and taps, 362-21 Fixtures in, 410-4 Supports, 362-22 Health care facilities, 517-20 Uses, 362-15, 362-16 Intermediate metal conduit, 345-5 Mounting of equipment, 300-6(c) Wiring methods; Art. 300; see also Haz- Rigid metal conduit, 346-4 ardous (classified) locations Rigid nonmetallic conduit, 347-2(d) Ducts, 300-21, 300-22 Switchboards, 384-5 General requirements for, see General Switches, 380-4 requirements for wiring methods Wheelchair lifts, see Elevators, dumbwait- Health care facilities, 517-B ers, escalators, moving walks, Intrinsically safe systems, 504-20 wheelchair lifts, and stairway chair Mobile homes, 550-10 lifts Planning, 90-8 Windows, show, see Show windows Recreational vehicles, 551-10(c), 551-47 Temporary, see Temporary wiring Wire in concrete footings, electrodes, Theaters, 520-4 250-81(c) Types and materials, Chap. 3 Wired fixture sections, 410-77(c) Within sight from, see In sight from Wires, see Conductors; Cords; Fixture wire Working space About electrical equipment, 110-16, Wireways, metal, 362-A 110-32 thru 110-34 Conductors, 362-4, 362-5 Adjacent to live parts (circuits over 600 Dead ends, 362-10 volts), 110-33, 110-34 Definition, 362-1 Motion picture projectors, 540-12 Deflected insulated, 362-6 Service equipment, 230-64 Extensions, 362-11 Switchboards, 384-4, 384-8 Extensions through walls, 362-9 Grounding, 362-13 Workmanlike installation, 110-12 Marking, 362-12 X-ray equipment, 517-E, Art. 660 Splices and taps, 362-7 Control, 517-74, 660-B Supports, 362-8 Fixed and stationary Use, 362-2 Definition, 660-2 Wireways, nonmetallic, 362-B Guarding and grounding, 517-77, 660-D Conductors, 362-18 thru 362-20 Installation, 517-E Dead ends, 362-25 Definition, 517-3 Definition, 362-14 Transformers and capacitors, 517-76, Expansion joints, 362-23 660-C Extensions, 362-26 Types of, 600-4(b) 2. 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