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GeneratorCalc
Simple calculators for backup power & energy use
Quick summary
This breaker load calculator estimates how much of a circuit’s capacity your generator-backed loads are using.
Enter breaker amps, voltage, and total running watts to see percent of breaker rating and the 80% guideline.
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GeneratorCalc
Simple calculators & guides for backup power
Breaker load calculator for generator circuits
Use this calculator to see how heavily a breaker is loaded when you run generator-powered circuits.
It uses the basic relationship P = V × I and the common rule of thumb that continuous loads stay at or below about 80% of breaker rating.
Breaker load estimate
Check breaker watt capacity, load percentage, and how that compares to the 80% guideline.
For more planning tools, you can also use the other calculators and guides on the
GeneratorCalc home page.
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