I'm by no means a professional but I've switched out plugs before (we wanted white instead of almond) so I thought installing a new zwave light switch would be the same. I installed it fine, the switch works, however, we've noticed two other light switches no longer work (one in the kitchen and one in the closet, they do all share a wall). Is it possible for that new switch to cause the others to not work like that? It doesn't seem like it but again I'm no professional.

I did turn off the power to the house via the main switch to install the zwave switch. I thought maybe I tripped the breaker they're probably both on but I've switched every breaker on and off already and that didn't seem to fix anything. Any ideas?

Edit added photos: Photo of the old electrical switch New Switch New switch with wires Wires More Wires

  • Can you post a photo of the inside of the switch box in question? Jul 2, 2018 at 22:20
  • @ThreePhaseEel The only photo on my phone is of the old switch. I posted it, but I'll get a better photo of it tonight.
    – Jim
    Jul 3, 2018 at 12:32
  • I don't see a neutral (white wire) in your photo of the original. Z-Wave switches are powered themselves and require a neutral. Are you sure there's a neutral in that box?
    – Machavity
    Jul 3, 2018 at 13:08
  • @Machavity Yeah it's a bad photo. I only cared about which wire was going into the old switch as a reference. I had to cut the old nut off the neutral(white) wire and then strip the wire to get the neutral wire into the zwave switch. The zwave switch works fine (even got it working with a motion sensor at the end of the stairs), it's the other two dumb switches that were working fine before no longer work.
    – Jim
    Jul 3, 2018 at 13:27
  • @Jim Did you put a new nut on the neutrals? Jul 3, 2018 at 21:18

3 Answers 3


While looking at your picture makes it difficult to tell how you wire nutted the wires in for your new switch (those neutrals are in the way - if only they were pulled out so we could follow the wiring back to each connection). That said I will take two stabs at the issue here and the problem is most likely one or the other.

Your Z-Wave should be configured like this:

  1. Line In : Bottom Left.
  2. Neutral : Bottom Right.
  3. Load : Upper Left.
  4. And if it has 3-Way traveler : Upper Right.

The most likely scenario I suspect is:

Perhaps when you added in that Neutral Line for your Z-Wave you did not get all of those neutrals together in the wire nut very well - I have known this to happen to people not just on the neutral but the hot side as well - the line in side just did not get wrapped up with all of the other wires , because the installer simply added one wire and tried > to use the same wire nut, which was fine before but a tad too small now and the wire slipped down a bit and did not make connections with all wires.

Another possibility is:

Perhaps you disconnected the line in that would be considered the power distribution line serving all 3 of those switches and then you attached it to the load side of your Z-Wave?

  • It's possible my neutral line nut is too small and one of the wires fell out, but would that cause the switch to work fine but others on the same breaker fail to turn on?
    – Jim
    Jul 10, 2018 at 20:23
  • @Jim yes .. your neutral wire that is actually making contact is working for your z-wave; the down line neutral is not connected and therefore those other circuits (closet , kitchen) are not getting the return path neutral line, they are free floating. Get a one size up wire nut at HD (some are color coded for sizing). Open that wire nut up and put the proper size wire nut, I am thinking a RED it should say on the package:Gauge, Min-Max number of conductors (looks like you have 4). Old house the wire is probably 12 Gauge (Larger Diameter), new house it is probably 14 Gauge (smaller diameter).
    – Ken
    Jul 10, 2018 at 20:48
  • Ok thanks. Gives me something to try tomorrow night.
    – Jim
    Jul 10, 2018 at 23:17
  • @Jim Glad that fixed it for you.
    – Ken
    Jul 12, 2018 at 0:36

The neutrals were definitely never reconnected properly, or only the incoming neutral at the z-wave switch was used, rather than a link from the bunch of neutrals. Once you break the line in the circuit, whether it be neutrals or “hot” wire (as you call it in the US) then every component down-stream from that point in that circuit will not work.


There is a chance that the actual switching component inside the zwave switch is feeding back onto the shared wires to the other bulbs preventing them from starting. If they are energy saving bulbs, florescent or led try old filament bulbs in place of them to rule this effect out.

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