FA173884
20 April 2022
Issue:How to calculate the heat generated by a molded case circuit breaker. Watt loss per pole.
Product Line:Circuit Breakers
Resolution:The amount of heat a circuit breaker generates per pole (watts loss) can be calculated with the following formula: P=I^2 x R
- P = Watts loss per pole, in watts
- I = current in amperes
- R = pole resistance in ohms
The pole resistance (in microohms) for most circuit breakers can be found in the Field Testing and Maintenance Guide
0600IB1201.Example: The pole resistance for a Powerpact H frame 15 amp breaker is 35,000 microohms. Convert that to .035 ohms.
Now using P=I^2 x R, P = (15 amps) x (15 amps) x (.035 ohms) = 7.9 watts per pole
