Article 518 provides the requirements for auditoriums, conference rooms, museums, restaurants, and other places where 100 or more people might gather [518.1, 518.2]. Excluded from Art. 518 are places such as theaters and the audience areas for performances; those are covered by Art. 520.
Portable switchboards and portable power distribution equipment must be supplied only from listed power outlets, and those outlets must be protected by overcurrent devices that aren’t accessible to the public [518.5].
What kinds of wiring methods can you use? Generally, if non-metallic raceways are used as fixed wiring methods, they must be encased in at least 2 in. of concrete [518.4(A)] and must contain an equipment grounding conductor (EGC). The other generally permissible raceways and cables are metallic; the metal raceway or metal cable (Type MI, MC, or AC) can itself serve as the EGC.
Nonmetallic tubing, conduit, or cable can be used in specific applications, as listed in Sec. 518.4(B) and (C). For example, you can use certain non-metallic wiring methods (including rigid nonmetallic conduit and electrical nonmetallic tubing) in buildings (or portions thereof) that aren’t required to be fire-rated.
