Wiring 3 and 4 Way Switches
Summary: A 3 way switch and 4 way electrical switch can be confusing to understand. A 3 way electrical switch installation is done to control a light from two different places. A 4 way switch is used with a 3 way switch for three or more control spots. The placement of both is important. This video will help you with your 3 way switch wiring.
Related Articles: wiring diagram, 3 way & 4 way switches, fixing wiring problems
DEAR TIM: I have two interior hallway lights that are controlled by 3 separate electrical switches. My husband tried to install new decorative switches and now the lights come on only part of the time. What in the world do you think he did wrong? I need an aspirin! R.L.
DEAR R. L.: In all fairness, he may have done nothing wrong. You possibly have a defective switch. However, the smart money is on your husband. Sounds like another weekend warrior who was not prepared for battle.
Your problem is a fairly common one. It involves what are known as 3 way and 4 way electrical switches. These simple devices create more problems than they deserve. Your headache will vanish with a little effort on your part. Let's take a quick electrical switch 101 course.
The placement of the switches is critical. The 4 way switches must be in between the 3 way switches. In other words, the power from your circuit panel must first enter the 3 way switch before it goes to the 4 way switch. From that 4 way switch it then travels to an additional 4 way switch or, in your case, to the final 3 way switch. The path that the electricity follows as it passes between the switches is not unlike a railroad switching yard.
Three way and 4 way switches are easy to distinguish. A 3 way switch has 3 terminals (not counting the green grounding terminal) or locations where wires attach. A 4 way switch will have 4 terminals. In almost all instances the 3 way switches will have one of the three screws painted or tinted a dark color or black. This is important! The 4 way screws are almost always a standard brass in color.
Since the switches worked before your husband fiddled with them, we know that the original electrician did his job correctly. We need to start this project by killing the power to the circuit. Turn off the circuit breaker in the panel that controls the hall lights. Check to make sure the power is off.
Take the cover plates off all three switches. Remove the switches from the electrical boxes. Do NOT remove any wires from the switches at this point. First of all, do you have two 3 way switches and one 4 way switch? Are there any single wires in a box that are not attached to anything? Good! This will be easy.
The problem is very likely at one of the 3 way switches. A traveler wire, one that should run between the 3 way and 4 way switch is probably on the dark colored terminal. The dark colored terminals are reserved for just two wires. The common or continuously hot wire from the electrical panel should connect to one of the dark terminals on one of the 3 way switches. The other dark terminal on the remaining 3 way switch needs to connect to the common wire that travels to the first light fixture. Trace these wires using a continuity tester and throw away the aspirin.
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Comments:
roland spengler 03 Feb 2008, 10:43
this page did not tell me squat about wiring a 4-way swithch; it's a waste
of time
AsktheBuilder 03 Feb 2008, 11:32
Roland,
Some people make it so hard to love them...... Did you read the pop up window *before* you typed your comment? If you did, you would have found this column in about five seconds: http://www.askthebuilder.com/707_4_Way_Switch.shtml You may want to cut back on your consumption of Grumble Soup. It doesn't agree with you. :->
tim gerard 23 Feb 2008, 17:58
Thanks so much. Read the text once and then watched the video. I wired the
circuits the first time correctly. Awesome info!
william 26 Feb 2008, 08:00
I have the power wire coming into the light and one 3 ways switch on one
side of the room wire going to the light and the other 3 way switch on the
other side of the room and a wire going to the light. How do I wire this
up. Please help. Thanks
Glenn 27 Feb 2008, 19:49
I have a single box (#1)fed from the panel with 12/2
there is a 12/3 wire feeding into box (#2) a duplex box a 12/2 wire feeds the lights ( good so far) the duplex box has a second 12/3 exiting from the duplex box and feeding into another single box. A 12/ wire feeds a second set of lights. how do I fed the second S3 in the duplex box from the other S3 so that the second set of lights are not controlled by the two S3's? Thanks, Glenn
E2 28 Feb 2008, 20:55
this is some tips for Glenn
your question was alittle hard for me to understand but from what i make of it u may wanna try this. if u want a separate "single pole" switch to control the second set of lights, -u would then need to run a 12/2 (if 12 wire is required in the location by code) from either the switch that is feeding the room, or a nearby outlet to the new switch and splicing the wires accordingly to get power for that second set of lights in that switch box -then run another 12/2 to the second set of lights from the new switch. proceed to put wire nuts on the old 12/2 that in the past fed the light and rehang the fixture using your newly ran feed for the light
E@ 28 Feb 2008, 20:58
or just call an electrician like myself if u have no electrical background
AsktheBuilder 02 Mar 2008, 09:56
William,
You need to get the power wire to the first 3 Way switch. Then just follow my instructions in the column and the video.
john 25 Mar 2008, 12:05
me i hav a question about wiring diagram 3way and 4 way switch diagram
,,,,,,, i am electrician here in philipines and pls help me to learn more
about electrical works.im waiting ur responds thank you and god bls you.
john from philipines.
AsktheBuilder 25 Mar 2008, 12:12
John,
Just go read all of my Electrical columns and watch my videos. That should give you a good start. View all comments |
