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Article 520

Theaters, Audience Areas of Motion Picture and Television Studios, Performance Areas, and Similar Locations

Part I. General

  1. Scope. This article covers all buildings or that part of a building or structure, indoor or outdoor, designed or used for presentation, dramatic, musical, motion picture projection, or similar purposes and to specific audience seating areas within motion picture or television studios.
  2. Definitions.imageNAdapter. A device used to adapt a circuit from one configura‐ tion of an attachment plug or receptacle to another configura‐ tion with the same current rating.Border Light. A permanently installed overhead strip light.Breakout Assembly. An adapter used to connect a multipole connector containing two or more branch circuits to multiple individual branch-circuit connectors.Bundled. Cables or conductors that are tied, wrapped, taped, or otherwise periodically bound together.Connector Strip. A metal wireway containing pendant or flush receptacles.Drop Box. A box containing pendant- or flush-mounted recep‐ tacles attached to a multiconductor cable via strain relief or a multipole connector.Footlight. A border light installed on or in the stage.Grouped. Cables or conductors positioned adjacent to one another but not in continuous contact with each other.Performance Area. The stage and audience seating area associ‐ ated with a temporary stage structure, whether indoors or outdoors, constructed of scaffolding, truss, platforms, or similar devices, that is used for the presentation of theatrical or musi‐ cal productions or for public presentations.Portable Equipment. Equipment fed with portable cords or cables intended to be moved from one place to another.Portable Power Distribution Unit. A power distribution box containing receptacles and overcurrent devices.Proscenium. The wall and arch that separates the stage from the auditorium (house).Solid-State Phase-Control Dimmer. A solid-state dimmer where the wave shape of the steady-state current does not follow the wave shape of the applied voltage, such that the wave shape is nonlinear.Solid-State Sine Wave Dimmer. A solid-state dimmer where the wave shape of the steady-state current follows the wave shape of the applied voltage such that the wave shape is linear.Stage Equipment. Equipment at any location on the premises integral to the stage production including, but not limited to, equipment for lighting, audio, special effects, rigging, motion control, projection, or video.
    Stage Lighting Hoist. A motorized lifting device that contains a mounting position for one or more luminaires, with wiring devices for connection of luminaires to branch circuits, and integral flexible cables to allow the luminaires to travel over the lifting range of the hoist while energized.Stage Switchboard. A permanently installed switchboard, panelboard, or rack containing dimmers or relays with associ‐ ated overcurrent protective devices, or overcurrent protective devices alone, used primarily to feed stage equipment.imageNStage Switchboard, Portable. A portable rack or pack contain‐ ing dimmers or relays with associated overcurrent protective devices, or overcurrent protective devices alone that are used to feed stage equipment.Stand Lamp (Work Light). A portable stand that contains a general-purpose luminaire or lampholder with guard for the purpose of providing general illumination on the stage or in the auditorium.Strip Light. A luminaire with multiple lamps arranged in a row.Two-Fer. An assembly containing one male plug and two female cord connectors used to connect two loads to one branch circuit.
  3. Motion Picture Projectors. Motion picture equipment and its installation and use shall comply with Article 540.
  4. Audio Signal Processing, Amplification, and Reproduc‐ tion Equipment. Audio signal processing, amplification, and reproduction equipment and its installation shall comply with Article 640.
  5. Wiring Methods.
    1. General. The fixed wiring method shall be metal race‐ ways, nonmetallic raceways encased in at least 50 mm (2 in.) of concrete, Type MI cable, MC cable, or AC cable containing an insulated equipment grounding conductor sized in accordance with Table 250.122.Exception: Fixed wiring methods shall be as provided in Article 640 for audio signal processing, amplification, and reproduction equipment, in Article 800 for communications circuits, in Article 725 for Class 2 and Class 3 remote-control and signaling circuits, and in Article 760 for fire alarm circuits.
    2. Portable Equipment. The wiring for portable switch‐ boards, stage set lighting, stage effects, and other wiring not fixed as to location shall be permitted with approved flexible cords and cables as provided elsewhere in Article 520. Fasten‐ ing such cables and cords by uninsulated staples or nailing shall not be permitted.
    3. Nonrated Construction. Nonmetallic-sheathed cable, Type AC cable, electrical nonmetallic tubing, and rigid nonme‐ tallic conduit shall be permitted to be installed in those build‐ ings or portions thereof that are not required to be of fire-rated construction by the applicable building code.
  6. Number of Conductors in Raceway. The number of conductors permitted in any metal conduit, rigid nonmetallic conduit as permitted in this article, or electrical metallic tubing for circuits or for remote-control conductors shall not exceed the percentage fill shown in Table 1 of Chapter 9. Where contained within an auxiliary gutter or a wireway, the sum of the cross-sectional areas of all contained conductors at any cross section shall not exceed 20 percent of the interior cross-sectional area of the auxiliary gutter or wireway. The 30- conductor limitation of 366.22 and 376.22 shall not apply.
  7. Enclosing and Guarding Live Parts. Live parts shall be enclosed or guarded to prevent accidental contact by persons and objects. All switches shall be of the externally operable type. Dimmers, including rheostats, shall be placed in cases or cabinets that enclose all live parts.
  8. Emergency Systems. Control of emergency systems shall comply with Article 700.
  9. Branch Circuits. A branch circuit of any size supplying one or more receptacles shall be permitted to supply stage set lighting. The voltage rating of the receptacles shall be not less than the circuit voltage. Receptacle ampere ratings and branch- circuit conductor ampacity shall be not less than the branch- circuit overcurrent device ampere rating. Table 210.21(B)(2) and 210.23 shall not apply. The application of 210.8(B)(4) shall not be required.
  10. Portable Equipment Used Outdoors. Portable stage and studio lighting equipment and portable power distribution equipment not identified for outdoor use shall be permitted for temporary use outdoors, provided the equipment is super‐ vised by qualified personnel while energized and barriered from the general public.

Part II. Fixed Stage Switchboards

520.21 General. Fixed stage switchboards shall comply with 520.21(1) through (4):

  1. Fixed stage switchboards shall be listed.
  2. Fixed stage switchboards shall be readily accessible but shall not be required to be located on or adjacent to the stage. Multiple fixed stage switchboards shall be permit‐ ted at different locations.
  3. A fixed stage switchboard shall contain overcurrent protective devices for all branch circuits supplied by that switchboard.
  4. A fixed stage switchboard shall be permitted to supply both stage and non-stage equipment.
  1. Dimmers. Dimmers shall comply with 520.25(A) through (D).
    1. Disconnection and Overcurrent Protection. Where dimmers are installed in ungrounded conductors, each dimmer shall have overcurrent protection not greater than 125 percent of the dimmer rating and shall be disconnected from all ungrounded conductors when the master or individual switch or circuit breaker supplying such dimmer is in the open position.
    2. Resistance- or Reactor-Type Dimmers. Resistance- or series reactor-type dimmers shall be permitted to be placed in either the grounded or the ungrounded conductor of the circuit. Where designed to open either the supply circuit to the dimmer or the circuit controlled by it, the dimmer shall then comply with 404.2(B). Resistance- or reactor-type dimmers placed in the grounded neutral conductor of the circuit shall not open the circuit.
    3. Autotransformer-Type Dimmers. The circuit supplying an autotransformer-type dimmer shall not exceed 150 volts between conductors. The grounded conductor shall be common to the input and output circuits.
      Informational Note: See 210.9 for circuits derived from auto‐ transformers.
    4. Solid-State-Type Dimmers. The circuit supplying a solid- state dimmer shall not exceed 150 volts between conductors unless the dimmer is listed specifically for higher voltage opera‐ tion. Where a grounded conductor supplies a dimmer, it shall be common to the input and output circuits. Dimmer chassis shall be connected to the equipment grounding conductor.
  2. Type of Switchboard. A stage switchboard shall be either one or a combination of the types specified in 520.26(A), (B), (C), and (D).
    1. Manual. Dimmers and switches are operated by handles mechanically linked to the control devices.
    2. Remotely Controlled. Devices are operated electrically from a pilot-type control console or panel. Pilot control panels either shall be part of the switchboard or shall be permitted to be at another location.
    3. Intermediate. A stage switchboard with circuit intercon‐ nections is a secondary switchboard (patch panel) or panel‐ board remote to the primary stage switchboard. It shall contain overcurrent protection. Where the required branch-circuit overcurrent protection is provided in the dimmer panel, it shall be permitted to be omitted from the intermediate switch‐ board.
    4. Constant Power. A stage switchboard containing only overcurrent protective devices and no control elements.
  3. Stage Switchboard Feeders.
  1. Type of Feeder. Feeders supplying stage switchboards shall be one of the types in 520.27(A)(1) through (A)(3).
    1. Single Feeder. A single feeder disconnected by a single disconnect device.
    2. Multiple Feeders to Intermediate Stage Switchboard (Patch Panel). Multiple feeders of unlimited quantity shall be permit‐ ted, provided that all multiple feeders are part of a single system. Where combined, neutral conductors in a given race‐ way shall be of sufficient ampacity to carry the maximum unbal‐ anced current supplied by multiple feeder conductors in the same raceway, but they need not be greater than the ampacity of the neutral conductor supplying the primary stage switch‐ board. Parallel neutral conductors shall comply with 310.10(H).
    3. Separate Feeders to Single Primary Stage Switchboard (Dimmer Bank). Installations with separate feeders to a single primary stage switchboard shall have a disconnecting means for each feeder. The primary stage switchboard shall have a perma‐ nent and obvious label stating the number and location of disconnecting means. If the disconnecting means are located in more than one distribution switchboard, the primary stage switchboard shall be provided with barriers to correspond with these multiple locations.
  2. Neutral Conductor. For the purpose of ampacity adjust‐ ment, the following shall apply:
    1. The neutral conductor of feeders supplying solid-state, phase-control 3-phase, 4-wire dimming systems shall be considered a current-carrying conductor.
    2. The neutral conductor of feeders supplying solid-state, sine wave 3-phase, 4-wire dimming systems shall not be considered a current-carrying conductor.
    3. The neutral conductor of feeders supplying systems that use or may use both phase-control and sine wave dimmers shall be considered as current-carrying.
  3. Supply Capacity. For the purposes of calculating supply capacity to switchboards, it shall be permissible to consider the maximum load that the switchboard is intended to control in a given installation, provided that the following apply:
  1. All feeders supplying the switchboard shall be protected by an overcurrent device with a rating not greater than the ampacity of the feeder.
  2. The opening of the overcurrent device shall not affect the proper operation of the egress or emergency lighting systems.

Informational Note: For calculation of stage switchboard feeder loads, see 220.40.

Part III. Fixed Stage Equipment Other Than Switchboards

  1. Stage Lighting Hoists. Where a stage lighting hoist is listed as a complete assembly and contains an integral cable- handling system and cable to connect a moving wiring device to a fixed junction box for connection to permanent wiring, the extra-hard usage requirement of 520.44(C)(1) shall not apply.
  2. Circuit Loads.
    1. Circuits Rated 20 Amperes or Less. Footlights, border lights, and proscenium sidelights shall be arranged so that no branch circuit supplying such equipment carries a load exceed‐ ing 20 amperes.
    2. Circuits Rated Greater Than 20 Amperes. Where only heavy-duty lampholders are used, such circuits shall be permit‐ ted to comply with Article 210 for circuits supplying heavy-duty lampholders.
  3. Conductor Insulation. Foot, border, proscenium, or portable strip lights and connector strips shall be wired with conductors that have insulation suitable for the temperature at which the conductors are operated, but not less than 125°C (257°F). The ampacity of the 125°C (257°F) conductors shall be that of 60°C (140°F) conductors. All drops from connector strips shall be 90°C (194°F) wire sized to the ampacity of 60°C (140°F) cords and cables with no more than 150 mm (6 in.) of conductor extending into the connector strip. Section 310.15(B)(3)(a) shall not apply.Informational Note: See Table 310.104(A) for conductor types.
  4. Footlights.
    1. Metal Trough Construction. Where metal trough construction is employed for footlights, the trough containing the circuit conductors shall be made of sheet metal not lighter than 0.81 mm (0.032 in.) and treated to prevent oxidation. Lampholder terminals shall be kept at least 13 mm (1∕2 in.) from the metal of the trough. The circuit conductors shall be soldered to the lampholder terminals.
    2. Other-Than-Metal Trough Construction. Where the metal trough construction specified in 520.43(A) is not used, foot‐ lights shall consist of individual outlets with lampholders wired with rigid metal conduit, intermediate metal conduit, or flexi‐Table 520.44(C)(3) Ampacity of Listed Extra-Hard-Usage Cords and Cables with Temperature Ratings of 75°C (167°F) and 90°C (194°F)* [Based on Ambient Temperature of 30°C (86°F)]ble metal conduit, Type MC cable, or mineral-insulated, metal-                                                                                                                                sheathed cable. The circuit conductors shall be soldered to the lampholder terminals.
      Size (AWG)75°C (167°F)90°C (194°F)Overcurrent Device14242815123235201041472585765356778745410111460213315280
    3. Disappearing Footlights. Disappearing footlights shall be arranged so that the current supply is automatically disconnec‐ ted when the footlights are replaced in the storage recesses designed for them.
  5. Borders, Proscenium Sidelights, Drop Boxes, and Connector Strips.
    1. General. Borders and proscenium sidelights shall be as follows:Temperature Rating of Cords and CablesMaximum Rating of
      1. Constructed as specified in 520.43
      2. Suitably stayed and supported
      3. Designed so that the flanges of the reflectors or other adequate guards protect the lamps from mechanical damage and from accidental contact with scenery or other combustible material
    2. Connector Strips and Drop Boxes. Connector strips and drop boxes shall be as follows:
      1. Suitably stayed and supported
      2. Listed as stage and studio wiring devices
    3. Cords and Cables for Border Lights, Drop Boxes, and
    *Ampacity shown is the ampacity for multiconductor cords and cables where only three copper conductors are current-carrying as described in 400.5. If the number of current-carrying conductors in a cord or cable exceeds three and the load diversity is 50 percent or less, the ampacity of each conductor shall be reduced as shown in the following table:
    Table 520.44(C)(3)(a) Ampacity Adjustment Factors for More Than Three Current-Carrying Conductors in a Cord or Cable Where Load Diversity Is 50% or Less
    imagePercent of Ampacity Value inConnector Strips.Number of ConductorsTable 520.44(C)(3)
    1. General. Cords and cables for supply to border lights, drop boxes, and connector strips shall be listed for extra-hard usage. The cords and cables shall be suitably supported. Such cords and cables shall be employed only where flexible conduc‐ tors are necessary. Ampacity of the conductors shall be as provi‐ ded in 400.5.
    2. Cords and Cables Not in Contact with Heat-Producing Equipment. Listed multiconductor extra-hard-usage-type cords and cables not in direct contact with equipment contain‐ ing heat-producing elements shall be permitted to have their ampacity determined by Table 520.44(C)(3). Maximum load current in any conductor with an ampacity determined by Table 520.44(C)(3) shall not exceed the values in Table 520.44(C)(3) .
    3. Identification of Conductors in Multiconductor Extra- Hard-Usage Cords and Cables. Grounded (neutral) conduc‐ tors shall be white without stripe or shall be identified by a distinctive white marking at their terminations. Grounding conductors shall be green with or without yellow stripe or shall be identified by a distinctive green marking at their termina‐ tions.

    image4–6 807–24 7025–42 6043 and above 50Note: Ultimate insulation temperature. In no case shall conductors be associated together in such a way with respect to the kind of circuit, the wiring method used, or the number of conductors such that the temperature limit of the conductors is exceeded.A neutral conductor that carries only the unbalanced current from other conductors of the same circuit need not be considered as a current-carrying conductor.In a 3-wire circuit consisting of two-phase conductors and the neutral conductor of a 4-wire, 3-phase, wye-connected system, the neutral conductor carries approximately the same current as the line-to-neutral currents of the other conductors and shall be considered to be a current-carrying conductor.On a 4-wire, 3-phase wye circuit where the major portion of the load consists of nonlinear loads, there are harmonic currents in the neutral conductor. Therefore, the neutral conductor shall be considered to be a current-carrying conductor.
    Informational Note: For the purposes of Table 520.44(C)(3)(a),load diversity is the percentage of the total current of all simulta‐ neously energized circuits fed by the cable to the sum of the ampacity ratings of all circuits in that cable.
  6. Receptacles. Receptacles for electrical equipment on stages shall be rated in amperes. Conductors supplying recepta‐ cles shall be in accordance with Articles 310 and 400.
  7. Connector Strips, Drop Boxes, Floor Pockets, and Other Outlet Enclosures. Receptacles for the connection of portable stage-lighting equipment shall be pendant or moun‐ ted in suitable pockets or enclosures and shall comply with520.45. Supply cables for connector strips and drop boxes shall be as specified in 520.44(C).
  8. Backstage Lamps (Bare Bulbs). Lamps (bare bulbs) installed in backstage and ancillary areas where they can come in contact with scenery shall be located and guarded so as to be free from physical damage and shall provide an air space of not less than 50 mm (2 in.) between such lamps and any combusti‐ ble material.Exception: Decorative lamps installed in scenery shall not be considered to be backstage lamps for the purpose of this section.
  9. Curtain Machines. Curtain machines shall be listed.
  10. Smoke Ventilator Control. Where stage smoke ventila‐ tors are released by an electrical device, the circuit operating the device shall be normally closed and shall be controlled by at least two externally operable switches, one switch being placed at a readily accessible location on stage and the other where designated by the authority having jurisdiction. The device shall be designed for the full voltage of the circuit to which it is connected, no resistance being inserted. The device shall be enclosed in a suitable metal box having a door that shall remain closed except during service to the equipment.
    Part IV. Portable Switchboards on Stage
  11. Road Show Connection Panel (A Type of Patch Panel). A panel designed to allow for road show connection of porta‐ ble stage switchboards to fixed lighting outlets by means of permanently installed supplementary circuits. The panel, supplementary circuits, and outlets shall comply with 520.50(A) through (D).
    1. Load Circuits. Circuits shall originate from grounding- type polarized inlets of current and voltage rating that match the fixed-load receptacle.
    2. Circuit Transfer. Circuits that are transferred between fixed and portable switchboards shall have all circuit conduc‐ tors transferred simultaneously.
    3. Overcurrent Protection. The supply devices of these supplementary circuits shall be protected by branch-circuit overcurrent protective devices. Each supplementary circuit, within the road show connection panel and theater, shall be protected by branch-circuit overcurrent protective devices installed within the road show connection panel.
    4. Enclosure. Panel construction shall be in accordance with Article 408.
  12. Supply. Portable switchboards shall be supplied only from power outlets of sufficient voltage and ampere rating. Such power outlets shall include only externally operable, enclosed fused switches or circuit breakers mounted on stage or at the permanent switchboard in locations readily accessible from the stage floor. Provisions for connection of an equip‐ ment grounding conductor shall be provided. For the purposes of ampacity adjustment, the requirements of 520.27(B) shall apply.
  13. Overcurrent Protection for Branch Circuits. Portable switchboards shall contain overcurrent protection for branch circuits. The requirements of 210.23 shall not apply.
  14. Construction. Portable stage switchboards shall be listed and shall comply with 520.53(A) through (E).
  1. Pilot Light. A pilot light shall be provided for each ungrounded conductor feeding the switchboard. The pilot light(s) shall be connected to the incoming feeder so that oper‐ ationof the main overcurrent protective device or master switch shall not affect the operation of the pilot light(s).imageN•
  2. Neutral Terminal. In portable switchboard equipmentdesigned for use with 3-phase, 4-wire with ground supply, the current rating of the supply neutral terminal, and the ampacity of its associated busbar or equivalent wiring, or both, shall have an ampacity equal to at least twice the ampacity of the largest ungrounded supply terminal.Exception: Where portable switchboard equipment is specifically constructed and identified to be internally converted in the field, in an approved manner, from use with a balanced 3-phase, 4-wire with ground supply to a balanced single-phase, 3-wire with ground supply, the supply neutral terminal and its associated busbar, equivalent wiring, or both, shall have an ampacity equal to at least that of the largest ungrounded single-phase supply terminal.imageN
  3. Single-Pole Separable Connectors. Where single-pole portable cable connectors are used on a portable stage switch‐ board, they shall be listed and of the locking type. Sections406.7 and 406.8 shall not apply to listed single-pole separable connectors and single-conductor cable assemblies utilizing listed single-pole separable connectors. Where paralleled sets of current-carrying, single-pole separable connectors are provi‐ ded as input devices, they shall be prominently labeled with a warning indicating the presence of internal parallel connec‐ tions. The use of single-pole separable connectors shall comply with at least one of the following conditions:
    1. Connection and disconnection of connectors are possible only 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).imageN
  4. Supply Feed-Through. Where a portable stage switch‐ board contains a feed-through outlet of the same rating as its supply inlet, the feed-through outlet shall not require overcur‐ rent protection in the switchboard.
  5. Interior Conductors. All conductors other than busbars within the switchboard enclosure shall be stranded.

•

520.54 Supply Conductors.

  1. General. The supply to a portable stage switchboard shall be by means of listed extra-hard usage cords or cables. The supply cords or cables shall terminate within the switchboard enclosure in an externally operable fused master switch or circuit breaker or in an identified connector assembly. The supply cords or cable (and connector assembly) shall have current ratings not less than the total load connected to the switchboard and shall be protected by overcurrent devices.imageN
  2. Conductor Sizing. The power supply conductors for port‐ able stage switchboards utilizing solid-state phase control dimmers shall be sized considering the neutral conductor as a current-carrying conductor for ampacity adjustment purposes. The power supply conductors for portable stage switchboards utilizing only solid-state sine wave dimmers shall be sized considering the neutral conductor as a non–current carrying conductor for ampacity adjustment purposes.
  3. Single-Conductor Cables. Single-conductor portable supply cable sets shall be not smaller than 2 AWG conductors. The equipment grounding conductor shall not be smaller than 6 AWG conductor. Single-conductor grounded neutral cables for a supply shall be sized in accordance with 520.54(J). Where single conductors are paralleled for increased ampacity, the paralleled conductors shall be of the same length and size. Single-conductor supply cables shall be grouped together but not bundled. The equipment grounding conductor shall be permitted to be of a different type, provided it meets the other requirements of this section, and it shall be permitted to be reduced in size as permitted by 250.122. Grounded (neutral) and equipment grounding conductors shall be identified in accordance with 200.6, 250.119, and 310.110. Grounded conductors shall be permitted to be identified by marking at least the first 150 mm (6 in.) from both ends of each length of conductor with white or gray. Equipment grounding conduc‐ tors shall be permitted to be identified by marking at least the first 150 mm (6 in.) from both ends of each length of conduc‐ tor with green or green with yellow stripes. Where more than one nominal voltage exists within the same premises, each ungrounded conductor shall be identified by system.
  4. Supply Conductors Not Over 3 m (10 ft) Long. Where supply conductors do not exceed 3 m (10 ft) in length between supply and switchboard or supply and a subsequent overcur‐ rent device, the supply conductors shall be permitted to be reduced in size where all of the following conditions are met:
    1. The ampacity of the supply conductors shall be at least one-quarter of the current rating of the supply overcur‐ rent protective device.
    2. The supply conductors shall terminate in a single over‐ current protective device that will limit the load to the ampacity of the supply conductors. This single overcur‐ rent device shall be permitted to supply additional over‐ current devices on its load side.
    3. The supply conductors shall not penetrate walls, floors, or ceilings or be run through doors or traffic areas. The supply conductors shall be adequately protected from physical damage.
    4. The supply conductors shall be suitably terminated in an approved manner.
    5. Conductors shall be continuous without splices or connectors.
    6. Conductors shall not be bundled.
    7. Conductors shall be supported above the floor in an approved manner.
  5. Supply Conductors Not Over 6 m (20 ft) Long. Where supply conductors do not exceed 6 m (20 ft) in length between supply and switchboard or supply and a subsequent overcur‐ rent protection device, the supply conductors shall be permit‐ ted to be reduced in size where all of the following conditions are met:
    1. The ampacity of the supply conductors shall be at least one-half of the current rating of the supply overcurrent protective device.
    2. The supply conductors shall terminate in a single over‐ current protective device that limits the load to the ampacity of the supply conductors. This single overcur‐ rent device shall be permitted to supply additional over‐ current devices on its load side.
    3. The supply conductors shall not penetrate walls, floors, or ceilings or be run through doors or traffic areas. The supply conductors shall be adequately protected from physical damage.
    4. The supply conductors shall be suitably terminated in an approved manner.
    5. The supply conductors shall be supported in an approved manner at least 2.1 m (7 ft) above the floor except at terminations.
    6. The supply conductors shall not be bundled.
    7. Tap conductors shall be in unbroken lengths.
  6. Supply Conductors Not Reduced in Size. Supply conduc‐ tors not reduced in size under provisions of 520.54(D) or (E) shall be permitted to pass through holes in walls specifically designed for the purpose. If penetration is through the fire- resistant–rated wall, it shall be in accordance with 300.21.imageN•
  7. Protection of Supply Conductors and Connectors. Allsupply conductors and connectors shall be protected against physical damage by an approved means. This protection shall not be required to be raceways.
  8. Number of Supply Interconnections. Where connectors are used in a supply conductor, there shall be a maximum number of three interconnections (mated connector pairs) where the total length from supply to switchboard does not exceed 30 m (100 ft). In cases where the total length from supply to switchboard exceeds 30 m (100 ft), one additional interconnection shall be permitted for each additional 30 m (100 ft) of supply conductor.
  9. Single-Pole Separable Connectors. Where single-pole port‐ able cable connectors are used, they shall be listed and of the locking type. Sections 406.7 and 406.8 shall not apply to listed single-pole separable connectors and single-conductor cable assemblies utilizing listed single-pole separable connectors.•
  10. Supply Neutral Conductor. Supply neutral conductorsimage(1) Marking. Grounded neutral conductors shall be permit‐ ted to be identified by marking at least the first 150 mm (6 in.) from both ends of each length of conductor with white or gray.shall comply with (1) and (2) below:
    •(2) Conductor Sizing. Where single-conductor feeder cablesnot installed in raceways are used on multiphase circuits feed‐ ing portable stage switchboards containing solid-state phase- control dimmers, the grounded neutral conductor shall have an ampacity of at least 130 percent of the ungrounded circuit
    conductors feeding the portable stage switchboard. Where such feeders are supplying only solid-state sine wave dimmers, the grounded neutral conductor shall have an ampacity of at least 100 percent of the ungrounded circuit conductors feed‐ ing the portable stage switchboard.•
  11. Qualified Personnel. The routing of portable supplyconductors, the making and breaking of supply connectors and other supply connections, and the energization and de- energization of supply services shall be performed by qualified personnel, and portable switchboards shall be so marked, indi‐ cating this requirement in a permanent and conspicuous manner.Exception: A portable switchboard shall be permitted to be connected to a permanently installed supply receptacle by other than qualified personnel provided that the supply receptacle is protected for its current rating by an overcurrent device of not greater than 150 amperes, and where the receptacle, interconnection, and switchboard comply with all of the following:
    1. They employ listed multipole connectors suitable for the purpose for every supply interconnection.
    2. They prevent access to all supply connections by the general public.
    3. They employ listed extra-hard usage multiconductor cords or cables with an ampacity not less than the load and not less than the ampere rating of the connectors.

Part V. Portable Stage Equipment Other Than Switchboards

  1. Arc Lamps. 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.
  2. Portable Power Distribution Units. Portable power distribution units shall comply with 520.62(A) through (F).
    1. Enclosure. The construction shall be such that no current-carrying part will be exposed.
    2. Receptacles and Overcurrent Protection. Receptacles shall comply with 520.45 and shall have branch-circuit overcur‐ rent protection in the box. Fuses and circuit breakers shall be protected against physical damage. Flexible cords or cables supplying pendant receptacles or cord connectors shall be listed for extra-hard usage.
    3. Busbars and Terminals. Busbars shall have an ampacity equal to the sum of the ampere ratings of all the circuits connected to the busbar. Lugs shall be provided for the connection of the master cable.
    4. Flanged Surface Inlets. Flanged surface inlets (recessed plugs) that are used to accept the power shall be rated in amperes.
    5. Cable Arrangement. Cables shall be adequately protected where they pass through enclosures and be arranged so that tension on the cable is not transmitted to the terminations.imageN
    6. Single-Conductor Feeders. Portable power distribution equipment fed by single-conductor feeder systems shall comply with 520.53(C) and (D) and 520.54.
  3. Bracket Fixture Wiring.
    1. Bracket Wiring. Brackets for use on scenery shall be wired internally, and the fixture stem shall be carried through to the back of the scenery where a bushing shall be placed on the end of the stem. Externally wired brackets or other fixtures shall be permitted where wired with cords designed for hard usage that extend through scenery and without joint or splice in canopy of fixture back and terminate in an approved-type stage connector located, where practical, within 450 mm (18 in.) of the fixture.
    2. Mounting. Fixtures shall be securely fastened in place.
  4. Portable Strips. Portable strips shall be constructed in accordance with the requirements for border lights and prosce‐ nium sidelights in 520.44(A). The supply cable shall be protec‐ ted by bushings where it passes through metal and shall be arranged so that tension on the cable will not be transmitted to the connections.Informational Note No. 1: See 520.42 for wiring of portable strips.Informational Note No. 2: See 520.68(A)(3) for insulation types required on single conductors.
  5. Festoons. Joints in festoon wiring shall be staggered. Where such lampholders have terminals of a type that punc‐ ture the insulation and make contact with the conductors, they shall be attached only to conductors of the stranded type. Lamps enclosed in lanterns or similar devices of combustible material shall be equipped with guards.
  6. Special Effects. Electrical devices used for simulating lightning, waterfalls, and the like shall be constructed and loca‐ ted so that flames, sparks, or hot particles cannot come in contact with combustible material.
  7. Multipole Branch-Circuit Cable Connectors. Multipole branch-circuit cable connectors, male and female, for flexible conductors shall be constructed so that tension on the cord or cable is not transmitted to the connections. The female half shall be attached to the load end of the power supply cord or cable. The connector shall be rated in amperes and designed so that differently rated devices cannot be connected together; however, a 20-ampere T-slot receptacle shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Alternating-current multipole connectors shall be polarized and comply with 406.7 and 406.10.Informational Note: See 400.14 for pull at terminals.
  8. Conductors for Portables.
    1. Conductor Type.
      1. General. Flexible conductors, including cable extensions, used to supply portable stage equipment shall be listed extra- hard usage cords or cables.
      2. Stand Lamps. Listed, hard usage cord shall be permitted to supply stand lamps where the cord is not subject to physical damage and is protected by an overcurrent device rated at not over 20 amperes.ARTICLE 522 — CONTROL SYSTEMS FOR PERMANENT AMUSEMENT ATTRACTIONS 522.2
      3. Luminaire Supply Cords. Listed hard usage supply cords shall be permitted to supply luminaires when all of the follow‐ ing conditions are met:
        1. The supply cord is not longer than 2.0 m (6.6 ft).
        2. The supply cord is attached at one end to the luminaire or a luminaire-specific listed connector that mates with a panel-mounted inlet on the body of the luminaire.
        3. The supply cord is protected by an overcurrent protective device of not more than 20 amperes.
        4. The luminaire is listed.
        5. The supply cord is not subject to physical damage.
        1. High-Temperature Applications. A special assembly of conductors in sleeving not longer than 1.0 m (3.3 ft) shall be permitted to be employed in lieu of flexible cord if the individ‐ ual wires are stranded and rated not less than 125°C (257°F) and the outer sleeve is glass fiber with a wall thickness of at least 0.635 mm (0.025 in.).Portable stage equipment requiring flexible supply conduc‐ tors with a higher temperature rating where one end is perma‐ nently attached to the equipment shall be permitted to employ alternate, suitable conductors as determined by a qualified test‐ ing laboratory and recognized test standards.
        2. Breakouts. Listed, hard usage (junior hard service) cords shall be permitted in breakout assemblies where all of the following conditions are met:
        1. The cords are utilized to connect between a single multi‐ pole connector containing two or more branch circuits and multiple 2-pole, 3-wire connectors.
        2. The longest cord in the breakout assembly does not exceed 6.0 m (20 ft).
        3. The breakout assembly is protected from physical damage by attachment over its entire length to a pipe, truss, tower, scaffold, or other substantial support structure.
        4. All branch circuits feeding the breakout assembly are protected by overcurrent devices rated at not over 20 amperes.
    2. Conductor Ampacity. The ampacity of conductors shall be as given in 400.5, except multiconductor, listed, extra-hard usage portable cords that are not in direct contact with equip‐ ment containing heat-producing elements shall be permitted to have their ampacity determined by Table 520.44(C)(3). Maximum load current in any conductor with an ampacity determined by Table 520.44(C)(3) shall not exceed the values in Table 520.44(C)(3). Where the ampacity adjustment factors of Table 520.44(C)(3)(a) are applied for more than three current-carrying conductors in a portable cord, the load diver‐ sity shall be 50 percent or less.Exception: Where alternate conductors are allowed in 520.68(A)(4), their ampacity shall be as given in the appropriate table in this Code for the types of conductors employed.imageN
    3. Overcurrent Protection. Overcurrent protection of conductors for portables shall comply with 240.5.
  9. Adapters. Adapters, two-fers, and other single- and multiple-circuit outlet devices shall comply with 520.69(A), (B), and (C).
  1. No Reduction in Current Rating. Each receptacle and its corresponding cable shall have the same current and voltage rating as the plug supplying it. It shall not be utilized in a stage circuit with a greater current rating.
  2. Connectors. All connectors shall be wired in accordance with 520.67.
  3. Conductor Type. Conductors for adapters and two-fers shall be listed extra-hard usage or listed hard usage (junior hard service) cord. Hard usage (junior hard service) cord shall be restricted in overall length to 2.0 m (6.6 ft).

Part VI. Dressing Rooms, Dressing Areas, and Makeup Areas.

  1. Pendant Lampholders. Pendant lampholders shall not be installed in dressing or makeup rooms.
  2. Lamp Guards. All exposed lamps in dressing or makeup areas including rooms where they are less than 2.5 m (8 ft) from the floor shall be equipped with open-end guards riveted to the outlet box cover or otherwise sealed or locked in place. Recessed lamps shall not be required to be equipped with guards.
  3. Switches Required. All luminaires, lampholders, and any receptacles adjacent to the mirror(s) and above the dress‐ ing or makeup counter(s) installed in dressing or makeup rooms shall be controlled by wall switches installed in the dress‐ ing or makeup room(s). Other outlets installed in the dressing or makeup rooms shall not be required to be switched.imageN
  4. Pilot Lights Required. Each switch required in 520.73 shall be provided with a pilot light located outside of and adja‐ cent to the door of the room being controlled to indicate when the circuit is energized. Each pilot light shall be permanently identified indicating a description of the circuit controlled. Pilot lights shall be neon, LED, or other extended-life lamp. Pilot lights shall be recessed or provided with a mechanical guard.

Part VII. Grounding

520.81 Grounding. All metal raceways and metal-sheathed cables shall be connected to an equipment grounding conduc‐ tor. The metal frames and enclosures of all equipment, includ‐ ing border lights and portable luminaires, shall be connected to an equipment grounding conductor.

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