I’ve (poorly) drawn a diagram and the voltage of each wire to ground in different switch combos. An additional complication is that there’s actually a THIRD switch in the second box that is part of ANOTHER three way, which hopefully can be ignored for the most part (I’ve labeled it as “3”).
Please note that I DO NOT know if B1 on switch 1 is actually the same as B1 on switch 2. Think of them as totally independent labels.
If anybody has any clue as to which setup this matches I’d really appreciate it. Please let me know if there’s any further info that’s needed…thanks in advance!
Please modify your drawing to reflect the position of the common black screw on each switch.
Then, in each box, remove the conductor attached to the black screws (probably a black conductor) and test for voltage between that disconnected conductor and the white neutral bundle or the ground. One of them will be hot and one will not have any voltage.
Do not test with the conductors connected. It does not matter the switch positions as you are testing with the conductor removed.
Double check your drawing for the connections to the single switch box. The common screw is typically positioned lower right on the two screw side (or at least lower if the drawing is flipped). I’d expect the black from the two wire and that box to be connected to the common screw but your drawing has it at the top right.
Thanks for your response. I’ve circled the black screws on both switches involved here. They are also labeled “common” on the back of the switches. The two are of different brands, so maybe that’s why they’re in different positions:
When disconnected (and with the power turned back on), the one on switch 1 (B1) shows 0 voltage to ground, and the one on switch 2 (B2) shows 120 voltage to ground.
From your drawing, you have a line and load in separate boxes. The line box is the 2-gang and the load box is the single switch.
The line is coming into the 2-gang box where it connects to the common screw of the switch and is jumpered to the unrelated switch to provide power for that switch leg.
At the load box, the 2-wire whose black is attached to the common screw is going to the light.
So to wire with a dumb switch, the Inovelli goes into the 2-gang box. Follow the line and load in separate boxes neutral installation diagram.
