So I got some smart switches (Kasa HS210), and being relatively handy thought I could wire them up alright, but I guess I'm in a bit over my head due to having a "dead end 3-way"? Using the original switches I was able to control lights at both ends, but with the smart switches, not so much. They either fail to work, or result in the lights rapidly switching on and off, depending on how the wiring is.

Incoming line junction box has 4x cable runs, but only one has a red traveler wire, which matches up with the downstream dead-end. Not 100% sure where the others go, but I'm assuming to the lights themselves and my back patio since that turns off when I switch the breaker off.

I think I have the line side wired up correctly, but I'm at a loss as to what to do at the dead-end side of things. I've seen mention of using the neutral as a common wire on the dead-end side, but I'm fairly sure my switches require a neutral.

Appreciate any insight

Original line side wiring Original line side

New line side wiring Incoming line

New dead-end wiring (confident this is nowhere near right...) Dead end

  • 3
    "neutral" should never be a "common". But "white" might be a common wire. There are a lot of different 3-way wiring combinations. What you really need to do is to put back the original switches so that they work as before. Then take pictures showing the wiring, which at least at that point is "functional" even if not perfect. Then there are ways to figure out piece by piece what each wire does. And then it should be possible to replace with smart switches. Note that not all smart switches will work in all situations, due to need for neutral (sometimes) and/or other reasons. Nov 8, 2023 at 3:52
  • It appears I only took a photo of the line side before i unwired everything :( attached it though
    – Havegooda
    Nov 8, 2023 at 4:08
  • 1
    Without ba reference photo the only way to be sure is to go through with a meter and figure out which wire is doing what. There are some smart switches which can handle some three way setups, but until you know the wiring you can't guess which might work and/or how to configure them. Sometimes the simplest answer is to put a smart switch at one end, put a switch transmitter at the other, and link them in the home automation. (Or just call for the smart speaker to flip the switch for me.)
    – keshlam
    Nov 8, 2023 at 4:33
  • Is this house wired with aluminum? Are the switches aluminum rated? Nov 8, 2023 at 20:07
  • That's aluminum wire and you seem to be completely ignoring that fact and carrying on as if it's copper wire. It's possible to work with aluminum (it's not that bad) but you have to know what you're doing and get it right. You're going to need some Alumiconns and a torque screwdriver. Nov 9, 2023 at 19:17


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