I’m trying to replace a single pole switch in my room that is used to control a single ceiling light. The replacement switch is a smart switch. However, after taking a look, it seems the wiring isn’t as straight forward as I hoped.

There’s 3 separate cables coming into the box. Each cable has a black wire, a white wire, and a copper ground wire. The ground wires are all fastened to the back of the box, the black wires are all bundled together on the side with a cap covering the ends of all 3, and 2 of the white wires are bundled together with a cap as well as a separate white wire that joins the two to the switch. This leaves one more white wire that is going directly from one of the cables to the switch.

In summary, none of the black cables are connected to the switch but all of the white cables ARE connected to the switch. I checked with a voltage detector and all of the black wires are hot. The 2 white wires that are bundled together and then connected to the switch are never hot, neither in the on or off position. However, the white wire that isn’t bundled and connected to the switch is hot when the switch is OFF not on.

Can anyone explain to me what’s going on here? Here are some pictures:
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  • 1
    Somebody was a very bad boy and switched neutral instead of hot/live. Every time you changed a light bulb with the switch off, you were inch away from live power. Turn off the breaker and post pictures of the wires at the light and switch, without removing/disconnecting any.
    – crip659
    Jul 20, 2023 at 22:39
  • I’ve added some pictures of the switch wiring. If necessary, I’ll try and remove the fixture off the ceiling and take pictures of how that is wired too.
    – Jack
    Jul 20, 2023 at 22:57
  • That purple wire nut is a red flag - you may have dangerous small branch-circuit aluminum wiring.
    – nobody
    Jul 20, 2023 at 23:23
  • 1
    @nobody The photos show copper ground wires so the insulated wires can’t be aluminum. It’s a mess but not for that reason!
    – DoxyLover
    Jul 20, 2023 at 23:47
  • The way the wires are connected at the light will lead to the proper fix/answer for this. Hopefully it just switching wires around to their proper place.
    – crip659
    Jul 21, 2023 at 0:05

1 Answer 1


That's an illegal wiring arrangement: the switch is wired to switch the neutral for some reason.

That all needs to be corrected, just for general safety. Any competent handyman should be up to the task; I wouldn't even think you'd need a proper electrician.

Correcting it is also a prerequisite to installing a smart switch. It cannot be installed with the wiring as it is because they're not designed for switched neutrals.

  • A switch does not care if it is neutral or hot that it is switching it will work fine. The code and common sense tells us it must be the hot side.
    – Gil
    Jul 21, 2023 at 7:46

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