Special Occupancies, Special Equipment, and Special Conditions
Where Chapters 5, 6, and 7 apply
These chapters supplement or modify Chapters 1-4 and take precedence where they conflict. Hazardous locations (Articles 500-506) classify by Class I (flammable gases), Class II (combustible dust), and Class III (fibers), then by Division or Zone; wiring methods, sealing fittings, and equipment marking follow the classification. Health care facilities (517) divide the essential electrical system into life safety, critical, and equipment branches. Other frequently tested articles: 518 places of assembly, 520 theaters, 550 mobile homes, 551 RV parks, 555 marinas, 590 temporary installations, 680 pools, 690 solar photovoltaic, 695 fire pumps, 700 emergency systems, 701 legally required standby, 702 optional standby, 705 interconnection, 708 critical operations power systems, 760 fire alarm, and 800 communications.
For swimming pools, 680 requires bonding of metal parts and the water (680.26), GFCI protection and distance limits for receptacles (680.22), and it restricts overhead conductors with horizontal and vertical clearances (680.8) - read the table rather than guessing.
For solar PV, 690.8 sizes conductors at 125% of 125% of the source current, and 690.12 requires rapid shutdown so conductors within the array boundary drop to a safe voltage quickly after shutdown.
For emergency systems, 700.10 requires physical separation of emergency circuits, 700.12 lists permitted power sources, and 700.32 requires selective coordination.
Worked example: a fire pump must be connected ahead of the main service disconnect (695.4) so a main trip does not disable the pump. Placing the fire pump on an ordinary feeder is the common wrong answer.
Traps: applying Chapter 5 rules only when convenient - they always govern; missing GFCI and bonding requirements around pools; ignoring separation and coordination rules for emergency systems.