Reprinted with permission from NFPA 70-1990 the National Electrical Code (r). (C) 1989, National Fire Protection Association, Quincy, MA. 02269. This reprinted material is NOT the official position of the NFPA, which is represented only by the standard in its entirety. NEC (r) and National Electrical Code (r) are registered trademarks of the NFPA. This information is reprinted here for informational use only. It is not intended to be a definitive statement of what is or is not legal or recognized by the NFPA. Formal interpretations of the Code are available, in writing, by request. Write to: Secretary, Standards Council. National Fire Prevention Association Batterymarch Park Quincy, MA. 02269 If you are requesting formal interpretation, be sure to include the Section and Paragraph numbers you wish interpreted as well as any other information relevant to the issue. ------------------------------------------------------------------------------ This is the COMPLETE text of Article 530. The sections dealing specifically with cables and portable feeders are: 530-12; 530-18; 530-19, and 530-20. ------------------------------------------------------------------------------ A. GENERAL 530-1. SCOPE. The requirements of this article shall apply to television studios and motion picture studios using either film or electronic cameras, except as provided by Section 520-1, and exchanges, factories, laboratories, stages, or a portion of the building in which film or tape more than 7/8" (22mm) in width is exposed, developed, printed, cut, edited, rewound, repaired or stored. (FPN): For methods of protecting against cellulose nitrate film hazards, see Storage & Handling of Cellulose Nitrate Motion Picture Film, NFPA 40-1988 (ANSI) B. STAGE or SET 530-11. PERMANENT WIRING. The permanent wiring shall be Type MC cable, Type MI cable, or in approved raceways. | EXCEPTION: Communications circuits, sound recording and reproducing | circuits, Class 2 and Class 3 remote-control or signaling circuits and | power-limited fire protective signaling circuits shall be permitted to be | wired in accordance with Articles 640, 725, 760, and 800. 530-12. PORTABLE WIRING. The wiring for stage set lighting, stage effects, electric equipment used as stage properties, and other wiring not fixed as to location shall be done with approved flexible cords and cables. Splices or taps shall be permitted in flexible cords used to supply stage properties when such are made with approved devices and the circuit is protected at not more than 20 amperes. Such cords and cables shall not be fastened by staples or nailing. 530-13. STAGE LIGHTING and EFFECTS CONTROL. Switches used for studio set lighting and effects (on stages and lots and on location) shall be of the externally operable type. Where contactors are used as the disconnecting means for fuses, an individual externally operable switch, such as a tumbler switch, for the control of each contactor shall be located at a distance of not more than 6' (1.83m) from the contactor, in addition to remote-control switches. | EXCEPTION: A single externally operable switch shall be permitted to | simultaneously disconnect all the contactors on any one location board, | where located at a distance of not more than 6' (1.83m) from the location | board. 530-14. PLUGGING BOXES. Each receptacle of DC plugging boxes shall be rated at not less than 30 amperes. 530-15. ENCLOSING and GUARDING LIVE PARTS. (a) LIVE PARTS. Live parts shall be enclosed or guarded to prevent accidental contact by persons and objects. (b) SWITCHES. All switches shall be of the externally operable type. (c) RHEOSTATS. Rheostats shall be placed in approved cases or cabinets that enclose all live parts, having only the operating handles exposed. (d) CURRENT-CARRYING PARTS. Current-carrying parts of bull-switches, location boards, spiders, and plugging boxes shall be so enclosed, guarded or located that persons cannot accidentally come into contact with them or bring conductive material into contact with them. 530-16. PORTABLE LAMPS. Portable lamps and work lights shall be equipped with flexible cords, composition or metal-sheathed porcelain sockets and substantial guards. | EXCEPTION: Portable lamps used as properties in a motion picture set or | television stage set, on a studio stage or lot, or on location. 530-17. PORTABLE ARC LAMPS. Portable arc lamps shall be substantially constructed. The arc shall be provided with an enclosure designed to retain sparks and carbons and to prevent persons or materials from coming into contact with the arc or bare live parts. The enclosures shall be ventilated. All switches shall be of the externally operable type. 530-18. OVERCURRENT PROTECTION -- SHORT-TIME RATING. (*) GENERAL. Automatic overcurrent protective devices (circuit breakers or fuses) for motion picture studio stage set lighting and the stage cables for such stage set lighting shall be as given in (a) through (e) below. (FPN): NOTE:(*) Special consideration is given to motion picture studios and similar locations because filming periods are of short duration of 20 minutes. (a) STAGE CABLES. Stage cables for stage set lighting shall be protected by means of overcurrent devices set at not more than 400% of the ampacity given in applicable tables of Articles 310 & 400. (b) FEEDERS. In buildings used primarily for motion picture production, the feeders from the substations to the stages shall be protected by means of overcurrent devices (generally located in the substation) having suitable ampere rating. The overcurrent devices shall be permitted to be multipole or single-pole gang-operated. No pole or overcurrent device shall be required in the neutral conductor. The overcurrent device setting for each feeder shall not exceed 400% of the ampacity of the feeder, as given in applicable tables in Article 310. Short-term ratings shall not be permitted when equipment is operated for periods in excess of 20 minutes. (c) LOCATION BOARDS. Overcurrent protection (fuses or circuit breakers) shall be provided at the "location boards." Fuses in the "location boards" shall have an ampere rating of not over 400% of the ampacity of the cables between the "location boards" and the plugging boxes. (d) PLUGGING BOXES. Cables and cords supplied through plugging boxes shall be of copper. Cables and cords smaller than No. 8 shall be attached to the plugging box by means of a plug containing two cartridge fuses or a 2-pole circuit breaker. The rating of the fuses or the setting of the circuit breaker shall not be over 400% of the ampacity given in applicable tables of Articles 310 & 400. Plugging boxes shall not be permitted on AC systems. (e) LIGHTING. Work lights, stand lamps, and fixtures shall be connected to plugging boxes by means of plugs containing two cartridge fuses not larger than 20 amperes, or they shall be permitted to be connected to special outlets on circuits protected by fuses or circuit breakers rated at not over 20 amperes. Plug fuses shall not be used unless they are on the load side of the fuse or circuit breaker on the "location boards." 530-19. SIZING of FEEDER CONDUCTORS for TELEVISION STUDIO SETS. (a) GENERAL. It shall be permitted to apply the demand factors listed in Table 530-19(a) to that portion of the maximum possible connected load for studio or stage set lighting for all permanently installed feeders between substations and stages and to all permanently installed feeders between the main stage switchboard and stage distribution centers or location boards. -------------------------------------------------------------------- TABLE 530-19(a) DEMAND FACTORS FOR STAGE SET LIGHTING -------------------------------------------------------------------- Portion of Stage Set Lighting Load Feeder Demand to Which Demand Factor Applies Factor (Volt-Amperes) -------------------------------------------------------------------- First 50,000 or less at 100 % More than 50,000 to 100,000 75 % More than 100,000 to 200,000 60 % All over 200,000 50 % -------------------------------------------------------------------- (b) PORTABLE FEEDERS. A demand factor of 50% of maximum possible connected load shall be permitted for all portable feeders. 530-20. GROUNDING. Type MC cable, Type MI cable, metal raceways, and all noncurrent-carrying metal parts of appliances, devices, and equipment shall be grounded as specified in Article 250. This shall not apply to pendant and portable lamps, to stage lighting and stage sound equipment, nor to other portable and special stage equipment operating at not over 150 volts DC to ground. 530-21. PLUGS and RECEPTACLES. Plugs and receptacles shall be rated in amperes. All AC plugs and receptacles shall be of the grounding type. C. DRESSING ROOMS 530-31. DRESSING ROOMS. Fixed wiring in dressing rooms shall be installed in accordance with the wiring methods covered in Chapter 3. Wiring for portable dressing rooms shall be approved. D. VIEWING, CUTTING and PATCHING TABLES 530-41. LAMPS at TABLES. Only composition or metal-sheathed, porcelain, keyless lampholders equipped with suitable means to guard lamps from physical damage and from film and film scrap shall be used at patching, viewing, and cutting tables. E. CELLULOSE NITRATE FILM STORAGE VAULTS 530-51. LAMPS in CELLULOSE NITRATE FILM STORAGE VAULTS. Lamps in cellulose nitrate film storage vaults shall be installed in rigid fixtures of the glass enclosed and gasketed type. Lamps shall be controlled by a switch having a pole in each ungrounded conductor. This switch shall be located outside of the vault and provided with a pilot light to indicate whether the switch is on or off. This switch shall disconnect from all sources of supply all ungrounded conductors terminating in any outlet in the vault. 530-52. MOTORS and OTHER EQUIPMENT in CELLULOSE NITRATE FILM STORAGE VAULTS. Except as permitted in Section 530-51, no receptacles, outlets, electric motors, heaters, portable lights, or other portable electric equipment shall be located in cellulose nitrate film storage vaults. F. SUBSTATIONS 530-61. SUBSTATIONS. Wiring and equipment over 600 volts, nominal, shall comply with Article 710. 530-62. LOW-VOLTAGE SWITCHBOARDS. On 600 volts, nominal, or less, switchboards shall comply with Article 384. 530-63. OVERCURRENT PROTECTION of DC GENERATORS. Three-wire DC generators shall have protection consisting of overcurrent devices having a rating or setting in accordance with the generator ampere rating. Single-pole or double-pole overcurrent devices shall be permitted, and no pole or overcurrent coil shall be required shall be required in the neutral lead (whether it is grounded or ungrounded). 530-64. WORKING SPACE and GUARDING. Working space and guarding in permanent fixed substations shall comply with Sections 110-16 and 110-17. (FPN): For guarding of live parts on motors and generators, see Sections 430-11 and 430-14. | EXCEPTION: Switchboards of not over 250 volts DC between conductors, when | located in substations or switchboard rooms accessible to qualified | persons only, shall not be required to be dead-front. 530-65. PORTABLE SUBSTATIONS. Wiring and equipment in portable substations shall conform to the sections applying to installations in permanently fixed substations, but, due to the limited space available, the working spaces shall be permitted to be reduced, provided that the equipment shall be so arranged that the operator can work safely, and so that other persons in the vicinity cannot accidentally come into contact with current-carrying parts or bring conducting objects into contact with them while they are energized. 530-66. GROUNDING at SUBSTATIONS. Noncurrent-carrying metal parts shall be grounded in accordance with Article 250. | EXCEPTION: Frames of DC circuit breakers installed on switchboards. *** end of file. CODE.530