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

F. Wiring of Fixtures 410-22. Fixture Wiring - General. Wiring on or within fixtures shall be neatly arranged and shall not be exposed to physical damage. Excess wiring shall be avoided. Conductors shall be so arranged that they shall not be subjected to temperatures above those for which they are rated. 410-23. Polarization of Fixtures. Fixtures shall be so wired that the screw shells of lampholders will be connected to the same fixture or circuit conductor or terminal. The grounded conductor, where connected to a screwshell lampholder, shall be connected to the screw shell. 410-24. Conductors. (a) Insulation. Fixtures shall be wired with conductors having insulation suitable for the environmental conditions, current, voltage, and temperature to which the conductors will be subjected. (b) Conductor Size. Fixture conductors shall not be smaller than No. 18. (FPN No. 1): For ampacity of fixture wire, see Section 402-5. (FPN No. 2): For maximum operating temperature and voltage limitation of fixture wires, see Section 402-3. 410-25. Conductors for Certain Conditions. (a) Mogul-Base Lampholders. Fixtures provided with mogul-base, screw-shell lampholders and operating at not over 300 volts between conductors shall be wired with Type AF, SF-1, SF-2, SFF-1, SFF-2, PF, PGF, PFF, PGFF, PTF, PTFF, PAF, PAFF, XF, XFF, ZF, or ZFF fixture wire. (b) Other than Mogul-Base, Screw-Shell Lampholders. Fixtures provided with other than mogul-base, screw-shell lampholders and operating at not over 300 volts between conductors shall be wired with Type AF, SF-1, SF-2, PF, PGF, PFF, PGFF, PTF, PTFF, PAF, PAFF, XF, XFF, ZF, or ZFF fixture wire or Type AFC or AFPD flexible cord. Exception No. 1: Where temperatures do not exceed 90°C (194°F), Types TFN and TFFN fixture wire shall be permitted. Exception No. 2: Where temperatures exceed 60°C (140°F) but are not higher than 75°C (167°F), Types RH and RHW rubber-covered wire and Types RFH-1, RFH-2, and FFH-2 fixture wire shall be permitted. Exception No. 3: Where temperatures do not exceed 60°C (140°F), Type TW thermoplastic wire, Types TF and TFF fixture wire shall be permitted, 70-338 NATIONAL ELECTRICAL CODE including fixtures of decorative types on which lamps of not over 60-watt rating are used in connection with imitation candles. (FPN): See Table 402-3 and Section 402-3 for fixture wires and conductors; and Table 400-5(A) for flexible cords. 410-27. Pendant Conductors for Incandescent Filament Lamps. (a) Support. Pendant lampholders with permanently attached leads, where used for other than festoon wiring, shall be hung from separate stranded rubber-covered conductors that are soldered directly to the circuit conductors but supported independently thereof. (b) Size. Such pendant conductors shall not be smaller than No. 14 for mogul-base or medium-base screw-shell lampholders, nor smaller than No. 18 for intermediate or candelabra-base lampholders. Exception: Listed Christmas tree and decorative lighting outfits shall be permitted to be smaller than No. 18. (c) Twisted or Cabled. Pendant conductors longer than 3 feet (914 mm) shall be twisted together where not cabled in a listed assembly. 410-28. Protection of Conductors and Insulation. (a) Properly Secured. Conductors shall be secured in a manner that will not tend to cut or abrade the insulation. (b) Protection Through Metal. Conductor insulation shall be protected from abrasion where it passes through metal. (c) Fixture Stems. Splices and taps shall not be located within fixture arms or stems. (d) Splices and Taps. No unnecessary splices or taps shall be made within or on a fixture. (FPN): For approved means of making connections, see Section 110-14. (e) Stranding. Stranded conductors shall be used for wiring on fixture chains and on other movable or flexible parts. (f) Tension. Conductors shall be so arranged that the weight of the fixture or movable parts will not put a tension on the conductors. 410-29. Cord-Connected Showcases. Individual showcases, other than fixed, shall be permitted to be connected by flexible cord to permanently installed receptacles, and groups of not more than six such showcases shall be permitted to be coupled together by flexible cord and separable lockingtype connectors with one of the group connected by flexible cord to a permanently installed receptacle. The installation shall comply with (a) through (e) of this section. (a) Cord Requirements. Flexible cord shall be hard-service type, having conductors not smaller than the branch-circuit conductors, having ampacity at least equal to the branch-circuit overcurrent device, and having an equipment grounding conductor. (FPN): See Table 250-95 for size of equipment grounding conductor. ARTICLE 410 - LIGHTING FIXTURES, ETC. 70-339 (b) Receptacles, Connectors, and Attachment Plugs. Receptacles, connectors, and attachment plugs shall be of a listed grounding type rated 15 or 20 amperes. (c) Support. Flexible cords shall be secured to the undersides of showcases so that (1) wiring will not be exposed to mechanical damage; (2) a separation between cases not in excess of 2 inches (50.8 mm), nor more than 12 inches (305 mm) between the first case and the supply receptacle, will be assured; and (3) the free lead at the end of a group of showcases will have a female fitting not extending beyond the case. (d) No Other Equipment. Equipment other than showcases shall not be electrically connected to showcases. (e) Secondary Circuit(s). Where showcases are cord-connected, the secondary circuit(s) of each electric-discharge lighting ballast shall be limited to one showcase. 410-30. Cord-Connected Lampholders and Fixtures. (a) Lampholders. Where a metal lampholder is attached to a flexible cord, the inlet shall be equipped with an insulating bushing that, if threaded, shall not be smaller than nominal ³/₈-inch pipe size. The cord hole shall be of a size appropriate for the cord, and all burrs and fins shall be removed in order to provide a smooth bearing surface for the cord. Bushing having holes 9/32 inch (7.14 mm) in diameter shall be permitted for use with plain pendant cord and holes ¹³/₃₂ inch (10.3 mm) in diameter with reinforced cord. (b) Adjustable Fixtures. Fixtures that require adjusting or aiming after installation shall not be required to be equipped with an attachment plug or cord connector provided the exposed cord is of the hard usage or extrahard usage type and is not longer than that required for maximum adjustment. The cord shall not be subject to strain or physical damage. (c) Electric-Discharge Fixtures. (1) A listed fixture or a listed fixture assembly shall be permitted to be cord-connected if located directly below the outlet box and the cord is continuously visible for its entire length outside the fixture and is not subject to strain or physical damage. Such cord-equipped fixtures shall terminate at the outer end of the cord in a grounding-type attachment plug (cap) or busway plug. Exception: A listed fixture or a listed fixture assembly incorporating cord and canopy shall not be required to terminate at the outer end in an attachment plug or busway plug. (2) Electric-discharge lighting fixtures provided with mogul-base, screw-shell lampholders shall be permitted to be connected to branch circuits of 50 amperes or less by cords complying with Section 240-4. Receptacles and attachment plugs shall be permitted to be of lower ampere rating than the branch circuit but not less than 125 percent of the fixture fullload current. (3) Electric-discharge lighting fixtures equipped with a flanged surface inlet shall be permitted to be supplied by cord pendants equipped with cord 70-340 NATIONAL ELECTRICAL CODE connectors. Inlets and connectors shall be permitted to be of lower ampere rating than the branch circuit but not less than 125 percent of the fixture load current. 410-31. Fixtures as Raceways. Fixtures shall not be used as a raceway for circuit conductors. Exception No. 1: Fixtures listed for use as a raceway. Exception No. 2: Fixtures designed for end-to-end assembly to form a continuous raceway or fixtures connected together by recognized wiring methods shall be permitted to carry through conductors of a 2-wire or multiwire branch circuit supplying the fixtures. Exception No. 3: One additional 2-wire branch circuit separately supplying one or more of the connected fixtures described in Exception No. 2 shall be permitted to be carried through the fixtures. (FPN): See Article 100 for definition of "Multiwire Branch Circuit." Branch-circuit conductors within 3 inches (76 mm) of a ballast within the ballast compartment shall have an insulation temperature rating not lower than 90°C (194°F), such as Types RHH, THW, THHN, THHW, FEP, FEPB, SA, and XHHW. G. Construction of Fixtures 410-34. Combustible Shades and Enclosures. Adequate air space shall be provided between lamps and shades or other enclosures of combustible material. 410-35. Fixture Rating. (a) Marking. All fixtures requiring ballasts or transformers shall be plainly marked with their electrical rating and the manufacturer's name, trademark, or other suitable means of identification. A fixture requiring supply wire rated higher than 90°C (194°F) shall be so marked, in letters ¼ inch (6.35 mm) high prominently displayed on the fixture and shipping carton or equivalent. (b) Electrical Rating. The electrical rating shall include the voltage and frequency and shall indicate the current rating of the unit, including the ballast, transformer, or autotransformer. 410-36. Design and Material. Fixtures shall be constructed of metal, wood, or other material suitable for the application and shall be so designed and assembled as to secure requisite mechanical strength and rigidity. Wiring compartments, including their entrances, shall be such that conductors may be drawn in and withdrawn without physical damage. 410-37. Nonmetallic Fixtures. In all fixtures not made entirely of metal or noncombustible material, wiring compartments shall be lined with metal. Exception: Where armored or lead-covered conductors with suitable fittings are used. ARTICLE 410 - LIGHTING FIXTURES, ETC. 70-341 410-38. Mechanical Strength. (a) Tubing for Arms. Tubing used for arms and stems where provided with cut threads shall not be less than 0.040 inch (0.1 mm) in thickness and where provided with rolled (pressed) threads shall not be less than 0.025 inch (0.635 mm) in thickness. Arms and other parts shall be fastened to prevent turning. (b) Metal Canopies. Metal canopies supporting lampholders, shades, etc., exceeding 8 pounds (3.63 kg), or incorporating attachment-plug receptacles, shall not be less than 0.020 inch (508 micrometers) in thickness. Other canopies shall not be less than 0.016 inch (406 micrometers) if made of steel and not less than 0.020 inch (508 micrometers) if of other metals. (c) Canopy Switches. Pull-type canopy switches shall not be inserted in the rims of metal canopies that are less than 0.025 inch (635 micrometers) in thickness unless the rims are reinforced by the turning of a bead or the equivalent. Pull-type canopy switches, whether mounted in the rims or elsewhere in sheet metal canopies, shall not be located more than 3½ inches (89 mm) from the center of the canopy. Double set-screws, double canopy rings, a screw ring, or equal method shall be used where the canopy supports a pull-type switch or pendant receptacle. The above thickness requirements shall apply to measurements made on finished (formed) canopies. 410-39. Wiring Space. Bodies of fixtures, including portable lamps, shall provide ample space for splices and taps and for the installation of devices, if any. Splice compartments shall be of nonabsorbent, noncombustible material. 410-42. Portable Lamps. (a) General. Portable lamps shall be wired with flexible cord, recognized by Section 400-4, and an attachment plug of the polarized or grounding type. Where used with Edison-base lampholders, the grounded con- I ductor shall be identified and attached to the screw shell and the identified blade of the attachment plug. (b) Portable Handlamps. In addition to the provisions of Section 410- 42(a), portable handlamps shall comply with the following: (1) metal shell, paper-lined lampholders shall not be used; (2) handlamps shall be equipped with a handle of molded composition or other insulating material; (3) handlamps shall be equipped with a substantial guard attached to the lampholder or handle; (4) metallic guards shall be grounded by the means of an equipment grounding conductor run with circuit conductors within the power-supply cord. 410-44. Cord Bushings. A bushing or the equivalent shall be provided where flexible cord enters the base or stem of a portable lamp. The bushing shall be of insulating material unless a jacketed type of cord is used. 410-45. Tests. All wiring shall be free from short circuits and grounds and shall be tested for these defects prior to being connected to the circuit. 70-342 NATIONAL ELECTRICAL CODE 410-46. Live Parts. Exposed live parts within porcelain fixtures shall be suitably recessed and so located as to make it improbable that wires will come in contact with them. There shall be a spacing of at least ½ inch (12.7 mm) between live parts and the mounting plane of the fixture. H. Installation of Lampholders 410-47. Screw-Shell Type. Lampholders of the screw-shell type shall be installed for use as lampholders only. Where supplied by a circuit having a grounded conductor, the grounded conductor shall be connected to the screw shell. 410-48. Double-Pole Switched Lampholders. Where supplied by the ungrounded conductors of a circuit, the switching device of lampholders of the switched type shall simultaneously disconnect both conductors of the circuit. 410-49. Lampholders in Wet or Damp Locations. Lampholders installed in wet or damp locations shall be of the weatherproof type. J. Construction of Lampholders 410-50. Insulation. The outer metal shell and the cap shall be lined with insulating material that shall prevent the shell and cap from becoming a part of the circuit. The lining shall not extend beyond the metal shell more than 1/8 inch (3.17 mm), but shall prevent any current-carrying part of the lamp base from being exposed when a lamp is in the lampholding device. 410-51. Lead Wires. Lead wires, furnished as a part of weatherproof lampholders and intended to be exposed after installation, shall be of approved stranded, rubber-covered conductors not smaller than No. 14 and shall be sealed in place or otherwise made raintight. Exception: No. 18 rubber-covered conductors shall be permitted for candelabra sockets. 410-52. Switched Lampholders. Switched lampholders shall be of such construction that the switching mechanism interrupts the electrical connection to the center contact. The switching mechanism shall also be permitted to interrupt the electrical connection to the screw shell if the connection to the center contact is simultaneously interrupted. K. Lamps and Auxiliary Equipment 410-53. Bases, Incandescent Lamps. An incandescent lamp for general use on lighting branch circuits shall not be equipped with a medium base if rated over 300 watts, nor with a mogul base if rated over 1500 watts. Special bases or other devices shall be used for over 1500 watts. 410-54. Electric-Discharge Lamp Auxiliary Equipment. (a) Enclosures. Auxiliary equipment for electric-discharge lamps shall be enclosed in noncombustible cases and treated as sources of heat. ARTICLE 410 - LIGHTING FIXTURES, ETC. 70-343 (b) Switching. Where supplied by the ungrounded conductors of a circuit, the switching device of auxiliary equipment shall simultaneously disconnect all conductors. 410-55. Arc Lamps. Arc lamps used in theaters shall comply with Section 520-61, and arc lamps used in projection machines shall comply with