The wire size for a given circuit is determined by the current draw of the circuit and the length of the wire run. The current draw of a circuit is measured in amps, and the wire size is measured in AWG (American Wire Gauge). The lower the AWG number, the larger the wire.
For a circuit with an 80 amp breaker, you will need to use 6 AWG wire. This is because 6 AWG wire is rated for a maximum current draw of 95 amps, which is more than the 80 amps that the breaker will draw.
The length of the wire run also affects the wire size that you need to use. The longer the wire run, the larger the wire size that you will need to use. This is because the longer the wire run, the more resistance there will be in the wire, and the more voltage will be dropped over the wire.
For a circuit with an 80 amp breaker and a wire run of less than 100 feet, you can use 6 AWG wire. For a circuit with an 80 amp breaker and a wire run of more than 100 feet, you should use 4 AWG wire.
