Appliances rated for 250 volts, often referred to 240 volts, each have a specific outlet or receptacle. The air conditioner outlet is a single outlet that provides high voltage power (250 volts) to the air conditioner. Unlike a regular outlet that provides 125 volts to common household loads like lamps, vacuums, and TV’s, the 250-volt air conditioner outlet provides high voltage power via two hot feeds.
Nonmetallic sheathed cable (NM Cable) is used to supply power to the outlet. The outlet requires two hot feeds and a ground wire. In order to achieve this with a standard piece of NM cable, you will use the black and white wires for the hot connection and the bare wire for the ground. The white wire should be marked with a black or red piece of tape to identify it as a hot wire. The ground wire should hook to the outlet as well as the metal box. Simply pigtail a wire for each off of the ground wire and attach.