What size breaker is required for a 12-gauge copper wire?

When dealing with the appropriate size breaker for a 12-gauge copper wire, it's important to consider the National Electrical Code (NEC) guidelines regarding conductor sizing and breaker sizing. According to these guidelines, a 12-gauge copper wire is rated for a maximum of 20 amps. This rating allows the wire to safely carry the current without overheating or posing a fire risk.

Using a 20-amp breaker ensures that the breaker will trip if the load exceeds the safe carrying capacity of the wire, thus providing adequate protection. A breaker needs to be sized correctly to prevent nuisance tripping while also providing safety; hence the 20-amp breaker is ideal for wiring with a 12-gauge conductor. It effectively balances the amount of current that can be safely handled while also ensuring that if there is a fault (such as a short circuit), the breaker will trip to avoid damage to the wiring and connected devices.

This consideration is crucial in practical applications, to maintain safe electrical systems in residential and commercial wiring. So, for a 12-gauge copper wire, the correct choice of a breaker is a 20-amp breaker.