When to use this: when sizing the branch-circuit conductors, OCPD, and disconnect for a single continuous-duty motor. Pair with the NEC Wire Size Calculator for the actual conductor pick from the 125% ampacity, and the Voltage Drop Calculator for long runs.
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.
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.
