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 3 Wire 220 Volt Wiring Diagram | Wirings Diagram Dec 10, 20183 Wire 220 Volt Wiring Diagram – 3 wire 220 volt wiring diagram, 3 wire 220 volt wiring schematic, 3 wire 240 volt wiring diagram, Every electrical structure consists of various diverse components. Each part ought to be set and linked to different parts in specific manner. If not, the arrangement will not work as it ought to be.