What size wire should I use for a 40A0-240V line?
You can run the cabling from your circuit to the breaker box.The gauge is designed to operate with the power rating of your breaker.At least number 14 gauge wire is required for a 15 Amp and a 20 Amp breaker.
Do I need a neutral wire?A 120V load only needs two ungrounded conductors, one from each end of the secondary coil.Some loads need both neutral and ungrounded conductors.
The same 12-gauge wire can be used for a 220v, 20-amp outlet to run power tools.The cable must have a hot wire.You need a different type of receptacle and 10-gauge cable if the appliance draws 30 Amps.
There is a simple way to get a 240-volt circuit.A double-pole circuit breaker is clipped into both 120 buses at the same time, so the voltage to the circuit is doubled.Two hot wires and a neutral are needed to carry the electricity to the appliance.