Circuit Breaker Size
Choose a standard circuit breaker rating for a load in watts, with the 125% continuous-load rule, free online.
About this calculator
Load current I = P ÷ (V × power factor) for AC (÷ √3 for three-phase). For continuous loads the breaker should be at least 125% of the load current. The result is rounded up to the next standard rating. Always check the wire ampacity matches.