A 200A feeder is supplying a new residential building. Which type of overcurrent protection device is required at the main service panel, according to 2026 NEC 240.21(A)?
- ASingle-pole circuit breaker
- Double-pole circuit breaker
- CGround-fault circuit interrupter (GFCI)
- DArc-fault circuit interrupter (AFCI)
Exam tip
Always check for the specific requirements for feeders to dwelling units, as they can differ from general requirements.
Why B is correct
According to 2026 NEC 240.21(A), a double-pole circuit breaker is required for feeders to a dwelling unit to prevent the possibility of a fire from spreading between the phases of a 240-volt, 3-wire, single-phase service. Single-pole circuit breakers are not sufficient for this purpose.