FIG. 00 — IN PROGRESS
CIRCUIT BREAKER SIZE CALCULATOR
Determine the correct overcurrent protection device size (circuit breaker or fuse) for a given continuous or non-continuous load per NEC 240.4 and NEC 215.3.
⚠ STATUS · TOOL UNDER FINAL VALIDATION
We're finalizing this calculator's NEC validation. In the meantime, use the conduit fill calculator and the wire fill chart on the homepage.
FIG. 01
WHAT THIS TOOL WILL CALCULATE
- 01Input: load current in amps, load type (continuous, non-continuous, motor, motor-operated appliance)
- 02Output: minimum breaker size, recommended breaker size (next standard size up), required wire gauge cross-reference
- 03Applies NEC 215.3 (125% rule for continuous loads), NEC 240.4(D) small-conductor rule, NEC 430.52 (motor branch protection)
- 04Cross-references the wire ampacity calculator and conduit fill calculator for matching conductor size