Replacing Three-way Switches

Replacing Three-Way Switches

If a switch does not have ON and OFF marked on its toggle and has three terminals (not counting the ground), it is a three-way switch. A pair of three-way switches can control the same fixture by flipping the toggle on either switch.

If one or both of a pair of three-way switches fail to control the light, replace the faulty switch or switches. If the toggle is wobbly, replace the switch.

If you keep track of which wire goes where, replacing a three-way switch is not much more difficult than replacing a single-pole switch. If you forget to tag the wires, however, the proper connections can be difficult to figure out.

Checklist

Time
About 25 minutes if you remember to tag the wires; possibly longer if you forget

Tools
Screwdriver, side cutters, voltage tester, strippers, long-nose pliers

Skills
Stripping wires and joining them to terminals

Prep
Lay a towel or small drop cloth on the surface below the switch

Materials
One or two three-way switches, wire and wire nuts for pigtails, electrician's tape

Step 1

Shut off power, remove the cover plate, pull out the switch, and test for power. A three-way switch has a common terminal that's a different color than the two traveler terminals. Tag the wire that connects to the common terminal.

Step 2

Cut and restrip wire ends and form them into loops. Connect the ground wire to the new switch. Connect the tagged wire to the common terminal and the other two wires to the traveler terminals. (It doesn't matter which wire goes to which traveler terminal.)

Replacing a Four-Way Switch

If three or more switches control the same fixture, two are three-way switches and the others are four-way switches. A four-way has four terminals (plus a ground). Two wires connect to input terminals and two to output terminals. Before you remove the switch, tag each wire. Without tags, it could take a pro to sort them out.


Comments (3)
8222209883
kelvin_heggs wrote:

can I see a diagram of a 3-way lighting circuit?

4/5/2011 09:23:02 PM Report Abuse
lawrencerhodes wrote:

I'm replcing a dimmer switch with a new one and there is no ground green wire to connect. Where do I connect the new green ground wire to. Thanks

1/28/2011 02:32:29 PM Report Abuse
chrisnvick wrote:

Is there a way to figure out which is the common wire in a circuit? I was replacing some very old switches and did not realize this until after I had unwired the old switches, now I have to have both switches off to have no power to light or both switches on to power light. Not exactly what I wanted. Can someone help me with locating the common? I have tried some other configurations but there always seems to be some power going to the light as that the cfl flickers and never totally shuts off.

12/31/2010 08:40:00 AM Report Abuse
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