3 way switch with extra 4th wire

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  #1  
Old 01-06-15, 12:38 AM
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3 way switch with extra 4th wire

Hello all and thanks in advance for any help.

I have a 3 way switch that is not working, so I thought I would just replace the switch. However, when I got it pulled out I found that there was an extra 4th wire present. (2 black, 1 white, 1 red)

The set up on the old switch was this:
First black wrapped around Common Screw. Second black pushed through back port of Common Screw. White and red each to brass terminals.

I am not able to repeat the exact set-up because the wire is 14 gauge and the newer switches only allow for 12 gauge wire in the push-in terminals. So, I did the next closest thing and wrapped both black wires around the Common Screw (yes, I would have gone back and pigtailed them if it had worked, but it did not).

Since it did not work, I am at a loss as to where I should put the extra black wire. I do understand the concept of a 3 way switch having one Common wire and two travelers, but do not know what to do with the forth wire.

I should also mention that I just bought this house (built in the 50's), so not sure when the switch last worked properly, although none of the work seems "new".

Again, thanks in advance for any advice! It's much appreciated!
 
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Old 01-06-15, 02:40 AM
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Welcome to the forums! Are you sure it is a 3 way switch set up? How many locations control the lighting in question? In what manner were the wires connected to the original switch? Don't use the push back connections. Use the screws. If two wires were under one screw on the original switch, pigtail them to the screw head. Do you have the original switch? How many screws were on it, not counting a possible grounding conductor?
 
  #3  
Old 01-06-15, 04:01 AM
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The push in terminals are for #14 only, not #12.

The old setup was using the device to effectively splice the two blacks together. Your setup is wrong because the rule is one wire per screw. Pigtails need to be used.
 
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Old 01-06-15, 04:45 PM
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I am fairly certain it is a 3 way switch. It is a pretty small kitchen with one switch at the back door and one switch near the dining room, so it would be pretty silly to have a third switch somewhere.

I do have the original broken switch. It has one common screw and two brass screws.

The set up on the old switch was this:
First black wire wrapped around Common Screw. Second black pushed through back port of Common Screw. White and red each to brass terminals.

Thanks for your time!
 
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Old 01-06-15, 04:58 PM
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That is a classic 3 way set up with a "through" hot wire. Pigtail the two black wires and attach them to the black screw. Red and white to the brass screws.
 
  #6  
Old 01-15-15, 06:00 PM
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I just tried pigtailing the two black wires and it is still not working. Any other ideas?
 
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Old 01-15-15, 06:16 PM
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I just tried pigtailing the two black wires and it is still not working.
What isn't working? The light it controls or the load it feeds?
 
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Old 01-15-15, 06:35 PM
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I just bought this house (built in the 50's), so not sure when the switch last worked properly
It may have never worked properly. Sometimes in the 50's a 3-way switch would be wired to where you could turn on a light from two locations. However, it was dependent on the other switch position. This isn't true with modern wiring and 3-way switches, either switch will always turn on and off the light.
You may want to post pictures of both switch box wiring, and light wiring.
 
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