National Electrical Installation Standards

Standards as High as Your Own

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Thursday, March 28, 2019

Question:

How many over current devices should two pole circuit breaker considered be ?

Safa Benosh

A

Answer:

Hey Safa thanks for your question. It depends on what rule you are asking about. In general an overcurrent device must be installed in series with each ungrounded conductor as stated in 250.15 and 240.92. For those rules the two pole circuit breaker is considered to be two overcurrent devices, one pole for each ungrounded conductor.

For the purposes of being considered a (single) disconnecting means, a multipole circuit breaker, or even individual single pole circuit breakers with identified handle ties, such as stated in 225.33 and 230.71 is allowed.

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