I know this question gets asked a lot, but I can't seem to make sense of this:

enter image description here Wires on the left: 2 sets of black/white/ground, one set coming from the light, and one set coming from the panel (I presume). The voltage meter does not register any current on any of these wires, so I assume these are load/neutral/ground wires.

Wires on the right: 1 set of black/red/white/ground coming from the light - what's confusing me is that both the red and black wires are live. The wires coming from the panel black/white/ground are have no current.

I am trying to hook up 2 new Lutron smart switches. Here is what I tried:

I am trying to install 2 Lutron smart switches, which require a neutral (I figure I just need to attach all the neutrals together).

Where I am mostly confused is line/load. It seems I have 2 line wires coming from the same light - and I imagine I will need to piggyback the left switch to the right, but which line should I piggyback on?

enter image description here

original pic

** Edit

This is not how I found it, I unfortunately did not take a picture prior to disconnecting - something I'll have to remember to do for future reference.

Those 2 black wires coming from the top were twister together, and if my memory serves me right, there was an additional pigtail wire connected.

All of the white wires were tied together.

The reason for investigating, is that when I connected my new Lutron switches, everything worked great for about 2 hours, but eventually the switch on the left stopped responding. I just assumed it was improper wiring (although now I wonder if it's not the switch itself because wouldn't improper wiring prevent it from working at all?)

I just tried re-adding the black wire pigtail to the top 2 black wires to create a line to connect to the switch (again I believe this is how it was previously), but what's strange is that now the white wire coming from the top left has become "hot".

This is in a kitchen, the switches control pot lights above the sink and below the cabinets.

The wire nuts in the back are ground wire extensions - the ground wire was too short to connect, so I added a length of copper wire to connect the extension together.

enter image description here

  • 1. Is this how you found it? With those particular 3 whites spliced together, and those particular 2 blacks? 2) What was connected to the bottom left black/white previously? 3) What was connected to the top center red previously? 4) What was connected to the bottom center black previously? 5) Do ANY of these wires (ignoring ground) cross over to the receptacle? 6) What are the wire-nuts back there capping off? Looks like grounds to me... Sep 19, 2020 at 15:16
  • Also, 7) are we in a bathroom, by chance? And 8) Is a heater one of the things that is switched here? Sorry for so many questions... you can edit <--click that, to add the details to your question. By the way, this is actually a fairly unusual one.... there's a LOT going on here... Sep 19, 2020 at 15:19
  • Just added some edits to help clarify
    – PT15
    Sep 19, 2020 at 15:54
  • 1
    Are you 100% sure that previously, all the white wires were tied together? It really matters... some people go "oh, I'm sure they would've been since they're all neutrals since they're white"... that's not necessarily so. Sep 19, 2020 at 17:47
  • If you know - did this box have two breakers that used to control it (different things in it)? Now that you have all of the whites separated in the second picture, you should do the same for the blacks, get a meter or a voltage line pen light, and lets figure out where you source(s) and loads are coming from and going to.
    – noybman
    Sep 19, 2020 at 18:39

1 Answer 1


Partial answer so we can knock out the easy part.

Grounds are super simple.

You do not need to run ground wires to switches if the mounting screws go through metal. Those ground via the mounting screws to the metal box. Any ground pigtails on the switches can be capped off, as long as the switch has a metal yoke. (where the screws go).

That doesn't work for receps, unless they're "self-grounding". It looks like that GFCI is self-grounding.

Therefore, all that's left to do is make sure every wire coming into the box is connected to the metal box. I see a generous 6 ground screws, so 1 per screw and you're done with grounds.

  • That is super helpful, I was never able to get a straight answer on that! It will help me tidy up that box as it was becoming cramped
    – PT15
    Sep 19, 2020 at 19:11

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