3-Way Switch Problem

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  #1  
Old 07-12-07, 08:54 PM
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Question 3-Way Switch Problem

I am replacing both 3-way switches that control a light in my hallway. Upon checking the feeds, I found that both switch contain 14-2 wires. Each switch has three black, two white and grounds. There is a hot wire coming into each box as well. I have looked up three switches and cannot find instances where the hot is coming into both switches. I'm not sure how to deal with the hot from the second switch. How can I hook this up correctly?

Also, I removed the old switches and noted the switch placement on the old switch. When I hooked it up using that configuration, the switches wouldn't work correctly. Only one of the switches (switch 1)would turn the light on initially, the other switch (switch 2) would then be able to toggle the lights off and on. If switch 1 was off, switch 2 did nothing.
 
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  #2  
Old 07-12-07, 10:21 PM
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How did you determine that you have a hot wire in both switch locations? Are there any other switches located in the same boxes as the switches in question?

Either way, had you replaced the three-way switches wired the same way, it would have worked if it worked before.

Did you go by the locations of the wires on the switches or by the colors of the screws on the switches when you replaced them? Many models have the screws in different places, so you have to pay attention to which screw is for the common (which does not mean white or neutral in this case.)
 
  #3  
Old 07-13-07, 05:19 AM
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I suspect that you did not wire the switches the same way as before. If you made connections based on terminal position (top left, bottom right, etc.) then you may not be correct. With three way switches you MUST make connections based on terminal color. There are two traveler connections (the same color screw) and one common connection (odd color screw). On newer three way switches there is also a ground connection.

I also suspect that you method for determining two hot wires is flawed.

Either way, there are a limited number of ways to connect wires to three way switches (6 per switch) and only half of them are electrically different. This means that by trial and error you can figure it out fairly quickly.
 
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Old 07-13-07, 05:44 AM
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The switches I took off didn't have any difference with the terminal color, so I rewired based on location.

To find the hot, I took both switches apart and then turned the power back on and tested each black wire with the neutral to find if there was power or not coming from that wire.
I found that each switch had two hot wires.
Did I use an incorrect method?

Both boxes had just the one switch.
I guess I could just try the different combinations untill one works.
I was just confused about the hot wires.
What else did I do wrong?
Thanks
 
  #5  
Old 07-13-07, 05:54 AM
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Did you have the wires at both switches completely disconnected when you made your tests?

Please describe how 14-2 wires are used, if each switch has 3 black wires, two whites and two grounds. 14-2 (a cable assembly containing one black, one white and one ground) would imply the same number of each wire. Where does the extra black wire come from?

Regardless, if this setup (however incorrect it may be) worked before, then it should work with new switches. The only conclusion is that you did not hook the wires up to the proper terminals.

As for the setup, until I know exactly what you have, I can't comment on how safe or unsafe it is.

What type of boxes are used? How many cables exist? What wires are in those cables? How were those wires connected (before you did anything), to the best of your memory?
 
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Old 07-13-07, 07:04 AM
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If you have the old switches and they are not damaged you can tell which screw is common with a multi tester. One screw will show continuity to both of the other screws depending on switch position. That's the common. Two screws will never show continuity between each other regardless of switch position. They are the travelers. Once you know which is which that may help hooking up the new switch.
 
  #7  
Old 07-13-07, 11:23 AM
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Do you still have the old switches? Can you put them back and make it work properly? If so then do it and then change one switch at a time. The new switch will have the common screw marked. There are only three wires on the old switch and it will take three tries at most to get it to work. It doesn't matter if the traveler wires are reversed. If you get the common wire correct the switches will work.

When you get the first one working then swap out the second one.
 
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Old 07-13-07, 04:34 PM
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Thanks for all of your helpful. It's amazing how easy things are when you just take your time. My impatience doesn't always afford me this luxury.
Just one more question.
So, the switch is working fine.
However, I did have one question. Its seems that instead of using 14-3 wire, the extra black wire in the switch box seemed to be in place of the red wire normally used in this application.
Is this safe to do?
 
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Old 07-13-07, 07:00 PM
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As for the setup, until I know exactly what you have, I can't comment on how safe or unsafe it is.

What type of boxes are used? How many cables exist? What wires are in those cables? How were those wires connected (before you did anything), to the best of your memory?
 
  #10  
Old 07-13-07, 07:00 PM
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DOTSON, the answer is "maybe". We really don't have enough information to know. Do you live in an area that uses cable, or an area that uses conduit?
 
  #11  
Old 07-14-07, 09:56 PM
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In the first box there is a hot wire coming in on the common and two travellers leaving to the other box.

In the second box, the two travellers come in and the and the common leaves to the light.

I was incorrect in stating that there were hot feeds coming into both boxes.
 
  #12  
Old 07-14-07, 11:33 PM
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Now that you know which wire is the common in each box, this is a piece of cake, right?
 
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