What size wire is typically used for a 30-amp circuit?

For a 30-amp circuit, the appropriate wire size is 10-gauge wire. This size is standard for electrical installations involving a 30-amp breaker, as it provides the necessary amperage carrying capacity while also taking into account safety and potential voltage drop over distance.

Using larger gauge wire, such as 8-gauge, while safe, is generally unnecessary for a 30-amp circuit unless specific conditions require it, such as longer runs where voltage drop needs to be minimized significantly. Meanwhile, using a smaller gauge like 12-gauge or 14-gauge would not be adequate, as they are rated for lower amperages (20 amps and 15 amps, respectively) and could overheat or present a fire hazard if subjected to a 30-amp load.

Thus, 10-gauge wire is the most suitable and commonly accepted choice for ensuring safe operation for a 30-amp circuit while adhering to National Electrical Code (NEC) guidelines.