Motor FLA & Branch Circuit Calculator

Looks up motor FLA from NEC Tables 430.247-250 by horsepower / voltage / phase, then applies the 125% conductor factor (430.22) and the breaker / fuse multipliers from Table 430.52.

Phase

Nominal voltage

Horsepower

OCPD type (Table 430.52)

Results

FLA from NEC Table—

Conductor ampacity required (NEC 430.22, 125% FLA)—

OCPD calculated value (NEC 430.52)—

Recommended OCPD (next standard size up)—

Disconnect rating (115% FLA min, NEC 430.110)—

Last reviewed: April 2026 (NEC 2023). Values are for planning; the NEC tables themselves govern.

Tools we used or recommend for this work: a clamp meter that handles inrush capture (Fluke 376 FC class), a torque screwdriver for breaker terminations to spec, and a Klein insulated nut driver set. Links may be affiliate-tagged where the brand has a program.

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