Originally Posted by ERASER5 (Post 7092458)

If the white wire exits, then in the future, you can split the 220V into two 110v circuits without having to pull new wire.

For now, cap the white wire with a wirenut and fold it into the back of the box. A future owner will thank you.

Originally Posted by truckster (Post 7092236)

They're totally different. Think of it this way: the electrical service brought into your house is 220 volts single phase. In your breaker box, you have two strips of breakers; each one is for one "side" of the phase. In other words, the two phases are 180 degrees out of sync. When you wire a 110v circuit, it's connected to one of the phases on the hot side (black wire) and goes to ground through the neutral (white) wire, which completes the circuit. The bare copper wire is a ground, which is there for safety's sake.

When you connect both phases (really, both sides of one sine wave), you end up with 220v; one phase is represented by the black wire and the other by the red wire. Since the circuit is completed by the two hot wires, you don't need a neutral. Again, the ground is there as a safety measure. So a 220v outlet is different from a 110v outlet, and you should never (NEVER!) substitute one for the other.


To make things a little more confusing, some 220v outlets (such as for electric clothes dryers or stoves) DO have a neutral leg, and as a result will have a 4-prong cord instead of a 3-prong cord. That's because those appliances use both 220v (for the burners, for example) and 110v (for the clock). The older electrical code allowed for the use of the ground wire in that type of circuit to complete the 110v leg, but current code requires a separate neutral wire. It is permissible, however, if you have a newer appliance and an older outlet to use a 4-prong to 3-prong pigtail

I hope this helps.