A 120/240V single-phase service to a two-family dwelling is provided with a 200A main disconnect. What is the minimum required overcurrent protection for the 120V branch circuits?
- A100A
- 125A
- C150A
- D175A
Exam tip
Always calculate the minimum required protection based on the service rating.
Why B is correct
According to 2024 IRC 210.8(A), the branch circuit overcurrent protection must not be less than 125% of the service rating. For a 200A service, the minimum required protection is 125A (200A x 1.25). Option A is incorrect as it is below the required 125%. Options C and D are also incorrect as they exceed the minimum requirement.