Appliances designed for use in America run on 110-volt or 120-volt AC electricity. The exceptions to this are high-energy appliances like washers, dryers, refrigerators and HVAC units. However, most of the rest of the world runs on 220-volt or 240-volt circuits. International travelers need to purchase adapters to avoid damage.
In America, the household voltage runs between 110 and 120 volts. Heavy-duty appliances are placed on their own circuit because of the extra voltage required to operate them. Many of these appliances operate on 220 or 240-volt circuits, and are marked as such on a circuit breaker panel and have thicker wires designed to carry more current. They also have three-prong grounded plugs that can withstand a power surge, whereas older 110-volt outlets may only have the two-prong sockets. Newer 110-volt plugs have a ground wire included.
Electrical appliances typically have the voltage and other electrical requirements typically listed somewhere on the label, if it has been purchased from another part of the world that uses different voltage. Users should consult this first before plugging it into a wall outlet; a 220-volt device does not work if plugged into an 110-volt outlet, and doing the reverse can cause serious damage or injury.