Box] I have a light fixture above a stairwell. There are two live switches that control it, one at the bottom of the stairs, one at the top. The wiring is relatively new about 25 years old (all copper, no knob and tube).
I removed the existing light fixture, which functioned well, with the intention to install a new fixture. I forgot to make notes on how the existing one was connected to the ceiling box. There are two black, two white wires, and one bare copper ground wire. One black wire is always live, it seems to be independent of the two switches. The other black wire and the two white wires are not live, independent of the two switches. I have a multimeter to measure the current.
I am confused as to how I am supposed to connect the new light fixture. Please help!
Best Answer
Ok first you're going to have to take the cover plates off the two switches and take photos.
Chances are two of those wires are meant to be hooked together as the "traveler" between switches. Or, perhaps, that one hot wire is power feed to this setup, you need send hot down some line (maybe the other black) for the circuit to work. In that case one of the whites is neutral, the other is switched hot to the bulb.
You can see a bunch of wiring options for 3 way switches at https://www.easy-do-it-yourself-home-improvements.com/3-way-switch-wiring-diagram.html
Next time, take photo before!