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bergs4 · Jul 26, 2009, 09:12 PM

Hello,

I am in the process of replacing two three-way switches that control a receptacle. Stupidly, I didn't label the wires on one of the switches before I removed the switch. In addition, the box that used to have a three-way switch which I removed, has four (not including ground, which I don't have) wires going into it. My question -- how do I identify the wires properly. I have an included a picture of the box in question. Also, if it helps -- on the other switch, the person who wired had two wires connected to one screw (which I know shouldn't be done) so I'm wondering if that might be what they had done here.

Thanks.

hkstroud · Jul 26, 2009, 10:28 PM

Can't tell for sure but that looks like two 2 wire cables to me, not a 3 wire cable.

Describe wiring at other switch. Determine which wires are on common screw. Also check what wiring you have at outlet. You are going to have to trace this one down, looks like someone used two 2 wire cables as a substitute for not having a 3 wire cable.

Stratmando · Jul 27, 2009, 06:08 AM

With switches out of both locations, look for a hot wire, this will go to common of 1 three way, then connect the other 2 wires to that same switch.
Turn that switch up and see which wire goes live in the other box, then switch down and see what goes live in the other box, these are the 2 travellers, connect to traveller screws, wire left over should go the common screw and should be the wire that goes to the receptacle. The 2 wires should be connected with a pigtail so 1 wire is around screw.
Extra wire could be a hot to feed a receptacle, switchleg to other lights? Will have to hook up three ways and see what doesn't work, then troubleshoot that.
A Note: 3 way switches use no Neutral's, don't have to worry about sparks from wrong wires connected.
You can twist all wires together in both boxes and it will not trip breaker, the 3 way switched load will be on.

bergs4 · Jul 27, 2009, 11:32 AM

Great. Thanks for the answers.

hkstroud · Jul 27, 2009, 06:47 PM

No fair, the rules say you have to tell us the end of the story. Let us know what you fine and how you make out.

bergs4 · Jul 27, 2009, 07:03 PM

My bad.

After spending the good part of today working on this, I thought it was going to be time to call an electrician because, going on the assumption that the cable containing two wires (the two wires on the right in the picture I sent) was the traveler, I ended up being able to control the receptacle from only this switch. The other switch, whose wiring I duplicated exactly from the original, did absolutely nothing. So, after much grumbling and a few expletives, I thought that I should try different wiring combinations since you guys said there was no neutral in three-ways, and I didn't have to risk a short cicuit. So, first I thought that the wires I had initially pigtailed together and thought were the common might in reality be one of the travelers. That didn't work. Then, I figured I should try a different combination. This time I connected the two individual wires (the ones I originally thought were the common) to the traveler screws and pigtailed the other two wires in the box (which I originally thought were the travelers) and connected them to the common screw. I was shocked (not literally) to find out that that the switches now worked.

Thanks so much for everyone's help along the way!

hkstroud · Jul 27, 2009, 07:35 PM

Good show. So I was correct that two 2-wire cables were used as a substitute for a 3-wire cable.e

Stratmando · Jul 28, 2009, 06:06 AM

Was the method I described helpful? Usually it does not take all day, will have to rewrite if confusing?

bergs4 · Jul 28, 2009, 09:48 AM

Stratmando -- yes, your post was very helpful. In fact, determining which wires were hot (as you suggested) when switches were flipped helped me to realize that I had it wired wrong initially. I guess it took so long because I was so convinced that the two wires in one "cable" had to be the travelers. I'd rate your answer if it'd let me.

Thanks again.