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Article 518

Assembly Occupancies

  1. Scope. Except for the assembly occupancies explicitly covered by 520.1, this article covers all buildings or portions of buildings or structures designed or intended for the gathering together of 100 or more persons for such purposes as delibera‐ tion, worship, entertainment, eating, drinking, amusement, awaiting transportation, or similar purposes.
  2. General Classification.
    1. Examples. Assembly occupancies shall include, but not be limited to, the following:
      Armories Exhibition hallsAssembly halls GymnasiumsAuditoriums Mortuary chapelsBowling lanes Multipurpose roomsClub rooms MuseumsConference rooms Places of awaiting transportationCourtrooms Places of religious worshipDance halls Pool roomsDining and drinking Restaurantsfacilities Skating rinks
    2. Multiple Occupancies. Where an assembly occupancy forms a portion of a building containing other occupancies, Article 518 applies only to that portion of the building consid‐ ered an assembly occupancy. Occupancy of any room or space for assembly purposes by less than 100 persons in a building of other occupancy, and incidental to such other occupancy, shall be classified as part of the other occupancy and subject to the provisions applicable thereto.
    3. Theatrical Areas. Where any such building structure, or portion thereof, contains a projection booth or stage platform or area for the presentation of theatrical or musical produc‐ tions, either fixed or portable, the wiring for that area, includ‐ ing associated audience seating areas, and all equipment that is

    used in the referenced area, and portable equipment and wiring for use in the production that will not be connected to permanently installed wiring, shall comply with Article 520.Informational Note: For methods of determining population capacity, see local building code or, in its absence, NFPA 101-2015, Life Safety Code.
  3. Other Articles.
    1. Hazardous (Classified) Areas. Electrical installations in hazardous (classified) areas located in assembly occupancies shall comply with Article 500.
    2. Temporary Wiring. In exhibition halls used for display booths, as in trade shows, the temporary wiring shall be permit‐ ted to be installed in accordance with Article 590. Flexible cables and cords approved for hard or extra-hard usage shall be permitted to be laid on floors where protected from contact by the general public. The ground-fault circuit-interrupter requirements of 590.6 shall not apply. All other ground-fault circuit-interrupter requirements of this Code shall apply.Where ground-fault circuit interrupter protection for personnel is supplied by plug-and-cord-connection to the branch circuit or to the feeder, the ground fault circuit inter‐ rupter protection shall be listed as portable ground fault circuit interrupter protection or provide a level of protection equiva‐ lent to a portable ground fault circuit interrupter, whether assembled in the field or at the factory.Exception: Where conditions of supervision and maintenance ensure that only qualified persons will service the installation, flexible cords or cables identified in Table 400.4 for hard usage or extra-hard usage shall be permitted in cable trays used only for temporary wiring. All cords or cables shall be installed in a single layer. A permanent sign shall be attached to the cable tray at intervals not to exceed 7.5 m (25 ft). The sign shall readCABLE TRAY FOR TEMPORARY WIRING ONLY
    3. Emergency Systems. Control of emergency systems shall comply with Article 700.
  4. Wiring Methods.
    1. General. The fixed wiring methods shall be metal race‐ ways, flexible metal raceways, nonmetallic raceways encased in not less than 50 mm (2 in.) of concrete, Type MI, MC, or AC cable. The wiring method shall itself qualify as an equip‐ ment grounding conductor according to 250.118 or shall contain an insulated equipment grounding conductor sized in accordance with Table 250.122.Exception: Fixed wiring methods shall be as provided in
      1. Audio signal processing, amplification, and reproduction equipment — Article 640
      2. Communications circuits — Article 800
      3. Class 2 and Class 3 remote-control and signaling circuits —Article 725
      4. Fire alarm circuits — Article 760
    2. Nonrated Construction. In addition to the wiring meth‐ ods of 518.4(A), nonmetallic-sheathed cable, Type AC cable, electrical nonmetallic tubing, and rigid nonmetallic conduit shall be permitted to be installed in those buildings or portions thereof that are not required to be of fire-rated construction by the applicable building code.
      Informational Note: Fire-rated construction is the fire-resistive classification used in building codes.
    3. Spaces with Finish Rating. Electrical nonmetallic tubing and rigid nonmetallic conduit shall be permitted to be instal‐ led in club rooms, conference and meeting rooms in hotels or motels, courtrooms, dining facilities, restaurants, mortuary chapels, museums, libraries, and places of religious worship where the following apply:
    1. The electrical nonmetallic tubing or rigid nonmetallic conduit is installed concealed within walls, floors, and ceilings where the walls, floors, and ceilings provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assem‐ blies.
    2. The electrical nonmetallic tubing or rigid nonmetallic conduit is installed above suspended ceilings where the suspended ceilings provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.
    Electrical nonmetallic tubing and rigid nonmetallic conduit are not recognized for use in other space used for environmen‐ tal air in accordance with 300.22(C).Informational Note: A finish rating is established for assemblies containing combustible (wood) supports. The finish rating is defined as the time at which the wood stud or wood joist reaches an average temperature rise of 121°C (250°F) or an individual temperature rise of 163°C (325°F) as measured on the plane of the wood nearest the fire. A finish rating is not intended to represent a rating for a membrane ceiling.
  5. Supply. Portable switchboards and portable power distribution equipment shall be supplied only from listed power outlets of sufficient voltage and ampere rating. Such power outlets shall be protected by overcurrent devices. Such overcurrent devices and power outlets shall not be accessible to the general public. Provisions for connection of an equipment grounding conductor shall be provided. The neutral conductor of feeders supplying solid-state phase control, 3-phase, 4-wire dimmer systems shall be considered a current-carrying conduc‐ tor for purposes of ampacity adjustment. The neutral conduc‐ tor of feeders supplying solid-state sine wave, 3-phase, 4-wire dimming systems shall not be considered a current-carrying conductor for purposes of ampacity adjustment.

Exception: The neutral conductor of feeders supplying systems that use or may use both phase-control and sine-wave dimmers shall be consid‐ ered as current-carrying for purposes of ampacity adjustment.

Informational Note: For definitions of solid-state dimmer types, see 520.2.

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