Standard household electric power in the United States is 110 to 120 volts, with a 60-cycle alternating current, and most household washers can be plugged into wall outlets supplying this current. But washing-machine users risk dangerous electric shock if they plug their washers into an outlet that lacks adequate electrical safeguards.
Washing machines can be plugged into a standard three-wire grounded AC circuit that is equipped with circuit-breaker protection. The breaker cuts off current if there is a short or overload on the electrical circuit supplying power. The washer's circuit and its breaker must be able to handle at least 20 amps. The washer should be the only electrical device on the circuit, and the electric outlet should be a grounded three-prong.
Installing a ground fault interrupting (GFI) outlet provides an extra level of protection against electric shock, but a GFI outlet is not required for washing machines under the National Electrical Code unless the washer outlet is located in an unfinished basement or within 6 feet of a sink. The GFI outlet instantly cuts off electricity to the washer if it detects faulty grounding in the washer or on the washer circuit. A washer may run with faulty grounding but the machine could deliver a strong or lethal shock to users.