Equipment for General Use and Utilization Equipment
The articles that cover real equipment
This domain runs from Article 400 through Article 480: flexible cords (400), switches (404), receptacles (406), panelboards (408), luminaires (410), appliances (422), fixed electric space heating (424), motors (430), air conditioning and refrigeration (440), generators (445), transformers (450) and batteries (480).
Motor rules score the most points
430.6(A) requires the horsepower tables (430.247 through 430.250), not the nameplate current, for sizing branch-circuit conductors, short-circuit and ground-fault protection, and disconnecting means. Nameplate current is used only for running overload protection under 430.32. Branch conductors are 125 percent of table full-load current (430.22). Feeder sizing (430.24) is 125 percent of the largest motor plus 100 percent of the others. 430.52 allows the next higher standard device for an inverse-time breaker but not above the table maximum. Hermetic refrigerant compressors follow 440.22, generally 175 percent of rated-load current with an absolute ceiling of 225 percent.
Appliances and equipment
GFCI requirements for dwellings appear in 210.8 and for specific appliances in 422.5. 440.14 requires the disconnecting means for an air conditioner within sight and within 50 feet.
Traps
Sizing a motor branch circuit from nameplate amps; forgetting the 125 percent on the largest motor at a feeder; assuming 210.8(A) applies to a commercial kitchen (that is 210.8(B)); confusing transformer primary-only protection with primary and secondary protection in Table 450.3(B).
Worked example
A 1 hp, 230 V single-phase motor. Table 430.248 gives 8 A. Branch conductors must carry at least 125 percent, or 10 A, so 14 AWG copper works. The branch breaker is then selected from 430.52, and the running overload is set from the nameplate current per 430.32.