10-gauge wire is usually used for short 30 amp runs. If you plan on going over 150 feet, 8-gauge wire or thicker will be needed.

What wire do you use for 30 amps?

10-gauge wire “Twelve-gauge wire is good for 20 amps, 10-gauge wire is good for 30 amps, 8-gauge is good for 40 amps, and 6-gauge is good for 55 amps,” and “The circuit breaker or fuse is always sized to protect the conductor [wire].”

What wire do I use for RV service?

You should use the No. 4 AWG size for a 50 amp wire. This is the best size wire for 50 amp Rv service. Whether you have a 30 amp, 40 amp or a 50 amp breaker, wire size is essential.