Hi all.
I have a single hallway light that I decided to replace with two new fixtures. It is a 3-way with a switch in the office (3-way switch 2) and another in the hall (3-way switch 1). It appears that the source cable to the bathroom also pigtails from this box (switch 3).
Additionally, it appears that none of the switches are grounded…they don’t even have a ground screw. The house was built in 1979. Does this mean I need to update my switches? Plus, I keep trying to figure out how/why a black wire and a white wire are connected in switch 2’s box. Isn’t that black wire hot and that white wire neutral? I would have expected it to short out.
My plan is to pigtail a cable from the current fixture box to the new fixture box. My concern is the best way to get all of the wires properly connected. In my existing fixture box (which I will be replacing with a roomier box) I have my source cable, a cable to the bathroom, and a cable to switch 2. I will also need to add a 4th cable that goes to my new fixture box. So, should I combine all 4 wires (of each type) with the (5th) wire from the light fixture into one connector? If so, is there a wire nut that can safely accommodate this configuration? If not, what are my options? Existing cables have 14 gauge wires.
Lastly, I am installing the new light fixture in the ceiling of the first floor (so, no attic or crawl space access). There isn’t a stud conveniently located to attach the fixture box. Any suggestions on putting in a brace without having to dismantle the ceiling? I abhor drywalling. ; – P
Oh, one more thing…my terminology above is subject to my limited knowledge and may not be correct. Although I grew up helping my father with doubling the size of our house, I didn’t listen so good to what things are called. In doing research I have picked up some of the lingo, but keep having to google what things are referring to. I appreciate your patience.
Thanks in advance for any suggestions/answers/help.
Best Answer
Think of it this way. A pair of 3-way switches, together, acts like a simple switch.
So when one of the 3-ways is on a spur like that, it's pretty simple. The 2 travelers (brass screws) can be ignored, and treat it as 1 plain switch between the wires that are on the "common" (black) screws.
So that would be the white from the /2 cable, and the black from the /2 cable.
That is a classic switch loop.
I very strongly recommend using colored tape to re-mark wire colors so they match their function. In particular up in the lamp box, the black to the lamp and the black *from the switch are both switched-hot. I would strongly advise marking them with red tape.
As far as the white wire being as a hot in the switch loop, that's not an option, Code requires you to mark that black (well technically any hot color will do). So mark that black at both ends.
This makes it easy to see what is going on in your boxes. Hopefully it will then be obvious that your fourth cable should attach to white and blacks if you want the cable to be always-hot, or white and red if you want it switched with this light.
As far as braced junction boxes designed to be installed through the final hole into existing drywall, they make "old work" fan-rated boxes. If you put a lamp in a fan-rated boxes, I promise not to tell :)