Construction
Breaker Size Calculator
NEC requires 125% sizing for continuous loads (3+ hours). Get the breaker right or trip nuisance trips forever.
Breaker size
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- Sized to
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- Std sizes
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- Wire size min
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FAQ
Why 125%? +
Breakers heat up over time at sustained loads. The 125% buffer prevents nuisance trips and stays under the 80% rule.
Examples of continuous loads? +
EV chargers, HVAC compressors, lighting circuits >3hrs/day, refrigeration. Most outlet circuits are NOT continuous.