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Thursday, March 15, 2018
Question:
Charlie, we are having a disagreement at work about the what size breakers can be used for 14, 12, and 10 gage wire. Some are saying the highest they can be is 15, 20, and 30 amperes. I think there are cases where the breakers can be higher than that. Can you help?
Thanks in advance for your help. We really like CQD. Brooke
A
Answer:
Hey Brooke thanks for your question and we are happy you enjoy CQD.
Small conductors have overcurrent protection rules in 240.4(D) that limits the protection to 15 amperes for 14 AWG, 20 amperes for 12 AWG, and 30 amperes for 10 AWG. The wording in that section allows using higher rated overcurrent devices if specifically permitted in 240.4(E) or (G). You are correct in certain cases the overcurrent devices can be higher such as in motor circuits for example.