Electrical Tools

Breaker Size Calculator

Calculate the correct circuit breaker amp rating for motors, HVAC, appliances, and general electrical loads. NEC compliant breaker sizing.

Load Specifications

Breaker Sizing

Breaker Size 0 amp
Min Wire Size - AWG
Calculated Load 0 amps
Safety Factor 125%
Breaker Type Standard
Max Load Continuous 0 amps
Wire Ampacity 0 amps
Est. Breaker Cost $0

NEC Sizing Rules

  • General: 125% of continuous load
  • Motors: 250% FLA max
  • AC Units: Per MCA on nameplate
  • Heat: 125% of total load

Formula

Continuous Load: Amps × 1.25

Breaker Size: Next standard size up

Wire Size: Match breaker ampacity

Max Continuous: Breaker × 0.8

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