Motor Circuit Calculator

Motors pull 5 to 7 times their normal current when they first start up, so you cannot size a motor circuit the same way as a regular circuit. NEC Article 430 has its own rules. This tool looks up the motor's full-load amps from the NEC tables, then calculates the minimum wire size and the maximum allowed breaker size.

Tip: Always use the NEC table FLA value, not the motor nameplate FLA, for branch circuit sizing. The nameplate value is used for overload protection only.

Motor Circuit Results

FLA (A)
Min Conductor
Max OCP (A)
Overload (A)
RequirementValueNEC Ref