220 Wiring From House to Garage

Subpanel Circuit

• A 220-volt subpanel circuit consists of a single, double-pole circuit breaker in the main service panel and wires sized to carry the maximum amount of current the circuit breaker allows. The wires connect to the circuit breaker in the main panel and to the line terminals in the subpanel. The main circuit breaker and wires are sized according to the current requirements of the circuits in the garage. The equipment used in the garage determines the current requirements.

220-Volt Wiring

• Two wires each carry 110 volts of current. Used together, they carry a total of 220 volts. One hot wire together with a neutral wire supplies 110 volts. Some large appliances and certain shop tools with electronic controls require both 110 volts and 220 volts. When both voltages are required, two hot wires plus a neutral wire supply them. No neutral wire is needed when only 220 volts are required. A correctly wired 220-volt subpanel in a garage will supply all three types of circuits.

220-Volt Subpanels

• The two wires that connect to the circuit breaker in the main panel carry 220 volts of current to the subpanel. Branch circuits connected to the subpanel supply 110 volts if they connect to a single-pole breaker, or 220 volts if they connect to a double-pole breaker, which uses the two wires that supply the subpanel to provide a 220-volt circuit. The neutral wires for 110-volt branch circuits carry the current back to the subpanel, and the subpanel's neutral wire carries the current back to the main circuit panel.

Ground Wiring

• Electrical codes require all new circuits to have a grounding conductor, or a ground wire. The grounding conductor carries stray electrical current, such as from a short, back to the main circuit breaker panel where it is diverted into the earth. In the main electrical panel, the ground wire or conductor connects directly to the neutral wire. This connection is allowed only in the main circuit breaker panel, not in a subpanel.