I was planning to replace a three way switch in my garage, but after replacing it, a section of my house went dark. I ended up replacing the original switch to do some troubleshooting. The problem is, I forgot how the original switch was wired. In the switch box, there is one hot 2 wire line coming in, one (not hot) 2 wire line going out, and a (not hot) 3 wire line going out. This makes me think that the switches are part of a circuit, leading me to assume that the non-hot 2 wire line was a continuation of a circuit (I can't think of another reason why there would be one hot line coming in and one non-hot line coming in).

Below is a picture of how I have it wired. The top right line is the hot line. The bottom left line is the non-hot line. The top left line is the 3 wire line.

enter image description here

The three way switch works, as expected, but the other section of my house is still dark. I've tried the following:

  1. Hooking the hot wire up to different lines, to see if that will continue the power.

  2. Running an external wire from this hot line to the next switch (six inches away) to see if that power source would power the switch (it didn't).

  3. Flipping each breaker in my house, to ensure they're reset.

  4. Face timing with my Dad (painful).

I'm honestly out of ideas. The goal at this point is to just replace the original switch and repair power to the other section of the house. If anyone has any other thoughts, I'd love to hear it. Thanks in advance.

  • The switch should be isolated from the rest of the house. Did you disconnect anything besides the three wires to the switch earlier? Is the nut on the blacks secure? – isherwood Oct 25 '16 at 13:58
  • Appreciate the questions. I disconnected it all because I was attempting to install an occupancy sensor, which requires a different wiring configuration. I'm 100% positive the nut on the blacks is secure and I'm 90% confident that this is how the switch was originally wired. I'm starting to think that something else is wrong, outside of this switch box. I agree that the switch should be isolated, I just don't know what that other 2 wire line is going to? What configuration would have two 2 wire lines coming into a box, along with one 3 wire? Thanks again for the help. – Tyler Oct 25 '16 at 15:09
  • First - it looks like a switch output is tied to the earth (bare)lines? bad. Second, take the switch out and fully disconnect it. Can you reset the breaker now? Third, never ever take something out without labelling each wire. The best you can do now is test each lead to see which one is the hot feed. – Carl Witthoft Oct 25 '16 at 15:13
  • It's common to have a home run come into a switch box, supply the lighting loop, and also pass on to a string of outlets or another switch loop. – isherwood Oct 25 '16 at 15:13
  • Hey Carl, it just looks that way. The common line is connected to the other blacks. – Tyler Oct 25 '16 at 15:15

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