How to wire a three-way light switch

Sometimes it is necessary to control a light from two different places; for example, the top and bottom of a stairway. When wired correctly, the light can be turned on or off from either switch. This can be done with two (2) three-way switches. To control a light from more than two switches, use four-way switches. There are several ways to wire three-way switches to a fixture. This is the simplest way.

Instructions

1. • 1

     Between the fixture and the first switch, run two-wire cable. Then, between the two switches, run three-wire cable.

   • 2

     The feed wire (from the power source) should be two-wire and will have a black wire and a white wire. Using a wire nut, attach the white wire from the feed to the white wire at the fixture.

   • 3

     The black wire from the feed will run straight through the fixture to the two-wire cable running between the fixture and the first switch. Using a wire nut, attach the black wire from the feed to the white wire of the two-wire cable running between the fixture and the first switch.

   • 4

     Using a wire nut, attach the black wire from the fixture to the black wire of the two-wire cable running between the fixture and the first switch.

   • 5

     Go to the first switch. The white wire coming from the fixture should be attached to the dark colored screw on the switch. It is a good idea to mark this screw with paint or a permanent marker to indicate that it is “hot”.

   • 6

     Take the red and white wires from the three-wire cable running between the two switches and attach them to the light colored screws on the first switch.

   • 7

     Attach the black wire coming from the fixture directly to the black wire running between the two switches with a wire nut. The black wire should not be attached to the first switch.

   • 8

     Go to the second switch. Attach the red and white wires to the light colored screws and the black wire to the dark screw.

   • 9

     Test your switches. You should be able to turn the fixture on or off from either switch.

Tips & Warnings

• When stripping your wires, only strip the amount you need. Be sure you do not have bare wires touching each other. This can cause a short, which can result in a tripped breaker, blown fuse, or (worst case scenario) fire.

• Always tape connections made with wire nuts to avoid bare wires contacting other bare wires.

• BE SURE TO CUT THE POWER TO THE AREA BY TRIPPING THE BREAKER OR

• PULLING THE FUSE BEFORE WORKING.

• Always replace switch covers to avoid the risk of electric shock.