3-way wiring - blew my switches; need a 2nd pair of eyes

sudhikan · February 24, 2026, 7:27am

Hi all -

I recently got a 5 pack of the VTM31-SN. I installed two of them in a single pole configuration and it worked well! But I had two that were in 3-way configuration and I had a bad experience with them.

See my wiring diagram below to help with the narrative…

I initially wired up sw1 with the guts of the gang box exposed. I just wanted to make sure the wiring worked. It did work and I was able to validate the setup both in the Inovelli switch as well as the dumb switch I paired with it. Of course because the dumb switch worked, means I was able to configure the Inovelli switch by pressing the down button and hitting the config button 5 times.

Seeing success, I wired up the second one in the gang the same way, the gang box was tight so I had to push things in a bit and then I finally closed it.

I turned the breaker on; the second Inovelli switch also came up. I went to configure it in a 3-way setup with a dumb switch, and the moment I got the confirmation LED light, I heard a small hissing sound followed by burning smell.

Immediately tripped the breaker off.

I pulled out the bad switch out (sw2), with the wires exposed, I turned on the breaker again and I tried toggling the other switch (sw1), and within seconds even that made a hissing sound and went out.

At this point, I reverted the config back to two dumb switches …

Below are my wiring diagrams of what I did.

I want to get confirmation that the wiring diagram is correct?

If it is, then I am blaming the fact that I jammed all those cables in and maybe caused some short somewhere.

Any feedback would be much appreciated.

Gang box 2 is very clean; it only has 2 Romex cables coming in and nothing else. Of course there is no hot here. but curious if there was any way I could put the Inovelli in the 2nd gang box with more space?

sudhikan · February 24, 2026, 7:38am

I should also say that I used gemini pro to get the wiring diagram. Second time AI caused me to lose $$.

I just spent some time reading through the forums and I think it’s highly plausible that I can do [scenario 1] . In this case, I just need to add a neutral leg to the Inovelli switch and the rest of the wiring literally stays the same.

Right?

Bry · February 24, 2026, 12:40pm

From what I can discern from your drawings, you have a Line and Load in the same box. If that is truly the case, the the INOVELLI drawing you posted above would be the proper one. For future reference, all Inovelli wiring diagrams (and a whole bunch more of stuff you need) can be found on their help site at https://help.inovelli.com . The wiring diagrams for the white dimmer are at:

I see errors in the wiring diagrams you drew, but I don’t know what liberties you took in drawing them. If you want someone to evaluate a wiring diagram, it should be drawn as if you are looking at the back of the switch, so that terminals in the drawing are in the proper positions.

So I would not rely upon your drawing or the current installation. Double-check the wiring based upon the Inovelli wiring diagram.

For clarity, if you have a Line and Load in the same box, this is the proper diagram:

As always, if you feel that you need assistance or don’t fully understand or are not comfortable with electrical wiring, it’s best to consult with a licensed electrician.