About 220 Volt Outlets - Modernize 220-volt outlets are the most powerful plugs that you'll find in most residential homes around the United States.These plugs are meant for ovens,dryers and other high-powered appliances that you simply can't power with a standard 110V outlet. While most NEMA outlets transfer 110 volts, larger appliances like dryers, stoves, and air conditioners require more power and use a two-phase 220-volt outlet or three-phase 200-volt outlet. This is a 220v 20 amp outlet as shown in the how-to 220-volt outlet video likely to be used for larger power tools in your garage or shop or perhaps a wall air conditioner.220 volts 30 amps Wire Connections for X Y W 240 Volt Receptacle Dryer Outlets The Black Wire attaches to Outlet Terminal .