In my garage (the other end of the 3 way switch) had four yellow 14 copper gauge wires used to connect this three way switch. Updating switch. When I tested the wires with a Klein clamp meter it appeared that only one of the wires is truly a traveler (no voltage) however it appears that the other three have voltage (20-120). I tried to spread the wires apart to make sure that there was no interference. I also used a no contact device which showed power on all three. I always thought that it doesn't matter which gold brass travelers go to and the load goes to the black on the switch. Again what do you suggest about the switch having four four yellow wireswires on a three way switch) All go to one same circuit breaker. What am I doing wrong with these four wires? The house 3 way has only three wires. How can I identify the other traveler wire? I tried to wire it the way they had it originally which I think was wrong. Why did they put a fourth wire in there anyhow?

  • Which conduit goes back tothe house 3-way? Apr 16 '17 at 2:37
  • Middle one which contains two wires. Oops, I forgot to mention that i have two garage lights which explains the 1st and 3rd conduit wires and the fourth wire which I wire nut the 1st and 3rd together with a jumper that goes to the traveler above the black brass. That explains the four double garage lights. But still why isn't it working. Apr 16 '17 at 14:54
  • Meant to say at the end.. that explains the four wire connection. Apr 16 '17 at 19:10
  • Your right -- two different power sources in a three way switch. Inside the house the common or power is the orange as the common. Those are the travelers that you had indicated in the garage. Apr 17 '17 at 15:05

It looks like the yellow one going to the 3-terminal Wago is the common from the nearby switch, and is supplying switched hot to the lights in the left and right conduit.

The other two yellows going into 2-terminal Wagos are travelers. The center conduit brings those, and also neutral, which is the return for the light, and two unrelated oranges that look like an unrelated switch loop.

Someone might send a memo to this electrician reminding him all those different colors of THHN wire are on his truck for a reason. Using the same color for common/switched-hot and travelers is kinda confusing.

  • Harper the 1st and 3rd conduit goes to the outside two garage lights which explains the fourth wire. The middle conduit has two wires leads to the house. Your right this was the way he did it forty years ago and didn't use a different color common. The black or common should be the power which comes to the middle conduit. Not sure why he didn't have longer wires inside the box originally. Apr 16 '17 at 15:07
  • @larrypinsky Interesting. Edited. Apr 16 '17 at 15:25
  • Didnt know that you can have two power sources for a common on a three way switch. The garage common came from the garage lights. The neutrals were in the middle conduit as ed explained. Inside the house he had the travlers connected to the three way switch with the orange wire as the common coming directly from the panel box. I understand that in the garage there were two switches (one three way and one for the inside garage light. In order to make both switches work in the garage, you had to use power from the outside two lights. Is this unusual or the way it is usually done? Apr 17 '17 at 21:46
  • By "common" I mean the terminal on the 3-way which is not a messenger. The common in the house 3-way is always hot, it controls which messenger is hot. When this switch matches, the common on this switch is hot, so it is "switched hot". That feeds the two lamps, and they return via neutral. Apr 18 '17 at 22:11
  • Your right--thank u again for a thorough explanation. Apr 20 '17 at 2:25

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