Which circuit breaker may be used with No. 12 wire?

Using No. 12 wire allows for the safe use of either a 15-ampere or a 20-ampere circuit breaker in a residential or commercial electrical system. This is because No. 12 wire is rated for a maximum current of 20 amperes, making it suitable for both circuit breaker ratings.

When selecting a circuit breaker, it's important to consider the wire gauge and ensure that the breaker does not exceed the wire's capacity to prevent overheating and potential fire hazards. A 15-ampere circuit breaker is common for circuits that power outlets and lighting, while a 20-ampere breaker is often used for circuits that may carry heavier loads, such as kitchen appliances. Therefore, choosing either of these options aligns with the National Electrical Code (NEC) guidelines and provides appropriate protection for the circuit.

In scenarios where only one specific amp rating was provided as an option, it would limit the flexibility of circuit design, as both a 15-ampere and a 20-ampere circuit breaker can be safely used with No. 12 wire.