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Originally, there was a set of 3 light switches in one box. The 1st one switched my porch lights, the 2nd one switched my garage lights, and the 3rd was to switch an electrical outlet outside (used for Christmas lights). Each of these switches were hooked up with a live/line wire to provide the power + a load wire to pass forth the power to the light + a ground wire.

Now, the new smart (WiFi powered) light switches I am installing require a neutral wire. I found a bundle of 3 white neutral wires not connected to anything other than themselves with a wire nut. I know I can tap into this bundle of neutrals for the first 2 smart light switches, since they originate from the same areas where the live, load and ground wires originate from for the first 2 switches.

My question is about the third switch, as it has simply a live, load, and ground wire originating from its own separate area (not connected to any other wires/bundles). Please advise how I would get a neutral connection for the third light switch.

I've attached a picture showing the box with the three ground wires pointed down, the three live wires in the middle, and the three load wires at top. Farthest left column belongs to light switch 1, center column belongs to light switch 2, and the far right column (the isolated wires) belongs to switch 3.

BTW: I don't think they're on the same breaker, because originally I had switched off the breakers that I felt were sufficient for all the light switches, and when I returned to test the wires with a voltmeter I found that the third light switch's wires were still hot (while the first two were turned off). Then I went back to flip a few more circuit breakers off, and then finally the third switch's wires were no longer hot when tested.

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  • Are they all on the same breaker? Different breakers might not be able to do it, but on the same breaker, you can use the neutrals. I think they are the white bundle in the centre, but they need the same breaker.
    – crip659
    Oct 10, 2023 at 23:32
  • @crip659 i dont think they're on the same breaker, because originally i had switched off the breakers that i felt were sufficient for all the light switches, and when i returned to test the wires with a voltmeter i found that the third light switch's wires were still hot (while the first two had gotten turned off)... then i went back to flip a few more circuit breakers off, and then finally the third switch's wires were no longer hot when tested
    – Sonny
    Oct 10, 2023 at 23:40
  • If you end up unable to find a neutral, a few brands now make no-neutral smart switches.
    – KMJ
    Oct 11, 2023 at 0:12
  • The wire at bottom center appears to be white-painted over black insulation, yet is tagged "ground". Did you add these labels? Was that actually attached to a ground screw on one of the devices? If so, that seems to be exceedingly bad and a violation of not just NEC, but of every wiring standard in the world. Ground as Green or Green with a Yellow stripe seems to be the one world-wide wire color standard. Also, can you post a pic of the wiring with all the switches still attached in their original configuration - those "before" pics always help.
    – FreeMan
    Oct 11, 2023 at 14:45
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    @FreeMan the wire at the bottom center is actually bare copper with white paint marks (it only appears black due to the lack of camera lighting). I did add these labels. Yes this wire was attached to a ground screw, and it originates from a bundle of copper wires connected with a wire nut. I didn't take any pics of the wiring with original switches still attached
    – Sonny
    Oct 11, 2023 at 19:36

1 Answer 1

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You are correct to pause and think on this one.

I'm 99.99% sure that you have a switch loop for the switch on the right which is why you see one cable coming into the box for this switch and not one leaving.

I'd expect that when you disconnected the wiring to this switch, the black was connected to one terminal on the switch and the white to the other. If that's the case, then this is definitely a switch loop, the white wire should have had a black marking on it (black tape wrapped around it, black paint or marker colored on it, something like that).

In this case, the hot power comes from the panel (possibly via other receptacles) to the outdoor outlet. Then this one /2 cable runs from there to the switch. Power travels from the hot (black) wire at the outside junction box to the switch via the black wire you see here, then through the switch (when it's on) to the white wire and back to the receptacle's hot screw.

In this instance you do not have a neutral wire for this circuit and cannot install your neutral-required smart switch. You'll have to use that one elsewhere and get a smart switch that does not require a neutral.

Notes:

  • You CANNOT "borrow" neutral from the other bundle of neutrals in the back of the box because they're on a different circuit. Crossing circuits is not only against code, it's dangerous.

  • You should strongly consider cleaning the paint off the wires to make it easier to identify what's going on. Future you will appreciate the effort now. Working with one wire at a time (or one bundle under a wire nut):

    • Gently drag a utility knife blade across the wire (dull edge of the blade toward you, sharp edge away and touching the wire, pull the knife toward you - like you're buttering toast). The blade will scrape the paint off without cutting into the insulation
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  • the white wire labeled as "live" was connected using the "back stab" push in connector on the bottom of the light switch, and the black wire above it labeled as "load" (you cant see this label from this camera angle) was connected in the push in connector on the top of the light switch. this is the same configuration/setup for how all the other wires connect to other light switches; so they're all loops? using a voltmeter i confirmed the wire i labeled as "live" indeed was hot, and the one i labeled as "load" had no power. this switch controls power to an electrical outlet on an exterior wall
    – Sonny
    Oct 11, 2023 at 20:41

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