Standard Light Switch Wiring

Switches open and close electrical circuits, allowing power to flow through lights and appliances. At one time, they were pretty simple—just a toggle you flipped on and off. But things have changed.

©Don Vandervort, HomeTips

Standard Light Switch Diagram

Switches should match the amperage and voltage ratings for the electrical circuit they serve. If your home has aluminum wiring, be sure the switches attached to that wiring are designated “CU-AL” for compatibility—otherwise, they can present a fire hazard.

©Don Vandervort, HomeTips

Single-pole Switch Wiring Diagram

The simplest and most common light switch is actually referred to by hardware dealers and electricians as a “single-pole light switch.” With a single-pole light switch, flipping the lever up completes the circuit, turning lights or appliances on, and flipping it down breaks the circuit, turning lights or receptacles off.

A single-pole switch has two brass terminal screws on the side that receive the black and white wires of the circuit. (The number of terminal screws identifies the type of switch.) Modern single-pole switches also have a green grounding screw (not shown) that connects to the circuit’s ground wire.

The type of switch that will operate hallway lights from either end of the hallway is called a three-way switch; it has an extra terminal.

©Don Vandervort, HomeTips

3-Way Light Switch Wiring Diagram


Light Switches & Controls

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  • Larry

    I have a lighted wall switch. Hooked up a fan and it didn’t work from the switch and I have everything right at the fan. When I looked at the switch I noticed the light was out so I changed the switch and it still out.

    • Don Vandervort, HomeTips

      A basic on/off fan should be wired just like a light. So, considering that you’ve replaced the switch with a new one, unless there are some loose wires or the circuit breaker is off, the problem is probably at the fan. You’re going to have to troubleshoot the electrical circuit.

  • eric sendling

    I want to add a porch light. Can i take power from an exciting switch and jump power to my new switch for light

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