3-way installation in box with unused neutrals

I’m working through installing a pack of blue and white switches throughout the house (early 2000s construction). The first couple of three-way setups were very by the book, but cracking open the switches in the master bedroom revealed a different setup.

This is another three-way setup getting one blue and one white switch. The first switch is in the bedroom next to the bed, the other is outside the door in the hallway. They control a pair of switched outlets that flank the bed.

The switch in the bedroom shares a box with the ceiling fan switch. The hallway switch shares a box with one of the hallway switches, which is on a separate circuit.

This is where it seems odd- both boxes have neutral wires in the back, and the other switches in there use them, but the switches I’m replacing don’t. Instead, each one has a single romex coming into the box. The white wire goes to the common, red to traveler, ground green, and black to load.

Should I tie the new switches into the neutral, or set them up as a non-neutral install?

It’s tough to see into your boxes, but I’ll give you my initial thoughts.

I am guessing that you have Romex and in each box, the three conductors connected to each switch are all from the same Romex. Is that correct? In other words a 3-wire Romex comes into the box and each of the three conductors (exclusive of the bare ground) is connected to a screw. There is not bundling with other wires in the box.

Based on what I’m seeing, my initial impression is that you have a power to the light with the power being sent over the white in the box with the dumb switch. The black electrical tape, presuming it was put there by an electrician, indicates that wire is hot. I’m guessing that is the hot feed from the light or it is a switched hot feed from the other switch.

If I am correct, this means you’ll have a non-neutral config for an Inovelli. You’ll then have to figure out which conductors make it over to the other box to send a hot and traveler for an Aux switch.

If you’re not comfortable with this situation, you should see the help of an electrician. A couple of points of information:

  • 3-way switches do not have an on or off, they have two positions. In one position, the black screw connect to one of the brass screws. In the other postion, the black screw connects to the other brass screw. So testing with a switch is “on” or “off” isn’t a thing.

  • Do not be tempted to use a neutral from the other switch legs in the box. The neutral for the switch leg your are wiring in in the light box, wired to the light as it should be.

I would start by testing the white wire with the black tape to see if it is constantly hot, WHEN IT IS REMOVED FROM THE SWITCH. Use a meter, and test between that conductor and a bare ground. If it’s not constantly hot, it may be a switched hot from the other switch. Figuring out which it is is crucial to determining where to place the Inovelli.

Thanks for the advice- I was able to get a little further, but rant into a few more wrinkles. I took it as a sign to call out the electrician and take care of the rest of my punch list at the same time. With the amount of time it took him to figure out what was going on with some of the wiring, I’m glad I didn’t try to figure it out on my own.