I'm having trouble installing a WEMO wall switch. The light I want to use it on is a single on/off switch, not a 3 way switch. When I remove the face plate, the neutral wire is wired to the light switch on its own. It's not connected to the other neutral wires that fit in the multiple light switch housing. I have tried connecting but it does not function. What does it mean when the neutral wire is connected to the light switch itself and not bundled with the other neutral wires?

  • Are there other switches/wires in this box? A labelled picture may help here.
    – gregmac
    Commented May 1, 2014 at 15:19
  • 1
    Duplicate? diy.stackexchange.com/questions/10427/…
    – Niall C.
    Commented May 1, 2014 at 15:28
  • @NiallC. while your reference does describe basic switches, this OP is asking about an active switch that may need a neutral.
    – bib
    Commented May 1, 2014 at 15:54
  • 2
    Be careful! Multi-gang switch boxes can have 2 or more circuits passing through them, and it sounds like yours does.
    – Rand
    Commented May 1, 2014 at 16:27

1 Answer 1


If all you have is one wire entering the switch, then the power for the switch might come from the light, and you just have a switched hot.

enter image description here

The white wire should be marked with tape to indicate it's not being used as a neutral.

Unfortunately, if this is the case, then you don't have a neutral available at this switch which is necessary for most of these automation switches. If there are other switches in this box it might be possible to re-route the power for this light, but I'd need to know more about where the power is coming from, what else is there, and how the light is connected in the ceiling box to help. Otherwise, the only way to this would be to run a new wire to the switch location -- either a new 14/3 from the light (so you have hot, neutral and switched hot), or a new power feed with 14/2 from the panel.

enter image description here

  • 1
    Just a comment on this marking of white wires, and I’m not directing this to you @gregmac in any way. But I saw a mention of this on another question and now again and I feel I need to elaborate. The safest approach to building wiring is to recognize, “There is no color coding”, and so any wire regardless of its color can have any electrical potential. The same logic in healthcare is called, “Universal Precautions”, where you treat everyone as if they have every viral or bacterial infection there is. To imply that white wires are safe unless they have tape on them is dangerous, and it surprise
    – Rand
    Commented May 3, 2014 at 13:07
  • I agree with Rand that you should not assume that an unmarked white is a neutral. However, he seems to be implying that one should therefore NOT mark white wires serving as hot, so as to -what?- prevent a false feeling of security around unmarked ones? Go ahead and mark the hot white wires you DO find (there shouldn't be too many) and eventually all of them WILL be correct.
    – user38753
    Commented Jun 23, 2015 at 14:49
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    Agree, don't make assumptions (especially if you've ever found anything else not to code in the house). However in this case, when there are only two conductors in the box, both going to the switch, and the switch is working to turn the light on and off, they must both be hot (or both neutral, if someone really got things messed up elsewhere). Either way, not possible to install a "smart" switch that requires hot+neutral.
    – gregmac
    Commented Jun 23, 2015 at 19:12

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