Special Equipment
What to master
Articles 600 through 712 cover equipment with its own rules: electric signs (600), cranes (610), elevators (620), electric vehicle charging (625), welders (630), IT equipment (645), pools and spas (680), solar photovoltaic systems (690), wind (694), fire pumps (695), energy storage (706), and microgrids (712). Photovoltaic work is tested heavily: 690.7 for maximum system voltage with temperature correction, 690.8 requiring 125% factors on current, 690.9 for OCPD, and 690.12 rapid shutdown, which requires the conductors inside a building to drop to 30 V or less within 30 seconds. Pool work centers on 680.26 equipotential bonding - an 8 AWG solid copper bonding conductor and a grid around the pool perimeter.
Traps
Forgetting the 125% factor applied twice (continuous current plus 125% for OCPD) in PV calculations; omitting rapid shutdown; confusing the pool bonding conductor with the equipment grounding conductor; and assuming a fire pump can be supplied through a standard GFCI device.
Worked example
A pool installation requires bonding of the perimeter surfaces within 3 ft of the water's edge, metal fittings, and metal parts of equipment. The bonding conductor is 8 AWG solid copper, run without splices except at listed connectors, and it is not the same conductor as the 680.26(C) equipment grounding conductor.