What size wire do I need for 60 amps?

It's recommended to use a 4-gauge wire for 60-amp appliances like an electric furnace or a large electric heater. While it’s common to use a 6-gauge wire for 60-amp breakers in practice, it’s best to use a 4-gauge wire if you’re installing a 60-amp subpanel. 60-amp breaker panels controlling several circuits can draw a max of 60 amps before the subpanel breaker trips.