A circuit breaker with a _____ voltage rating, such as 240V or 480V, can be used where the nominal voltage between any two conductors does not exceed the circuit breaker voltage rating.

• A. Straight
• B. Rounded
• C. Adjusted
• D. Matched

Answer: (A)

The key idea is that a circuit breaker’s voltage rating is the maximum voltage across conductors that it is designed to interrupt safely. You may install a breaker on a circuit as long as the nominal voltage between any two conductors does not exceed that rating. A fixed, specified rating like 240 V or 480 V is described as a straight voltage rating, meaning the rating is a clear, unadjustable value that defines where the breaker can be used. Using a breaker with a rating at or above the system voltage ensures the insulation and interruption capability are appropriate. The other descriptors don’t correspond to how breaker voltage ratings are defined or applied.