# Light switches in "L"-shaped hallway

My "L"-shaped hallway has a light switch at the end of each leg, a switch at the intersection of the legs and a ceiling-light the middle of each leg.
Originally, the ceiling-lights could be turned on/off from each switch.
I've replaced the original switches with new switches but now only one switch operates the ceiling-lights.
Should a three-way switch be installed at each end of the hallway and the four-way switch be installed at the intersection of the legs? If the answer is "NO", where should the various switches be installed?
How to I determine what wire gets connected to each terminal of each switch?
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You should have replaced the switches with like switches. yes, you'll have 2-three ways and one 4-way. WHERE the 4-way is , is anybodys guess. It's the one with 4 wires on it.
s

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HI "S. Barker",
When you say "...WHERE the 4-way is is anybody's guess..." are you saying it doesn't matter if the 4-way switch is installed at either end of the hallway or at the intersection of the legs?
Gary
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Physically, the 4 way could go anywhere. Electrically, it's located between two 3 way switches. When you install a pair of 3 way switches, Three wires are run between them, two of those wires are called travelers, and get connected to the 3 way switches on the terminals other than the common terminal. When you install one or a hundred 4 way switches into the circuit, they simply go between the travelers, so you're cutting the travelers giving you 4 wires, two from one side go to the input and two from the other side go to the output

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In addition to what S. Barker said: Assuming you noted the "common" terminal on each three way and transferred the wires to the new switches correctly, your problem is likely at the 4 way. The in and out terminals won't necessarily be located in the same position from switch to switch. You'll have 4 wires on that switch. Each pair of wires will come from different cables. One set goes to the input and one set to the output which will be marked on the back of the switch, maybe!!

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I was thinking about how a 4-way is wired. You wire it in pairs so, even though 4-way has 4 wires and 4 screws, you still have a 50-50 chance to wire it correctly.
With a 3-way, on the other hand, you only have a 1 in 3 chance of getting them right.
Also, if you screw up the 4-way nothing will work. If you get it right, then one of the 3 ways will work.
So the OP must have had the 4-way correct.
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One position of a 4way feeds straight through II , The second position feeds through in an X pattern. If you wired it wrong, you'd still make a circuit in the X pattern, so depending upon your 3 way positions you could still get a light
wrote:

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gary wrote:

Gary --
This is not meant as a slam, but you should not embark upon a project like this witout some note paper, sme white adhesive tape, some black eletrical tape, and a small digital camera.
Three ways and 4 ways get complicated because of the way the hots and neutrals " travel", I think is the term.
Let me offer some ideas that could help you, or others, with simlar projects. These are slow and clunky methods, which no licensed professonal electician would use, but these ideas, which I adopted after screwing up several repair jobs back in the distant past, have saved me from similar errors.
AFTER YOU KILL THE BREAKER and unscrew the wall plate, you unscrew the swtch from the box and slowly and carefully pull the switch out of the box. Pull it far enough so that the wires are all extended as far as possibleout of the box.
DONT UNSCREW ANY OF THE WIRES FROM THE TERMINALS ON THE SWITCH YET.
Now, with the digital, photograph every aspect of th connections. You want to see wire colors and screw terminal colors.
Then take the white adhesive tape and start making labels from strips of tape. Label each wire with the wire color and the screw terminal color from the switch. Also label each scew erminal with a label showing the color of he wire attached t it.
Now unscrew the wires from the terminals, and wrap each wire end with electical tape.
Go to your electrical supplier - opefull a real supplier, not the BORG orLOEWS and get a replacement switch.
Install the replacment. You have photos of the original installation; notes and wire labels. Installation should be relatively easy.
This isn't rocket surgery or brain science, but it can be omplicated for a beginner. Thats why going slow, photographing and taking notes, and labeling wires and terminals with 3 ways and 4 ways can help so much.
A licensed electician would do it by training, memory and just looking at the wires. And charge you accordingly and appropriately for that training and memory.
I'm not that good, so I photo and label before disassembling any 3 way or 4 way. With the three ways, I've done enough over the last 40 or so years that I can sort of just "eyeball" it by looking at the terminal screw colors and wire color, but I get lost with the 4 ways.
Hmmm...just thiking that what we commonly call a "three way" is really a two way switch (on off) with three wires and what we commonly call a "4 way" is still a two way (on - off) with 4 wires.
I can't begin to advise you on how to re fix what you already disassembled. You have to be there and looking at it to fix it, becauseofthe issues regarding terminal screw olors and wire colors.

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Hi Jim,
All of your comments are excellent and I know that I SHOULD have done what you've said. But, I didn't.
Given my current situation, I'm looking for help on how to "start from scratch".
Gary
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gary wrote:

I know Gary. And I can't help you there. I would if I could.
I was just trying to let others know how to possibly avoid the poblem, and wasn't meaning to slam you.
I've been in just the place you are in now, and fixing it wasn't fun. It took me a couple days, some wiring books from the local library, lots of paper to diagram out what I was doing, and a lot of tripping of the breaker.
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Hi Jim,
I didn't take your comments as a "slam". A "good kick in the pants" was what I needed BEFORE I started mucking with the switches.
Gary
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First, go to the 4 way location. You have 4 wires that were on the switch. Temporarily splice them together white to white, red to red, or whatever colors you have. Next remove the three wires from each 3 way switch and separate them. Next turn on electricity and check the three wires at each 3 way location. Only one wire will be hot. That wire goes to the common terminal of the 3 way switch. Now connect the two other wires of that switch to the other two terminals. Turn on and off the electric as necessary to be safe. Now go to the second switch location, and with electric on, determine which one of those 3 wires is hot. When located, it gets wired to one of the traveler terminals of the second switch. Now go back to the first switch and flip it once. Now with electric on determine which of the two remaining wires at the second location is hot, and connect it to the other traveler terminal. The final wire goes to the common terminal, and with electric on the light should work properly from both 3 way switches. Last unsplice the 4 wires at the 4 way location and connect one set to the input and one set to the output of the switch

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My "L"-shaped hallway has a light switch at the end of each leg, a switch at the intersection of the legs and a ceiling-light the middle of each leg.
Originally, the ceiling-lights could be turned on/off from each switch.
I've replaced the original switches with new switches but now only one switch operates the ceiling-lights.
Should a three-way switch be installed at each end of the hallway and the four-way switch be installed at the intersection of the legs? If the answer is "NO", where should the various switches be installed?
How to I determine what wire gets connected to each terminal of each switch?

I guess I'll take this one on since no one else wants it. LOL
Open up all of the switches and leave them hanging out. Don't disconnect anything yet. If what you had before was two 3-way switches and one 4-way switch you should of had two electrical switch boxes with 3 conductors and possibly a ground wire and one electrical switch box with 4 conductors and possibly a ground wire. Hopefully you did not disconnect any other wires in each switch box.
Go to the box with the four conductors and disconnect that switch. Two of the conductors should be in one cable and the other two conductors should be in another cable. Splice the wires from one cable to the wires in the other cable separately. At this point it doesn't matter which goes to where as long as they are spliced to the other cable.
Now see if the 3-way switches work properly. If not then you need to identify the hot wire in one of the 3-way switches. This is the only wire that remains hot regardless of any of the switches position. It would be best to disconnect the wires from one of the 3-way switches at this point. When you find the hot put that wire on the darker colored screw on the 3-way switch and put the other two remaining wires in that box on the other two identical screw terminals on the 3-way switch. Only one switch box will have the hot wire.
Now check to see if the 3-way switches are working properly. If not then you need to identify the load wire in the other 3-way switch box. Disconnect all of the wires from this 3-way switch. Check to see which one is hot. Then go flip the 3-way switch that you previously worked on. Go back and check to see which wire is hot now in the second 3-way switch box. Those two wires will be your travelers and will go onto the 3-way switch screw terminals that are identical. The one wire that was never hot will go on the one screw terminal that is a different color.
Now both 3-way switches should be working properly. Back to the 4-way switch. Unfortunately each switch manufacturer has their own wiring configuration, but usually it is either top and bottom or each side. If you still have the package that the 4-way switch came in there may be a wiring diagram with it or there may be a wiring diagram on the back of the switch. Basically you want to take each pair of wires and either wire them top and bottom or side and side onto the 4-way switch.
I would use a pigtail socket and bulb to test for the hot wires as a multimeter can just add to the confusion. It is easiest to do this while the circuit is hot, however I do not recommend that for a novice. Maybe you can have someone standing by the circuit breakers and give him or her a yell when you want the breaker flipped. Always check the wires to make sure that the other person has actually killed the power before proceeding.
Good luck.
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Or just do one at a time.
If you didn't mark the wires at the switches then this could get interesting.
There is a logical way to continue........
The first thing you need to do is identify the switch the hot comes into. It will be one of the 3-way boxes.
The two 3-way boxes will have 3 wires and the 4-way box will have 4.
Let us know what you have. If you didn't mark anything the next step is to disconnect everything.
On Sat, 26 Jan 2008 10:27:28 -0800, jJim McLaughlin

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gary wrote:

It all depends on how the physical wiring was done originally in your house. There are many possible variations, but they are all "logically" the same
go here for a diagram that may be of help understanding what you are up against, and what you need determine about your specific physical wiring layout.
http://www.thecircuitdetective.com/3and4wyinfo.htm#fourbasic
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Reed wrote:
SNIP HAPPENS

Thank you.
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Great link. I'm going to try studying it to see if I can figure out a problem I am having. In my case, I only have two 3-way switches (no 4-ways). But, I also have knob and tube wiring in my house. I don't know if that will change anything, but I'm going to give it a try.

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On Sat, 26 Jan 2008 09:24:19 -0800 (PST), gary

Turn the power off and disconnect all switches.
Turn the power on and use a tester to find the only wire in the bunch that is hot.
When you find the hot wire, turn the power off and wire the hot wire to the black screw on the 3-way switch and connect the other two wires to the other two terminals. (This switch is done)
Turn the power back on and go to the 4-way. One of these wires should be hot. It will share another wire in the same cable. If you flip the finished 3-way switch the other wire will become hot. Mark these two. Turn the power back off and wire these two to the same color screw terminals on the 4-way switch. Wire the other two wires in the box to the other two screw terminals of the 4-way switch. (This switch is done)
Turn the power back on and test the last box. One wire will be hot. When you flip the switch another wire will go hot. The wire that does not go hot in either position you will tie it to the black terminal on the 3-way switch after you turn the power back off. Then wire the remaining two wires to the other two terminals on the switch. (weekend project done)
Then, next time, mark the wires or take pictures or do them one at a time.
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Terry wrote:

Yeah! What he said!
Good job, Terry!
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That's a great explanation. It makes me want to try it for a similar problem that I have and haven't been able to figure out.
In my case, I only have two 3-way switches to figure out (no 4-ways). But, I have knob and tube wiring in my house instead of more modern two-wire wiring. I'm guessing (hoping) that won't make any difference. I have spent forever trying to figure mine out and basically had given up.

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