Article 530

Motion Picture and Television Studios and Similar Locations

Part I. General

  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 in 520.1, and exchanges, factories, laboratories, stages, or a portion of the building in which film or tape more than 22 mm (7∕8 in.) in width is exposed, developed, printed, cut, edited, rewound, repaired, or stored.Informational Note: For methods of protecting against cellulose nitrate film hazards, see NFPA 40-2011, Standard for the Storage and Handling of Cellulose Nitrate Film.
  2. Definitions.

Alternating-Current Power Distribution Box (Alternating- Current Plugging Box, Scatter Box). An ac distribution center

or box that contains one or more grounding-type polarized receptacles that may contain overcurrent protective devices.

Bull Switch. An externally operated wall-mounted safety switch that may or may not contain overcurrent protection and is designed for the connection of portable cables and cords.

Location (Shooting Location). A place outside a motion picture studio where a production or part of it is filmed or recorded.

Location Board (Deuce Board). Portable equipment contain‐ ing a lighting contactor or contactors and overcurrent protec‐ tion designed for remote control of stage lighting.

Motion Picture Studio (Lot). A building or group of buildings and other structures designed, constructed, or permanently altered for use by the entertainment industry for the purpose of motion picture or television production.

Plugging Box. A dc device consisting of one or more 2-pole, 2-wire, nonpolarized, nongrounding-type receptacles intended to be used on dc circuits only.

Portable Equipment. Equipment intended to be moved from one place to another.

Single-Pole Separable Connector. A device that is installed at the ends of portable, flexible, single-conductor cable that is used to establish connection or disconnection between two cables or one cable and a single-pole, panel-mounted separable connector.

Spider (Cable Splicing Block). A device that contains busbars that are insulated from each other for the purpose of splicing or distributing power to portable cables and cords that are terminated with single-pole busbar connectors.

Stage Effect (Special Effect). An electrical or electromechani‐ cal piece of equipment used to simulate a distinctive visual or audible effect such as wind machines, lightning simulators, sunset projectors, and the like.

Stage Property. An article or object used as a visual element in a motion picture or television production, except painted back‐ grounds (scenery) and costumes.

Stage Set. A specific area set up with temporary scenery and properties designed and arranged for a particular scene in a motion picture or television production.

Stand Lamp (Work Light). A portable stand that contains a general-purpose luminaire or lampholder with guard for the purpose of providing general illumination in the studio or stage.

Television Studio or Motion Picture Stage (Sound Stage). A building or portion of a building usually insulated from the outside noise and natural light for use by the entertainment industry for the purpose of motion picture, television, or commercial production.

530.6 Portable Equipment. Portable stage and studio lighting equipment and portable power distribution equipment shall be permitted for temporary use outdoors if the equipment is supervised by qualified personnel while energized and barriered from the general public.


Part II. Stage or Set

  1. Permanent Wiring. The permanent wiring shall be Type MC cable, Type AC cable containing an insulated equip‐ ment grounding conductor sized in accordance with Table 250.122, Type MI cable, or in approved raceways.Exception: Communications circuits; audio signal processing, amplifi‐ cation, and reproduction circuits; Class 1, Class 2, and Class 3 remote- control or signaling circuits and power-limited fire alarm circuits shall be permitted to be wired in accordance with Articles 640, 725, 760, and 800.
  2. Portable Wiring.
    1. Stage Set Wiring. The wiring for stage set lighting and other supply wiring not fixed as to location shall be done with listed hard usage flexible cords and cables. Where subject to physical damage, such wiring shall be listed extra-hard usage flexible cords and cables. Splices or taps in cables shall be permitted if the total connected load does not exceed the maximum ampacity of the cable.
    2. Stage Effects and Electrical Equipment Used as Stage Properties. The wiring for stage effects and electrical equip‐ ment used as stage properties shall be permitted to be wired with single- or multiconductor listed flexible cords or cables if the conductors are protected from physical damage and secured to the scenery by approved cable ties or by insulated staples. Splices or taps shall be permitted where such are made with listed devices and the circuit is protected at not more than 20 amperes.
    3. Other Electrical Equipment. Cords and cables other than extra-hard usage, where supplied as a part of a listed assembly, shall be permitted.
  3. Stage Lighting and Effects Control. Switches used for studio stage set lighting and effects (on the 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, suitably rated, for the control of each contactor shall be located at a distance of not more than 1.8 m (6 ft) from the contactor, in addition to remote-control switches. A single externally operable switch shall be permitted to simultaneously disconnect all the contac‐ tors on any one location board, where located at a distance of not more than 1.8 m (6 ft) from the location board.
  4. Plugging Boxes. Each receptacle of dc plugging boxes shall be rated at not less than 30 amperes.
  5. Enclosing and Guarding Live Parts.
    1. Live Parts. Live parts shall be enclosed or guarded to prevent accidental contact by persons and objects.
    2. Switches. All switches shall be of the externally operable type.
    3. Rheostats. Rheostats shall be placed in approved cases or cabinets that enclose all live parts, having only the operating handles exposed.
    4. Current-Carrying Parts. Current-carrying parts of bull switches, location boards, spiders, and plugging boxes shall be enclosed, guarded, or located so that persons cannot acciden‐ tally come into contact with them or bring conductive material into contact with them.
  6. Portable Luminaires. Portable luminaires and work lights shall be equipped with flexible cords, composition or metal-sheathed porcelain sockets, and substantial guards.Exception: Portable luminaires used as properties in a motion picture set or television stage set, on a studio stage or lot, or on location shall not be considered to be portable luminaires for the purpose of this section.
  7. Portable Arc Lamps.
    1. Portable Carbon Arc Lamps. Portable carbon 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.
    2. Portable Noncarbon Arc Electric-Discharge Lamps. Porta‐ ble noncarbon arc lamps, including enclosed arc lamps, and associated ballasts shall be listed. Interconnecting cord sets and interconnecting cords and cables shall be extra-hard usage type and listed.
  8. Overcurrent Protection — General. Automatic over‐ current 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 530.18(A) through (G). The maximum ampacity allowed on a given conductor, cable, or cord size shall be as given in the applicable tables of Articles 310 and 400.
    1. Stage Cables. Stage cables for stage set lighting shall be protected by means of overcurrent devices set at not more than 400 percent of the ampacity given in the applicable tables of Articles 310 and 400.
    2. 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 loca‐ ted in the substation) having a suitable ampere rating. The overcurrent devices shall be permitted to be multipole or single-pole gang operated. No pole shall be required in the neutral conductor. The overcurrent device setting for each feeder shall not exceed 400 percent of the ampacity of the feeder, as given in the applicable tables of Article 310.
    3. Cable Protection. Cables shall be protected by bushings where they pass through enclosures and shall be arranged so that tension on the cable is not transmitted to the connections. Where power conductors pass through metal, the requirements of 300.20 shall apply.Portable feeder cables shall be permitted to temporarily penetrate fire-rated walls, floors, or ceilings provided that all of the following apply:
      1. The opening is of noncombustible material.
      2. When in use, the penetration is sealed with a temporary seal of a listed firestop material.
      3. When not in use, the opening shall be capped with a material of equivalent fire rating.
    4. 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 percent of the ampacity of the cables between the location boards and the plugging boxes.
    5. Plugging Boxes. Cables and cords supplied through plug‐ ging boxes shall be of copper. Cables and cords smaller than 8 AWG 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 percent of the rated ampacity of the cables or cords as given in the applicable tables of Articles 310 and 400. Plugging boxes shall not be permitted on ac systems.
    6. Alternating-Current Power Distribution Boxes. Alternating-current power distribution boxes used on sound stages and shooting locations shall contain connection recepta‐ cles of a polarized, grounding type.
    7. Lighting. Work lights, stand lamps, and luminaires rated 1000 watts or less and connected to dc plugging boxes shall be 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 breakers on the location boards.
  9. Sizing of Feeder Conductors for Television Studio Sets.
    1. General. It shall be permissible to apply the demand factors listed in Table 530.19(A) to that portion of the maxi‐ mum 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 loca‐ tion boards.
    2. Portable Feeders. A demand factor of 50 percent of maxi‐ mum possible connected load shall be permitted for all porta‐ ble feeders.
  10. Grounding. Type MC cable, Type MI cable, Type AC cable containing an insulated equipment grounding conduc‐ tor, metal raceways, and all non–current-carrying metal parts of appliances, devices, and equipment shall be connected to an equipment grounding conductor. This shall not apply to pend‐ ant and portable lamps, to portable stage lighting and stage sound equipment, or to other portable and special stage equip‐ ment operating at not over 150 volts dc to ground.
  11. Plugs and Receptacles.
    1. Rating. Plugs and receptacles, including cord connectors and flanged surface devices, shall be rated in amperes. The voltage rating of the plugs and receptacles shall not be less than the nominal circuit voltage. Plug and receptacle ampere ratings for ac circuits shall not be less than the feeder or branch-circuit overcurrent device ampere rating. Table 210.21(B)(2) shall not apply.
      Table 530.19(A) Demand Factors for Stage Set Lighting
      imagePortion of Stage Set Lighting Load
    2. Interchangeability. Plugs and receptacles used in portable professional motion picture and television equipment shall be permitted to be interchangeable for ac or dc use on the same premises, provided they are listed for ac/dc use and marked in a suitable manner to identify the system to which they are connected.
  12. Single-Pole Separable Connectors.
    1. General. Where ac single-pole portable cable connectors are used, they shall be listed and of the locking type. Sections 400.14, 406.7, and 406.8 shall not apply to listed single-pole separable connections and single-conductor cable assemblies utilizing listed single-pole separable connectors. Where paral‐ leled sets of current-carrying single-pole separable connectors are provided as input devices, they shall be prominently labeled with a warning indicating the presence of internal parallel connections. The use of single-pole separable connectors shall comply with at least one of the following conditions:
      1. Connection and disconnection of connectors are only possible where the supply connectors are interlocked to the source and it is not possible to connect or disconnect connectors when the supply is energized.
      2. Line connectors are of the listed sequential-interlocking type so that load connectors shall be connected in the following sequence:
        1. Equipment grounding conductor connection
        2. Grounded circuit conductor connection, if provided
        3. Ungrounded conductor connection, and that discon‐ nection shall be in the reverse order
      3. A caution notice shall be provided adjacent to the line connectors, indicating that plug connection shall be in the following order:
        1. Equipment grounding conductor connectors
        2. Grounded circuit-conductor connectors, if provided
        3. Ungrounded conductor connectors, and that discon‐ nection shall be in the reverse order
      The warning sign(s) or label(s) shall comply with 110.21(B).
    2. Interchangeability. Single-pole separable connectors used in portable professional motion picture and television equip‐ ment shall be permitted to be interchangeable for ac or dc use or for different current ratings on the same premises, provided they are listed for ac/dc use and marked in a suitable manner to identify the system to which they are connected.
  13. Branch Circuits. A branch circuit of any size supplying one or more receptacles shall be permitted to supply stage set lighting loads.

The application of 210.8(B)(4) shall not be required.

Part III. 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.


to Which Demand Factor Applied (volt-amperes)

Feeder Demand Factor (%)

First 50,000 or less at 100

From 50,001 to 100,000 at 75

From 100,001 to 200,000 at 60

Remaining over 200,000 at 50

Part IV. 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.

Part V. Cellulose Nitrate Film Storage Vaults

  1. Lamps in Cellulose Nitrate Film Storage Vaults. Lamps in cellulose nitrate film storage vaults shall be installed in rigid luminaires 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.
  2. Electrical Equipment in Cellulose Nitrate Film Storage Vaults. Except as permitted in 530.51, no receptacles, outlets, heaters, portable lights, or other portable electrical equipment shall be located in cellulose nitrate film storage vaults. Electric motors shall be permitted, provided they are listed for the application and comply with Article 500, Class I, Division 2.

Part VI. Substations

  1. Substations. Wiring and equipment of over 1000 volts, nominal, shall comply with Article 490.
  2. Portable Substations. Wiring and equipment in porta‐ ble substations shall conform to the sections applying to instal‐ lations 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 arranged so 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.
  3. Overcurrent Protection of Direct-Current Generators. Three-wire generators shall have overcurrent protection in accordance with 445.12(E).
  4. Direct-Current Switchboards.
  1. General. Switchboards of not over 250 volts dc between conductors, where located in substations or switchboard rooms accessible to qualified persons only, shall not be required to be dead-front.
  2. Circuit Breaker Frames. Frames of dc circuit breakers installed on switchboards shall not be required to be connected to an equipment grounding conductor.