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 branch OCPD on any motor (A) 70
You get
- Min feeder ampacity (430.24) 61
- Max feeder OCPD (430.62) 96 A ceiling
- Standard OCPD (round down) 90
Checked against published worked examples from: EC&M (Mike Holt).
Details, formula, and sources
ScopeThe 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 or tablemin_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).
Source and editionNEC 2023 (NFPA 70). 430.24 (feeder conductors) and 430.62 (feeder overcurrent protection).
Free accessFree read-only access at nfpa.org/freeaccess.
What governsEstimate. AHJ and licensed electrician govern. Verify against the NEC edition adopted in your jurisdiction.
API field nameslargest_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