What is the maximum size circuit breaker permitted for a 10 AWG copper conductor with a corrected ampacity of 12.86 amps?

The maximum size circuit breaker permitted for a 10 AWG copper conductor is primarily determined by the corrected ampacity of the conductor and the requirements outlined in the National Electrical Code (NEC). In this case, the corrected ampacity of the 10 AWG copper conductor is 12.86 amps.

When selecting a circuit breaker, it is necessary to ensure that the breaker does not exceed 125% of the conductor's ampacity under the NEC guidelines. The calculation for the maximum allowable breaker size would be as follows:

1. Calculate 125% of the corrected ampacity:

12.86 amps x 1.25 = 16.075 amps.

Since circuit breakers come in standard sizes, you would choose the next highest standard breaker size that does not exceed this calculated maximum. The standard circuit breaker sizes are typically 15 amps, 20 amps, and 25 amps. Among these options, a 15-amp circuit breaker is the correct choice because it is the highest standard size that is still below or equal to the 16.075 amps limit determined by applying the 125% rule.

Thus, a 15-amp breaker is suitable for the 10 AWG copper conductor with a corrected ampacity of