Code Quiz: Circuit Breaker Requirements in the NEC

Circuit breakers operating at over 1kV, equipped with stored energy mechanisms, shall be designed to prevent the ________ of the stored energy unless the mechanism has been ______ charged.

A) build-up / electrically
B) release / fully
C) potential / manually
D) discharge / partially

See the answer below.

Answer: B

Section 490 of the 2017 NEC focuses on circuit breakers over 1,000V, nominal.

As specifically outlined in 490.45(A), “Circuit breakers equipped with stored energy mechanisms shall be designed to prevent the release of the stored energy unless the mechanism has been fully charged.”

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 [email protected].