How to Wire a 20A 240V Double Pole Switch | Hunker Wiring a 20-amp, 240-volt switch can be a confusing experience for the average homeowner used to working with standard 110-volt circuits. For one thing, both supply wires for this switch carry voltage. This switch doesn't use a neutral conductor. With both conductors carrying 120-volts, there is an increased risk of injury or property damage. Rocker Switch Wiring Diagrams | New Wire Marine This is a Double Pole Double Throw DPDT, momentary illuminated momentary rocker switch It has one ind lamp at the top. The wiring diagram to the right will show how to wire and power this 12V 20AMP (ON)-OFF-(ON) 3 way Carling Contura rocker switch.