Circuit Breaker Sizing

Size a circuit breaker for a load per NEC 240.4. Continuous loads are sized at 125% per NEC 210.20.

Load current (A)

Steady-state load in amperes

Breaker type

General purpose breaker

Continuous load (3+ hours)

Breaker sized at 100% of load

Breaker Size20A

Next standard size above load

Minimum Wire Gauge

14 AWG

NEC Table 310.16 (copper, 75 deg C)

Reference: NEC 240.4 (overcurrent protection) • NEC 210.20 (continuous loads at 125%) • NEC 210.12 (AFCI) • NEC 210.8 (GFCI)

Put your calculations to work.