Wiring Diagrams for Electrical Receptacle Outlets - Do-it Wiring a 20-Amp 240-Volt Appliance Receptacle. This outlet is commonly used for a heavy load such as a large air conditioner. The outlet should be wired to a dedicated 20-amp/240-volt circuit breaker in the service panel using 12|2 awg cable. With this wiring, both the black and white wires are used to carry 120 volts each and the white wire is wrapped with electrical tape to label it hot. Help with wiring a 240 Volt receptacle | The Home Depot Am wiring a 240v dedicated receptacle. Line coming into receptacle is (black, white, ground). Plug coming from the dedicated table saw is (black, white, red, green/ground). The saw is 240v 5hp. So my question is what do I do with the red wire coming from the saw, since at the wall there is no red wire.