Wiring help with a double gang 3-way install

Hello! I just got two Blue switches (VZM31-SN) and am installing them both into a double gang box. The switches that I am replacing used to be dimmers. They are both in a 3-way configuration, and their dumb switches are located on the other side of the room in a triple gang box.

I have a neutral wire, so I want to use the inovellis on one side, and keep the old dumb switches on the other side.

The two switches are for my living room, and my kitchen. They are all on the same circuit.

The Double Gang Box: (This is where I would like my inovellis)

Here, the left switch controls my living room, and the right switch is my kitchen. I have already successfully installed the Inovelli on the left, and it functions as normal in 3 way mode with it’s dumb switch. The red is traveler, white is load, black is line, and other white is neutral.

The problem is this switch on the right, I’m not exactly sure what is going on or how to wire it. From the wall I have 3 wires that the previous (dimmer) switch was using. A flagged black wire (on top in the image), a black wire, and a red wire. I tested these wires with a no contact tester and found that:

  • The flagged black wire never has voltage
  • The black and red wires swap voltage based off of the state of it’s dumb switch.

The Triple Gang Box: (Where the dumb switches are)

Here, the switch on the left controls my kitchen (so the one i’m confused about), and the one on the right controls my living room (functions correctly with the Inovelli). The middle switch is a dimmer switch that controls my hallway, which I’m not replacing with an Inovelli (for now :slight_smile:)

How can I wire my second Innovelli to my kitchen? What is the flagged wire? Is it the case that the line is in my triple gang box instead and I need to put the kitchen Innovelli in there? (I would much prefer both of them in the double gang if possible). And if that’s the case, could I use some wire connectors to use the same line in the double gang box for both Inovellis? (What would I do with the flagged wire?)

Please let me know if you need any more info/have any ideas. Thanks!

  • Do you have pictures from before you starting taking things apart/rewiring?

  • The two-gang box has switches for the kitchen (the problem) and the living room. I know you posted it but please confirm. Both of these switch legs are on the same breaker/circuit?

  • In the two-gang box when the kitchen (right position) dumb switch was wired, were the three conductors attached to the switch (excluding the bare ground) all from the same 3-wire Romex?

  • If the answer to the prior question is yes, which of the three conductors was connected to the black screw?

  1. I wrote down how they were wired before, and here’s how the kitchen switch was wired:

    The old switches were Lutron Divas with 3 wires coming out (Red, black, and red/white). Here’s lutrons wiring for them: https://assets.lutron.com/a/documents/368-4493_page_5.pdf

Here’s how they were wired:

Living Room Switch (Left Switch)

  • Red (lutron) to red (wall) (now the inovelli traveler)
  • Black (lutron) to black (wall) (now the inovelli line)
  • Red/White (lutron) to white (wall) (now the inovelli load)

Kitchen Switch (Right Switch)

  • Red (lutron) to red (wall) [right romex]
  • Black (lutron) to tagged black (wall) [middle romex]
  • Red/white (lutron) to untagged black (wall) [right romex]
  1. Correct, they are on the same circuit/breaker. In order to cut power to that box (and the 3 gang box fwiw, and all the loads), all I need to do is flip one switch on my breaker.

There are three romex’s coming into the box (Left, middle, and right). Maybe this picture shows it a little better. Up above I pointed out which romex’s the wires were originally connected to. They were not a part of a single romex, they were split across two.

  1. It was no. But making things more complicated is that the old lutron switch doesn’t have a black screw. It just has 3 wires coming out the back that you connect to the wall wires…

Thanks, that was worth a shot but I will try it another way. In the two gang box there are three roommates at the top. Working left to right they are a 3-wire a 2-wire and a 3-wire. Is that right?

If that is correct, for the 2-wire in the middle, if you disconnect the black conductor from any connections and then measure with a meter between that Black conductor and that white bundle, do you get a constant 120V, even flipping the dumb switches in the three gang box?

That is correct, it’s a 3 wire, then 2 wire, then 3 wire. I don’t have a multimeter on me at the moment, I’ll grab it and check that tomorrow after work.

Ok I just tested it.

Connecting the black wire from the middle romex (the flagged black wire in my images) to the white bundle (the neutral wires, right?), gives me 1.1V, no matter what the state of the dumb switches are.

Ok, so for the Inovelli in the 2-gang on the left that you say is working properly: Where are you getting the hot from that switch from? It doesn’t make any sense for that 2-wire to not be hot if that is the Line box.

Perhaps you can explain or diagram how you wired that one and got it to work with a dumb switch. When you say the switch on the left works properly, is that with it’s mate dumb switch in either position?

What is the black from the 2-wire in the two gang box connected to?

Sorry maybe I didn’t explain it super clearly at the start. Here’s a better explanation of how things are wired in the two gang box. The hot for the new inovelli switch is coming from the left romex, not the middle one.

Left Romex:
Red → Inovelli Traveller
Black → Inovelli Line
White → Inovelli Load

Middle Romex:
White → Inovelli Neutral
Black (Tagged) → ??? (Previously → Lutron Black wire)

Right Romex:
Red → ??? (Previously → Lutron Red wire)
Black → ??? (Previously → Lutron Red/White wire)
White → Inovelli Neutral

That is correct, the inovelli on the left currently works with the dumb switch in either position, exactly how I would expect.

The black from the 2 wire is currently not connected to anything (It was previously connected to the lutron black wire).

I’m going to suggest that you seek the help of an electrician to help you identify what you have going on. I’ll just say that I don’t think the Inovelli on the left is wired correctly. The presence of a hot and two travelers in a single 3-wire suggests a non-neutral topology or hot originating in the other switch box. You have grabbed a white from another conductor that you don’t know where it goes for the neutral. Just because it works doesn’t mean it’s correct, or safe.

Unfortunately, your pics don’t have sufficient resolution to allow zooming in to trace. I think you’ll have to do a lot of testing to fully understand where each of your Romex are going. If you don’t understand the topology, then wiring becomes an impossibility.

Regarding the switch you are trying to set up, if the hot keeps alternating between two conductors on a 3-wire, then the hot is originating in the other box.

Sorry, but there is only so much you can do here. You should probably get an electrician to help you figure out what is going where. If you can draw that out fully, then we can tell you how to adapt to the Inovelli.

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Got it. I was hoping it would be fairly straightforward, but I guess not. I’ll have an electrician come and do it and hopefully explain it a little since I’m very curious now. I really appreciate your time, thanks!

And thanks for pointing that out, I’ll put the old switch back in the way it was and let the electrician install them all.