I have switch box that controls my under cabinet lights. I was replacing the lights themselves and had issues with them working, started troubleshooting and found that there is a single hot white wire (out of 4 total) in the box. The hot white is in the same 3 wire cable (black/white/ground) as the hot black. Pictures below for reference:

wide view (hots are capped/circled

zoomed view of both hits coming from same cable

The circuit also includes two single pole switches and one 3 way switch.

With the neutrals nutted together I get a hot white/black wire to one of my under cabinet lights, which causes the rest of them to stop working.

Any idea as to how to resolve?

  • What happens when you nut the hot white and hot black together? This looks like a switch loop to me... Oct 25 '20 at 14:50
  • 1
    Can you restore the wiring to the original way it was wired before you disconnected everything?
    – JACK
    Oct 25 '20 at 16:11
  • There is some pretty significant damage to the insulation on that black wire to the left of your red circle. Significant as in scraped all the way through the insulation and bare copper showing! I don't think that wrapping it in electrical tape meets code, but I hope you at least did that!
    – FreeMan
    Mar 25 at 12:02

A hot white wire is normally part of a switch loop. The white being always hot keeps it from being confused as a neutral. After you read this entire answer If you connect the black and white on that cable it will probably activate a light or garbage disposal or another device in a kitchen. Please read the last sentence prior to trying this.

I hope you have that mess of wires labeled in some way we can’t see. With that number of wires it may be tough figuring out what is what.

Just a note I counted 10 wires that with a device would require a 24 cubic inch box with 14 awg wire minimum. The box doesn’t look extra deep but even a deep single gang box I think tops out at 18 cu inches so your box is grossly over filled (a 3”x 2” x 3-1/2” box is 18 cubic inches). If there are clamps I can’t tell but plastic doesn't always have clamps.

Don’t connect the always hot white to the other whites, if it is a switch loop when you do this the breaker should trip when you connect it to the other whites (“the lights stop working”) If that is what is happening try connect the black and white of that cable together and look for what turned on.

  • When I connect both the hot neutral (white) and hot line (black) wires together nothing happened (no breakers tripped, no sparks, etc.). I pigtailed the line from my smart zwave switch to the capped hot white/black, then did the same for my neutral and the load (to the corresponding black/white wire bunches) and the current appears to be coming into the switch and going straight out the neutral. The load is not hot regardless of the switch setting, and the light on the switch (typically a small blue light indicating power) is not illuminated.
    – DWood
    Oct 25 '20 at 20:18
  • Also, two of the under cabinet lights have hot neutrals, one each out of two neutrals coming to each light. That leaves one other neutral running somewhere that is now also hot, however not sure where it goes yet. None of the other light switches identified previously in the circuit are working either. I am going to swap switches to rule out a faulty switch and will try to identify the other hot neutral if at the other switches.
    – DWood
    Oct 25 '20 at 20:20
  • Update: I found two other switches on the same circuit and there was a hot neutral capped off by itself in that box (dual switches). Both of the light switches work in that box without issue. I tried capping the hot neutral in the single switch box in the same way and it didn’t change anything.
    – DWood
    Oct 25 '20 at 21:17
  • If I Follow you you may be reading a phantom voltage on the neutrals but that would not explain why the lights quit working when you connect the “hot” white to the neutrals , if the white is hot it is not a neutral, it may have a phantom voltage on it, the other case is if this is a multiwire branch circuit that separates prior to this location (a handle tied pair of breakers or a double pole breaker with a single handle) could be why you are seeing voltage on the neutral if you are checking with the breaker on and there is something on the other circuit you will see the return on the neutral.
    – Ed Beal
    Oct 25 '20 at 22:03

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