I'm trying to swap out an existing two way combo switch with a new. When I pulled it out, the right side terminals had three wires. Two black and a red. On the left side there was one black. My new outlet only has space for two wires on the right and left. How do I wire properly? Thanks, new hereenter image description hereenter image description hereenter image description here

  • Can you post photos of the situation with the old switch, as well as the make and model of the new switch? Also, where are you on this planet? Mar 23 at 0:01
  • Yes I'll get a photo when I get a chance. But it was in the order, top down, black, black, red. Mar 23 at 0:05
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    Where are you on this planet, for that matter? Mar 23 at 0:06
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    Three "hot" wires and 1 "load" is incorrect for that switch. The source data is wrong or misinterpreted. Your question about red wires may explain all this: you are expecting hot wires to be color-coded by function. Doesn't work that way. Hots are any color other than white/gray (neutral) or green/bare (ground). If you want them color coded, you can retape them colors after you identify them; I do exactly that. Mar 23 at 1:27
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    Photos added in original post. The combo switch goes to a pantry and the garage light. When I wired the new outlet without the red, the garage light didn't work, so clearly goes to garage. and now that I notice it, the garage light also has switch out by the side door in garage. So perhaps that's my problem, I need a three way combo switch since that light is controlled from two switches. Mar 23 at 19:55

You need to return the switch you got and get a single-pole/3-way combination switch instead of a single-pole/single-pole

Your existing combination switch has a normal single pole switch on the top and a 3-way (two location) switch on the bottom, while it sounds like your new switch consists of two single pole switches, which won't help you with your garage light very much. So, as you are suspecting, you'll need to take it back and get the correct thing; fortunately, it shouldn't be that much harder to find.

As to how this was wired

The good news is that we can identify the functions of the old wires from here. Clearly, since the black wire on the left is shared between both halves of the old switch, it must be the always-hot feed in. From the terminal screws on the right, the top one is connected to the black switched-hot for the light controlled by the top (single-pole) switch, while the bottom two screws connect to the black and red wires that serve as the travellers to the garage light.

You'll need to remember what these wires do, though, since the positions of the screws on the new switch isn't going to help you any, only the fact that the common screws on said replacement will be a different color. Also note that NEC 404.9(B) permits snap switches to be grounded by their screws, so don't worry about running a grounding pigtail to your switch.

  • Thank you very much, that's helpful. Once I realized there was another switch in the garage today I figured it was a three way (recently bought the house so still discovering). Mar 24 at 0:29
  • @Diyhomenoah -- we thank people around here by upvoting and/or accepting their answers :) Mar 24 at 0:30
  • No clue how to do that, would be happy to. Just joined Mar 24 at 15:03
  • @Diyhomenoah -- there is a score, up/down arrows, and a grey checkmark on the left side of questions & answers here (the checkmark accepts answers, the up/down arrows do what you'd expect to the score) Mar 24 at 23:01

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