Special Occupancies, Special Locations, and Special Equipment
Hazardous locations
Articles 500-506 classify locations by Class (I gases and vapors, II dust, III fibers), Division or Zone, and group. Equipment must be listed and marked for the class, division, and group. Seals, conduit, and wiring methods are prescribed; ordinary boxes and fittings are not permitted. Intrinsically safe circuits must be identified and separated.
Pools, spas, and similar
Article 680 requires equipotential bonding of pool shells, metal fittings, and equipment with a solid 8 AWG copper conductor, GFCI protection for underwater luminaires and most pool pump circuits, and specific receptacle distances from the water’s edge. Receptacles near pools must generally be at least 6 ft from the inside wall.
Other special areas
Article 690 covers PV systems, 625 EV charging, 700-702 emergency and standby systems, 517 health care, 550 mobile homes, 555 marinas, and 590 temporary wiring. Each has its own disconnecting means, labeling, and wiring method rules.
Traps
Assuming a “wet location” label makes equipment suitable for a corrosive Class I location; forgetting that pool bonding conductors are solid 8 AWG; mixing emergency, legally required, and optional standby requirements; and applying dwelling rules to a marina or RV park.
Worked example
A single-family pool with a 240 V pump: the pump circuit needs GFCI protection, and the pool must have an equipotential bonding grid bonded with 8 AWG solid copper to the pump, ladder, and any metal parts. The bonding conductor is not an equipment grounding conductor and is not sized from Table 250.122.