For circuit breakers installed in equipment operating at over 1,000V, the interrupter rating of a circuit breaker shall not be less than the maximum fault current the circuit breaker will be required to interrupt, including _______ from all connected sources of energy.
A) ratings
B) contributions
C) information
D) none of the above
See the answer below.
Answer: B
Article 490 covers the general requirements for equipment operating at more than 1,000V, nominal. As specifically outlined in Sec. 490.21(A)(4)(2), “The interrupting rating of a circuit breaker shall not be less than the maximum fault current the circuit breaker will be required to interrupt, including contributions from all connected sources of energy.”
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].