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I have a TP link HS220 dimmer switch that appears to be working correctly with the Phillips 8w LEDs I have. It goes on/off min and max dim with no issues. However, when I turn off the switch there is a slight glow coming from the LED light. This dimmer controls 2 LED lights and you can see the faint glow on one of the lights. :(

The way I installed this is not typical because the circuit actually goes to the light 1st then to the smart switch, so at the switch I have a 14/2. I have the black going to the hot screw and the white wire going to the load. Luckily this switch is installed on a 2 GANG box that also has a fan switch. The fan is using a 14/3 wire and one of the wires is no longer being used by the fan. This was the wire that controlled the fan light. So I took this wire and connected it to the neutrals at the fan box in the ceiling and then connected the other side of this wire to to the smart dimmer on the neutral pigtail (both wires go to the same breaker). Again, all appears to be working but when the switch is completely off, you can see a glow coming from the LED light.

I'm trying to determine if its my wiring that is causing this glow or if its the switch. I'm not an electrician and would appreciate any help in trying to figure this out.

TIA, P

Update, I did eventually get rid of the faint glow with a better bulb. I used the GE reveal 10w BR30 and this removed the glow. I also realize I have some code violations the way I wired things. Since I have no neutral I will be moving to a Caseta dimmer at some point and removing the TP link .

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  • Quite a few questions on this already. Have you done some reading? diy.stackexchange.com/questions/133558/…
    – isherwood
    Dec 22 '20 at 15:33
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    As an electrician I cringe when I hear or read things like this with multiple code violations (white going to the load with the feed in the ceiling , using a neutral from another circuit) This is a diy site but you should really get things wired correctly and safely first. This may even fix the problem, that or get a smart switch that uses the ground not the neutral.
    – Ed Beal
    Dec 22 '20 at 16:54
  • get a better/newer LED bulb, one with a built-in load resistor for dimmer compat.
    – dandavis
    Dec 23 '20 at 0:16
  • So I did get a better bulb a GE reveal 10W and that seems to get rid of the faint glow. I realize that I did not do this to code. I will most likely move to a caseta switch instead of the tp link. Thanks for your responses and suggestions.
    – Da P.A
    Dec 23 '20 at 22:38
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I can't say for sure why you have that LED glow. Typically that is due to deliberate power leakage through switched hot for a switch that doesn't require neutral. However, this switch requires neutral and you have described a wiring installation where it gets neutral. So the mystery remains. But you have bigger problems.

The neutral/hot/switched hot need to be together. Not going to immediately cause a big problem in your current (pun intended) setup because LEDs don't use much power, but definitely against code and not good long-term. In addition, you very likely have a color-coding problem.

Here are the key things:

  • Neutral must run together with the other wires of the circuit. In some cases you don't need neutral - that's why your switch loop didn't have it. New code requires neutral at switches to take care of this problem, but old wiring is grandfathered. Grandfathered wiring takes care of the code issue until you actually need the neutral! So for this setup, you either need a new 14/3 cable to replace the 14/2 (so you can get the correct neutral) or you need a switch that doesn't require neutral.
  • Wherever you do get neutral, it must be white or gray (or grey). Based on your description, you very likely repurposed an unused red or black wire to be neutral. You are permitted to use a white wire in a cable as hot or switched hot under limited circumstances, but you can't use a colored wire as neutral.

Part of the problem is that historically dimmers, timers, etc. would leak current through switched hot to power themselves. That works great with incandescent lights. With LEDs, that results in either a glow or (even worse) blinking. The solutions are:

  • Battery - You have to change it periodically.
  • Neutral - You have to get a neutral in the right place (as you found out the hard way). Which is why code now mandates neutral in switch boxes.
  • Ground - Permitted under limited circumstances when designed properly and approved.

End result: You may need a different switch. But if the switch (this one if the problem can be fixed, or another one) needs neutral, then you will need a new cable - you can't grab a neutral from elsewhere, even though it is on the same breaker/circuit.

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    Thanks for taking the time to answer, I did suspect that this was not up to code. I did indeed repurpose the black wire that was not needed for the the fan light as the neutral. I did suspect what i did was not code however I can't figure out why there's a glow on the LED still. Could this leakage from nearby wires? or maybe a bad switch? Most likely I will change that to a lutron caseta switch that does not require a neutral and you can still control with alexa etc with the hub. I just can't figure out how im getting the glow even with a neutral, although i know its not up to code.
    – Da P.A
    Dec 22 '20 at 17:36
  • Don't know why the glow - and I know that was the original question! Be careful on the Caseta - see if it specifically says anything about how it gets power. If it absolutely requires a ground wire then that is an indication it uses ground. If it does not require ground and/or neutral (i.e., no neutral required and no "if you don't have neutral you must have ground") then I would expect it to "leak current through switched hot" and have the same problem. If you have a specific model # you are considering, post that and we can look at the specs. Dec 22 '20 at 17:38
  • thanks again. I actually purchased the P-BDG-PKG1W after reading your original post. I believe this requires no ground.
    – Da P.A
    Dec 22 '20 at 18:19
  • The P-BDG-PKG1W does not require ground or neutral. However, that leaves open the question of how it gets power. While it claims compatibility with dimmable LEDs, I would be concerned that there is a good chance it uses leakage current to get power, which would very possibly lead to "glow" or "blinking". Something that REQUIRES GROUND but does not require neutral might actually be a safer choice, provided you have ground available. Dec 22 '20 at 18:31
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    By "leakage", I do not mean "like a pipe that drips when it is supposed to be totally off". It is a specific term referring to a device (switch) deliberately passing some small amount of current through the circuit. That should not be the case with a switch that uses neutral, but I raise it as a possibility because with a switch that does not use neutral or ground it is very, very likely. Inductive coupling is certainly a possibility, though there really shouldn't be much for that to happen from when the switch is "off". Dec 22 '20 at 19:57

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