Fill in the blank

What is the interrupting rating of a circuit breaker that has no interrupter rating marked on it? This is in reference to circuit breakers not used for supplementary protection.

  1. 5,000A
  2. 10,000A
  3. 42,000A
  4. 65,000A

Answer: A

As noted in 240.83(C), "Every circuit breaker having an interrupting rating other than 5,000A shall have its interrupting rating shown on the circuit breaker. The interrupting rating shall not be required to be marked on circuit breakers used for supplementary protection." This means that circuit breakers shall have their interrupting rating marked on them if their interrupting rating is other than 5,000A, provided the circuit breakers are not used for supplementary protection.

Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states. He can be reached at necexpert@aol.com.