Feeder for a Group of Motors (NEC 430.24 / 430.62)
Feeder conductor and overcurrent device for several motors on one feeder.
Example
You enter
- Largest motor FLC (A, table value) 28
- Sum of other motor FLCs (A) 26
- Largest motor branch OCPD (A) 70
You get
- Min feeder ampacity (430.24) 61
- Max feeder OCPD (430.62) 96 A ceiling
- Standard OCPD (round down) 90
Details, formula, and sources
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.
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).
Free read-only access at nfpa.org/freeaccess.
Estimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
Field names used by the API: largest_flc_a, sum_other_flc_a, largest_branch_ocpd_a, min_feeder_ampacity_a, max_feeder_ocpd_a, standard_feeder_ocpd_a
- FLC table value each motor full-load current must be the NEC table value (430.248 / 430.250), user-supplied; the tile does not bundle the motor FLC tablesNEC 2023 430.6 / 430.248 / 430.250
- Standard sizes the feeder OCPD is rounded down to a 240.6(A) standard size because 430.62 sets a ceiling that may not be exceededNEC 2023 240.6(A) / 430.62; the AHJ governs