Which gauge wire is most appropriate for a 15-amp circuit?

For a 15-amp circuit, the most appropriate choice is 14 gauge wire. The National Electrical Code (NEC) recommends using 14-gauge wire for circuits that are protected by a 15-amp circuit breaker or fuse. This is primarily due to the capacity of 14-gauge wire to handle the current without overheating, providing a safe level of operation.

Using 12-gauge wire is generally suitable for 20-amp circuits, which can lead to unnecessary expense and less flexibility in handling loads, while a 10-gauge wire is designed for circuits handling higher current loads (30 amps). Conversely, 16-gauge wire is not adequate for a 15-amp circuit since it falls below the safe capacity needed for that amperage, posing a risk of overheating and potential fire hazards.

Thus, 14-gauge wire strikes the right balance between capacity, safety, and cost for a 15-amp circuit.