Electricity is supplied to a home via a circuit box, which takes the electrical feed from outside the home and moderates it for consumption by appliances. A home is divided into various circuits, which in turn power the outlets that appliances are plugged into.
Multiple appliances such as a light, a television and a home entertainment center may share one circuit. Other appliances require a dedicated circuit that only they have access to.
The National Electrical Code, or NEC, is the standard by which all electrical wiring is installed and certified as proper in the United States. If wiring is outside the standards set by the NEC, the building inspector will refuse to approve the final checkoff.
The NEC changes every few years, so it is important to keep the current copy on hand during any electrical work.
By NEC code, fixed appliances such as electric stoves, water heaters and clothes dryers must have a dedicated circuit. These are all extensive users of electricity and can easily trip or cause a fault in a circuit if they are paired with another appliance that needs power.
These dedicated circuits are 240 volts, which is double the normal circuit of 120 volts. The code also requires that each be located within 6 feet of the outlet.
Clothes washers are recommended by the code to be on a dedicated circuit but are not required to be so. Often a gas-powered dryer is hooked up to the same receptacle that is acceptable to the code.
A gas-powered dryer uses such a small amount of electricity that it doesn't affect the washing machine. Any 120-volt electrical receptacles installed after 2008 that are within 6 feet of a utility sink are required to be a Ground Fault Circuit Interrupter receptacle.