Feeder for a Group of Motors (NEC 430.24 / 430.62)
The feeder conductor ampacity (125% of the largest motor full-load current plus the sum of the rest, NEC 430.24) and the feeder overcurrent-device ceiling (largest branch device plus the sum of the others, rounded down to a standard size, NEC 430.62) for a panel feeding several motors. Full-load currents are the NEC table values; the AHJ governs.
Formula and source
min_feeder_ampacity = 1.25 x largest_FLC + sum_other_FLC (430.24); max_feeder_OCPD = largest_branch_OCPD + sum_other_FLC (430.62), then the next standard size down (it may not exceed the limit).
NEC 2023 (NFPA 70). 430.24 (feeder conductors) and 430.62 (feeder overcurrent protection).
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