The required ampacity and motor ratings shall be

determined as specified in (a), (b), and (c) below. (a) General Motor Applications. Other than as specified for torque motors in (b) below and for ac adjustable voltage motors in (c) below, where the current rating of a motor is used to determine the ampacity of conductors or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, etc., the values given in Tables 430-147, 430-148, 430-149, and 430-150, including notes, shall be used instead of the actual current rating marked on the motor nameplate. Separate motor overload protection shall be based on the motor nameplate current rating. Where a motor is marked in amperes, but not horsepower, the horsepower rating shall be assumed to be that corresponding to the value given in Tables 430- 147, 430-148, 430-149, and 430-150, interpolated if necessary. Exception No. 1: Multispeed motors shall be in accordance with Sections 430-22(a) and 430-52. Exception No. 2: For equipment employing a shaded-pole or permanent-split-capacitor-type fan or blower motor that is marked with the motor type, the full-load current for such motor marked on the nameplate of the equipment in which the fan or blower motor is employed shall be used instead of the horsepower rating to determine the ampacity or rating of the disconnecting means, the branch-circuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and the separate overload protection. This marking on the equipment nameplate shall not be less than the current marked on the fan or blower motor nameplate. (b) Torque Motors. For torque motors, the rated current shall be locked-rotor current, and this nameplate current shall be used to determine the ampacity of the branch-circuit conductors covered in Sections 430-22 and 430-24, the ampere rating of the motor overload protection, and the ampere rating of motor branch-circuit and ground-fault protection in accordance with Section 430-52(b). (FPN): For motor controllers and disconnecting means, see Section 430-83, Exception No. 3 and Section 430-110. (c) AC Adjustable Voltage Motors. For motors used in alternatingcurrent, adjustable voltage, variable torque drive systems, the ampacity of conductors, or ampere ratings of switches, branch-circuit short-circuit and ground-fault protection, etc., shall be based on the maximum operating current marked on the motor or control nameplate, or both. If the maxi- I mum operating current does not appear on the nameplate, the ampacity determination shall be based on 150 percent of the values given in Tables 430-149 and 430-150. 430-7. Marking on Motors and Multimotor Equipment. (a) Usual Motor Applications. A motor shall be marked with the following information: (1) Maker's name. (2) Rated volts and full-load amperes. For a multispeed motor, fullload amperes for each speed, except shaded-pole and permanent-split capacitor motors where amperes are required only for maximum speed. 70-390 NATIONAL ELECTRICAL CODE (3) Rated frequency and number of phases, if an alternating-current motor. (4) Rated full-load speed. (5) Rated temperature rise or the insulation system class and rated ambient temperature. (6) Time rating. The time rating shall be 5, 15, 30, or 60 minutes, or continuous. (7) Rated horsepower if 1/8 horsepower or more. For a multispeed motor 1/8 horsepower or more, rated horsepower for each speed, except shaded-pole and permanent-split capacitor motors 1/8 horsepower or more where rated horsepower is required only for maximum speed. Motors of arc welders are not required to be marked with the horsepower rating. (8) Code letter if an alternating-current motor rated ½ horsepower or more. On polyphase wound-rotor motors the code letter shall be omitted. (FPN): See (b) below. (9) Secondary volts and full-load amperes if a wound-rotor induction motor. (10) Field current and voltage for direct-current excited synchronous motors. (11) Winding: straight shunt, stabilized shunt, compound, or series, if a direct-current motor. Fractional horsepower dc motors 7 inches (178 mm) or less in diameter shall not be required to be marked. (12) A motor provided with a thermal protector complying with Sections 430-32(a) (2) or (c) (2) shall be marked "Thermally Protected. Thermally protected motors rated 100 watts or less and complying with Section 430-32(c) (2) shall be permitted to use the abbreviated marking "T.P." (13) A motor complying with Section 430-32(c) (4) shall be marked "Impedance Protected.' Impedance protected motors rated 100 watts or less and complying with Section 430-32(c) (4) shall be permitted to use the abbreviated marking "Z.P." (b) Locked-Rotor Indicating Code Letters. Code letters marked on motor nameplates to show motor input with locked rotor shall be in accordance with Table 430-7(b). The code letter indicating motor input with locked rotor shall be in an individual block on the nameplate, properly designated. This code letter shall be used for determining branch-circuit short-circuit and ground-fault protection by reference to Table 430-152, as provided in Section 430-52. (1) Multispeed motors shall be marked with the code letter designating the locked-rotor kVA per horsepower for the highest speed at which the motor can be started. Exception: Constant-horsepower multispeed motors shall be marked with the code letter giving the highest locked-rotor kVA per horsepower. (2) Single-speed motors starting on Y connection and running on delta connections shall be marked with a code letter corresponding to the locked-rotor kVA per horsepower for the Y connection. (3) Dual-voltage motors that have a different locked-rotor kVA per horsepower on the two voltages shall be marked with the code letter for the voltage giving the highest locked-rotor kVA per horsepower. ARTICLE 430 - MOTOR CIRCUITS, CONTROLLERS 70-391 (4) Motors with 60- and 50-hertz ratings shall be marked with a code letter designating the locked-rotor kVA per horsepower on 60 hertz. (5) Part-winding-start motors shall be marked with a code letter designating the locked-rotor kVA per horsepower that is based upon the lockedrotor current for the full winding of the motor. Table 430-7(b). Locked-Rotor Indicating Code Letters Kilovolt-Amperes Code per Horsepower Letter with Locked Rotor A 0 - 3.14 B 3.15 - 3.54 C 3.55 - 3.99 D 4.0 - 4.49 E 4.5 - 4.99 F 5.0 - 5.59 G 5.6 - 6.29 H 6.3 - 7.09 J 7.1 - 7.99 K 8.0 - 8.99 L 9.0 - 9.99 M 10.0 - 11.19 N 11.2 - 12.49 P 12.5 - 13.99 R 14.0 - 15.99 S 16.0 - 17.99 T 18.0 - 19.99 U 20.0 - 22.39 V 22.4 - and up (c) Torque Motors. Torque motors are rated for operation at standstill and shall be marked in accordance with (a) above. Exception: Locked-rotor torque shall replace horsepower. (d) Multimotor and Combination-Load Equipment. (1) Multimotor and combination-load equipment shall be provided I with a visible nameplate marked with the maker's name, the rating in volts, frequency, number of phases, minimum supply circuit conductor ampacity, and the maximum ampere rating of the circuit short-circuit and groundfault protective device. The conductor ampacity shall be computed in accordance with Section 430-24 and counting all of the motors and other I loads that will be operated at the same time. The short-circuit and groundfault protective device rating shall not exceed the value computed in accordance with Section 430-53. Multimotor equipment for use on two or more circuits shall be marked with the above information for each circuit. (2) Where the equipment is not factory-wired and the individual name- I plates of motors and other loads are visible after assembly of the equipment, the individual nameplates shall be permitted to serve as the required marking. 70-392 NATIONAL ELECTRICAL CODE 430-8. Marking on Controllers. A controller shall be marked with the maker's name or identification, the voltage, the current or horsepower rating, and such other necessary data to properly indicate the motors for which it is suitable. A controller that includes motor overload protection suitable for group motor application shall be marked with the motor overload protection and the maximum branch-circuit short-circuit and groundfault protection for such applications. Combination controllers employing adjustable instantaneous trip circuit breakers shall be clearly marked to indicate the ampere settings of the adjustable trip element. Where a controller is built-in as an integral part of a motor or of a motor-generator set, individual marking of the controller shall not be required if the necessary data are on the nameplate. For controllers that are an integral part of equipment approved as a unit, the above marking shall be permitted on the equipment nameplate. 430-9. Terminals. (a) Markings. Terminals of motors and controllers shall be suitably marked or colored where necessary to indicate the proper connections. (b) Conductors. Motor controllers and terminals of control circuit devices shall be connected with copper conductors unless identified for use with a different conductor. (c) Torque Requirements. Control circuit devices with screw-type pressure terminals used with No. 14 or smaller copper conductors shall be torqued to a minimum of 7 pound-inches (0.79 N-m) unless identified for a different torque value. 430-10. Wiring Space in Enclosures. (a) General. Enclosures for motor controllers and disconnecting means shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to the other apparatus unless designs are employed that provide adequate space for this purpose. (FPN): See Section 373-8 for switch and overcurrent-device enclosures. (b) Wire Bending Space in Enclosures. Minimum wire bending space within the enclosures for motor controllers shall be in accordance with Table 430-10(b) where measured in a straight line from the end of the lug or wire connector (in the direction the wire leaves the terminal) to the wall or barrier. Where alternate wire termination means is substituted for that supplied by the manufacturer of the controller, it shall be of a type identified by the manufacturer for use with the controller and shall not reduce the minimum wire bending space. 430-11. Protection Against Liquids. Suitable guards or enclosures shall be provided to protect exposed current-carrying parts of motors and the insulation of motor leads where installed directly under equipment, or in other locations where dripping or spraying oil, water, or other injurious liquid may occur, unless the motor is designed for the existing conditions. ARTICLE 430 - MOTOR CIRCUITS, CONTROLLERS 70-393 Table 430-10(b). Minimum Wire Bending Space at the Terminals of Enclosed Motor Controllers (in inches) Size of Wire Wires per Terminal* AWG or kcmil 1 2 14-10 Not specified - 8-6 1½ - - 4-3 2 - 2 2½ 1 3 - 1/0 5 5 2/0 6 6 3/0-4/0 7 7 250 8 8 300 10 10 350-500 12 12 600-700 14 16 750-900 18 19 *Where provision for 3 or more wires per terminal exists, the minimum wire bending space shall be in accordance with the requirements of Article 373. 430-12. Motor Terminal Housings. I (a) Material. Where motors are provided with terminal housings, the housings shall be of metal and of substantial construction. Exception: In other than hazardous (classified) locations, substantial, nonmetallic, nonburning housings shall be permitted provided an internal grounding means between the motor frame and the equipment grounding connection is incorporated within the housing. (b) Dimensions and Space - Wire-to-Wire Connections. Where these terminal housings enclose wire-to-wire connections, they shall have minimum dimensions and usable volumes in accordance with Table 430-12(b). (c) Dimensions and Space - Fixed Terminal Connections. Where these terminal housings enclose rigidly mounted motor terminals, the terminal housing shall be of sufficient size to provide minimum terminal spacings and usable volumes in accordance with Table 430-12(c)(1) and Table 430-12(c)(2). (d) Large Wire or Factory Connections. For motors with larger ratings, greater number of leads, or larger wire sizes, or where motors are installed as a part of factory-wired equipment, without additional connection being required at the motor terminal housing during equipment installation, the terminal housing shall be of ample size to make connections, but the foregoing provisions for the volumes of terminal housings shall not be considered applicable. (e) Equipment Grounding Connections. A means for attachment of an equipment grounding conductor termination in accordance with Section 70-394 NATIONAL ELECTRICAL CODE Table 430-12(b). Terminal Housings - Wire-to-Wire Connections Motors 11 inches in Diameter or Less Cover Opening, Usable Volume, Minimum Dimension, Minimum, HP Inches Cubic Inches 1 and smaller* 15/8 7½ 1½, 2, and 3+ 13/4 12 5 and 7½ 2 16 10 and 15 2½ 26 For SI units: one inch = 25.4 millimeters. *For motors rated 1 horsepower and smaller and with the terminal housing partially or wholly integral with the frame or end shield, the volume of the terminal housing shall be not less than 0.8 cubic inch per wire-to-wire connection. The minimum cover opening dimension is not specified. For motors rated 1½, 2, and 3 horsepower and with the terminal housing partially or wholly integral with the frame or end shield, the volume of the terminal housing shall not be less than 1.0 cubic inch per wire-to-wire connection. The minimum cover opening dimension is not specified. Motors Over 11 inches in Diameter Alternating-Current Motors Max. Full-load Current for Three- Terminal Typical phase Motors with Box Usable Maximum Max. of Twelve Minimum Volume Horsepower Leads Dimension Minimum Three Phase Amperes Inches Cubic Inches 230 Volt 460 Volt 45 2.5 26 15 30 70 3.3 55 25 50 110 4.0 100 40 75 160 5.0 180 60 125 250 6.0 330 100 200 400 7.0 600 150 300 600 8.0 1100 250 500 For SI units: one inch = 25.4 millimeters. 250-113 shall be provided at motor terminal housings for wire-to-wire connections or fixed terminal connections. The means for such connections shall be permitted to be located either inside or outside the motor terminal housing. Exception: Where a motor is installed as a part of factory-wired equipment that is required to be grounded and without additional connection being required at the motor terminal housing during equipment installation, a separate means for motor grounding at the motor terminal housing shall not be required. 430-13. Bushing. Where wires pass through an opening in an enclosure, conduit box, or barrier, a bushing shall be used to protect the conductors from the edges of openings having sharp edges. The bushing shall have ARTICLE 430 - MOTOR CIRCUITS, CONTROLLERS 70-395 Direct-Current Motors Maximum Full-Load Current for Terminal Box Usable Motors with Minimum Volume, Maximum of Six Leads Dimensions Minimum Amperes Inches Cubic Inches 68 2.5 26 105 3.3 55 165 4.0 100 240 5.0 180 375 6.0 330 600 7.0 600 900 8.0 1100 For SI units: one inch = 25.4 millimeters. Auxiliary leads for such items as brakes, thermostats, space heaters, exciting fields, etc., shall be permitted to be neglected if their current-carrying area does not exceed 25 percent of the current-carrying area of the machine power leads. Table 430-12(c)(1). Terminal Spacings - Fixed Terminals Minimum Spacing, Inches Between Line Between Terminals and Other Line Uninsulated Metal Nominal Volts Terminals Parts 240 or less 1/4 ¹/₄ Over 250 through 600 3/8 3/₈ For SI units: one inch = 25.4 millimeters. Table 430-12(c)(2). Usable Volumes - Fixed Terminals Power-Supply Minimum Usable Volume per Conductor Power-Supply Conductor, Size, AWG Cubic Inches 14 1.0 12 and 10 1½ 8 and 6 2½ For SI units: one inch = 25.4 millimeters. smooth, well-rounded surfaces where it may be in contact with the conductors. If used where oils, greases, or other contaminants may be present, the bushing shall be made of material not deleteriously affected. (FPN): For conductors exposed to deteriorating agents, see Section 310-9. 430-14. Location of Motors. (a) Ventilation and Maintenance. Motors shall be located so that adequate ventilation is provided and so that maintenance, such as lubrication of bearings and replacing of brushes, can be readily accomplished. 70-396 NATIONAL ELECTRICAL CODE (b) Open Motors. Open motors having commutators or collector rings shall be located or protected so that sparks cannot reach adjacent combustible material, but this shall not prohibit the installation of these motors on wooden floors or supports. 430-16. Exposure to Dust Accumulations. In locations where dust or flying material will collect on or in motors in such quantities as to seriously interfere with the ventilation or cooling of motors and thereby cause dangerous temperatures, suitable types of enclosed motors that will not overheat under the prevailing conditions shall be used. (FPN): Especially severe conditions may require the use of enclosed pipeventilated motors, or enclosure in separate dusttight rooms, properly ventilated from a source of clean air. 430-17. Highest Rated or Smallest Rated Motor. In determining compliance with Sections 430-24, 430-53(b), and 430-53(c), the highest rated or smallest rated motor shall be based on the rated full-load current as selected from Tables 430-147, 430-148, 430-149, and 430-150. 430-18. Nominal Voltage of Rectifier Systems. The nominal value of the ac voltage being rectified shall be used to determine the voltage of a rectifier derived system. Exception: The nominal dc voltage of the rectifier shall be used if it exceeds the peak value of the ac voltage being rectified. B. Motor Circuit Conductors 430-21. General. Part B specifies sizes of conductors capable of carrying the motor current without overheating under the conditions specified. Exception: The provisions of Section 430-124 shall apply over 600 volts, nominal. The provisions of Articles 250, 300, and 310 shall not apply to conductors that form an integral part of approved equipment, or to integral conductors of motors, motor controllers, and the like. (FPN No. 1): See Sections 300-1(b) and 310-1 for similar requirements. (FPN No. 2): See Section 430-9(b) for equipment device terminal requirements. 430-22. Single Motor. (a) General. Branch-circuit conductors supplying a single motor shall have an ampacity not less than 125 percent of the motor full-load current rating. For a multispeed motor, the selection of branch-circuit conductors on the line side of the controller shall be based on the highest of the full-load current ratings shown on the motor nameplate; the selection of branchcircuit conductors between the controller and the motor shall be based on the current rating of the winding(s) that the conductors energize. (FPN): See Chapter 9, Example No. 8 and Diagram 430-1. Exception No. 1: Conductors for a motor used for short-time, intermittent, periodic, or varying duty shall have an ampacity not less than the percentage of the motor nameplate current rating shown in Table 430- 22(a), Exception unless the authority having jurisdiction grants special permission for conductors of smaller size. ARTICLE 430 - MOTOR CIRCUITS, CONTROLLERS 70-397 Exception No. 2: For direct-current motors operating from a rectified single-phase power supply, the conductors between the controller and the motor shall have an ampacity of not less than the following percent of the motor full-load current rating: a. Where a rectifier bridge of the single-phase half-wave type is used, 190 percent. b. Where a rectifier bridge of the single-phase full-wave type is used, 150 percent. Table 430-22(a), Exception. Duty-Cycle Service Percentages of Nameplate Current Rating 5- 15- 30 & 60 Con- Minute Minute Minute tinuous Rated Rated Rated Rated Classification of Service Motor Motor Motor Motor Short-Time Duty Operating valves, raising or lowering rolls, etc. 110 120 150 Intermittent Duty Freight and passenger elevators, tool heads, pumps, drawbridges, turntables, etc. For arc welders, see