I have a 3-gang box with the following 4 cables that I need to wire up 2 indoor lights and remove 1 outdoor light from the circuit. (I plan to connect the outdoor light up to a different breaker switch) But I can only get 1 light to work with a dimmer and the other can only be permanently on.

  • 1 cable from the breaker with black, white, and ground wires

  • 1 cable to an outdoor light with black, white, and ground wires (this I'm removing from the circuit)

  • 1 cable to a kitchen fluorescent light with black, white, and ground wires

  • 1 cable to a dimmable dining room light with black, white, red, and ground wires (I know this is part of a 3 way light with 1 other switch I've correctly set up)

I want to hook these lights up the following way to Lutron Caseta smart switches/dimmers

  • remove the outdoor light from the circuit (I think I can do this by just disconnecting the outdoor cable wires and capping them)

  • connect the kitchen light to a Caseta PD-5WS-DV Switch

  • connect the dining room light wires to power from the breaker (it's already connected to a Caseta Dimmer at the gang box at the other end)

All the white neutral wires are currently connected. And all the ground wires are currently connected.

When I connect the black breaker wire to only the dining room black and red wires, the dimmer works.

The problem is when I attempt to connect the kitchen light up to the Caseta Switch. The kitchen light doesn't come on and the switch LED doesn't turn on. But if I connect the black breaker wire directly to black kitchen wire, the light is on permanently.

  1. Why isn't the switch working with the kitchen light?
  2. How do I disconnect the outdoor light cable from this circuit?
  3. How do I connect the dining room wires and the kitchen wires to the breaker wires so they work together (and is that in series or parallel)?
  • What color is the status light on the Caseta? Also, where are you planning to connect to this different circuit at? Commented Aug 5, 2020 at 2:18
  • @threePhaseEel I plan on connecting the outdoor light in the same gang box but I'll bring in a new cable from the breaker. Is that allowed to have 2 cables coming in from the breaker in the same gang box? Commented Aug 5, 2020 at 17:31
  • Yes, that's fine, as long as you maintain a "Chinese wall" between the two sets of neutrals in the box Commented Aug 5, 2020 at 23:22
  • @ThreePhaseEel what is that wall? I Googled it but didn't find anything. Commented Aug 6, 2020 at 4:44
  • It's a figure of speech for having to maintain a hard division between the two sets of neutrals -- you can't cross the streams here, or else you'll create EMI and the risk of overloading a neutral wire Commented Aug 6, 2020 at 11:41

1 Answer 1


The first thing you do is roll it all back to status quo ante with the original switches and get it back where it works 100%.

Now you'll see a black wire that is split to go to at least 2 switches. (it may pogo from switch to switch). We're not worried about that one for now, but its function is always-hot. We'll be spending most of our time with the other wire on each switch.

The outdoor light

On the outdoor light, pull the (remaining) wire off the switch that controls it, and cap it off for good. It's done.

Identify the neutral wire that is the partner to this hot, and make a mental note to cap it off also, later.

Hot or not

Notice that the 3-way switch has 2 brass and 1 black screw. The 2 brass screws are the travelers. 3-way circuits work by making one traveler hot and the other traveler not hot.

Pick a brass screw and take the traveler wire off it. Cap that wire off for good. It's done.

Now, take the traveler wire on the other brass screw, and wire nut it to the (common) wire(s) on the black screw.

See what we did there? We made the first traveler not and the other traveler hot.

That's it; the 3-way switch goes away.

The kitchen switch

This Lutron switch is neutral-less, which is unfortunate because you seem to have neutral present, and this choice will require you to add an additional module called a LUT-MLC to effectively simulate neutral.

At this point one wire remains (that isn't capped or always-hot).

Now we take that single wire and join it to two things: a) one of the black wires on the Lutron switch, and b) one of the two wires on the LUT-MLC module. So 3 wires come together.

The other wire on the LUT-MLC module gets added to the bundle of neutral wires. While you have that bundle apart, remove for good the neutral that is the partner to the outside light you just capped off.

The remaining black wire on the Lutron smart switch needs to be added to the "Always-hot" bundle. This is a good time to get rid of any unused pigtails etc.

Lastly the ground wire must be added to the ground bundle.

  • Thank you! Once I followed these, it became obvious that the Caseta Switch wasn't working so I swapped that out and it works now. Thank you for your very detailed answer. Commented Aug 5, 2020 at 17:34

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