1d ago

Odd wiring in a 2-gang

I am installing smart switches in my home. I have this 2-gang box at the top of our stairs, where I am doing a virtual 3-way setup for both switches. One powers the light on the stairs, the other the hallway at the top of the stairs. A few things:

This box has no live wires since its the other side of the two 3-ways (I have tested this by disconnecting all wires from all switches and checking for lives).
Each of the boxes is on a separate breaker. It has TWO sets of neutral pigtails in the back. This is the correct setup, but its possible the neutrals where mixed up during the original wiring of the house.
Each set of romex wires is connected to another set of romex. None of them criss-cross (except the grounds).

Now, here is my odd behavior and my need for assistance:

After wiring the two virtual 3-way setups (Option 2 from this page) everything was working fine. I was also planning to switch out the fixtures, so I went back and turned off the breaker for the hallway, but the smart switch for the hallway was still active (LED is on, I can see it on homeassistant). Now, I am thinking the original wiring mixed up the loads in the box with the incoming wires and the two neutrals for those breakers have been connected...anyone have thoughts on whats going on? is the solution here to basically swap the incoming 3-wire load romex?

**Solution: ** I am not 100% certain the cause of the issue. It is possible I mixed the wiring up when doing the virtual 3-way, but I basically followed the advice here and started from scratch. I traced the travelers from each of the main boxes and connected them to the appropriate load and completed disconnected the 3-way part. once I had the right load on the right travelers, I then setup the virtual switches wiring off the black wire coming with the traveler. Lastly, I ensured the neutrals from the two romexs that had a traveler+load where pigtailed with the virtual switch. took a bit of time, but felt this was the easiest way to not spin my wheels too much. Appreciate the advice, if anyone really does want, I can put together a diagram (on paper 😉 )

10 comments

That option 2 wiring would be wrong for a dumb switch, so they’re relying on smartswitch behavior. I didn’t read too far into it but
they specify only certain models for the virtual switch. Are you using one of those?
those switches can also pair directly with smart bulbs: was the old fixture using those?
the writing diagram assumes three colored wires on the traveler (black, white, red) however older wiring commonly used only two. Can you verify you have three? With older two wire setup, the neutral was repurposed to traveller, making it easier to screw up
could you have lost some configuration on the switches when the power was disconnected?
It's a little hard to imagine without a diagram like the other poster mentioned. But what might be happening is that the 'travellers' (What you were calling the two neutrals) feeding each switch may have been mixed up. Try swapping two of them, or if you're confident using a meter check that the two travellers for each switch are attached to the corresponding switch on the other side
- Ok, so travelers in a virtual 3 way are non-existant really. They are repurposed as the load wire in a single-way. Basically: virtual 3-way eliminates the 3-way setup, instead having the 2nd switch simply communicate that it was pressed to the main smart switch. If you peek at the link I posted in OP, you can see a diagram of the wiring (obviously in the correct state).
  I am confident with a multimeter, are you recommending a continuity test? I could tie the load & traveler together, unless there is some other way to test which traveler corresponds to which main switch?
  
  It's been a few years since I worked in the field so the virtual three-way is a little bit more advanced than I'm used to. But yes I was suggesting a continuity test. One way to do it is that if the boxes are grounded you can test continuity to ground by touching the wire to the box on one side, and then using a meter check to see which wire has continuity to ground on the other side. Power off both circuits before grounding any conductors
Take a contactless voltage detector (or multimeter) to the hot and neutral of the fixture. When the breaker is on, is it 120v? What about when the breaker is off? If its something in between then you might be dealing with mixed hot and neutrals from different branches (sketchy)
I'm struggling to visualize this. Can you make a diagram of what you have verified?
- Do you have a recommended software for diagrams? hopefully something quick n' easy to use. I can provide a picture, but only one switch is clear unfortunately.
  
  Even hand drawing it on paper would help. You've got some weird stuff going on and it's hard to know what is vs what should be. It's also hard to translate terms like "hallway" into being box 1 or 2.
  
  No need for complex software. Paper+pens+camera is good enough. I would recommend MS Paint, but Lemmy users will quickly point out the existence of GIMP.
  Edit: it has been my experience that drawing out the circuit has helped me debug home wiring issues.
Now, I am thinking the original wiring mixed up the loads in the box with the incoming wires and the two neutrals for those breakers have been connected...anyone have thoughts on whats going on?
In order to understand what was going on: put back the original wiring. 100%. Then take your meter and find out why and how it was working.
If the original wiring was working, but still has confused you, then your description for us is bound to be confusing as well, and then we can never know what was reality before (unless we have a very experienced teacher here who has seen it all and knows your confusion in all detail)

10 comments