Wiring a Light Fixture: Expert Edition
August 12, 2020 5:48 AM Subscribe
How do you hook up a basic light fixture when you have two light switches AND the original, non-grounded two-wire is being used from the breaker box? (Photo and disclaimers inside.)
Disclaimer: While my DIY skills are well-advanced, I know my limits in some areas, and I will be hiring a professional electrician for this job, but I won't be there when they do it, so I still really want to know the answer to this.
I took down an old light fixture but didn't take photos of the connections because I have installed dozens if not a hundred light fixtures and ceiling fans for myself and others over they years. But this is new to me:
In this photo, you see the expected four-wire Romex with red wires for light switches, like usual (all the yellow nuts). But you ALSO see the original two-wire power from the house (orange nuts). The two-wire is on when the breaker is turned back on (122.318 VAC, to be exact) regardless of light switch position, but I never get anything from the Romex even when the light switches are on/off, therefore obviously the three sets of wires all work together in some way.
But how? How do you know which is hot and which is neutral from the two-wire? Which wires connect with which wires? I think I know, but I am not going to guess, nor am I going to trust any YouTube videos on the subject.
Like I said, I am going to hire this one out, but I still really want to know because it's the first time I have had to hire-out a home-rehab project in over 20 years.
Disclaimer: While my DIY skills are well-advanced, I know my limits in some areas, and I will be hiring a professional electrician for this job, but I won't be there when they do it, so I still really want to know the answer to this.
I took down an old light fixture but didn't take photos of the connections because I have installed dozens if not a hundred light fixtures and ceiling fans for myself and others over they years. But this is new to me:
In this photo, you see the expected four-wire Romex with red wires for light switches, like usual (all the yellow nuts). But you ALSO see the original two-wire power from the house (orange nuts). The two-wire is on when the breaker is turned back on (122.318 VAC, to be exact) regardless of light switch position, but I never get anything from the Romex even when the light switches are on/off, therefore obviously the three sets of wires all work together in some way.
But how? How do you know which is hot and which is neutral from the two-wire? Which wires connect with which wires? I think I know, but I am not going to guess, nor am I going to trust any YouTube videos on the subject.
Like I said, I am going to hire this one out, but I still really want to know because it's the first time I have had to hire-out a home-rehab project in over 20 years.
You have three way switches, switching neutral. Hot's gonna hot, as expected. The red wires were most likely connected together as a "traveler" between the switches.
Check voltage on the neutral when the switches are up-up, up-down, down-up, and down-down.
...and on preview, look at the "fixture between switches" diagram linked above. You may even be incredibly lucky and find the wire colors are correct!
posted by notsnot at 6:36 AM on August 12, 2020
Check voltage on the neutral when the switches are up-up, up-down, down-up, and down-down.
...and on preview, look at the "fixture between switches" diagram linked above. You may even be incredibly lucky and find the wire colors are correct!
posted by notsnot at 6:36 AM on August 12, 2020
Best answer: Your situation isn't going to look exactly like the diagrams because you have all three cables coming to the same box. You have eight wires and when you add your fixture, you will have 10. Ten wires will need five wire nut connections in pairs.
First off you need to identify the traveler wires and the common wires at the three way switches. You will have to remove the switch plates to look. The pair of terminals on one end of the switch are the travelers and the single terminal on the other end is the common.
1. and 2. Once you have identified the traveler wire colors, connect them in pairs. The colors may or may not match and it doesn't matter which traveler connects to which. You can swap them back and forth.
3. Next connect your black hot wire from the two-wire to one of the commons going to the first switch. It doesn't matter which switch, as long as it goes to a common terminal.
4. Connect your neutral white from the two-wire to your white wire on the fixture.
5. Connect your black wire from the fixture to the common on the second switch.
Connect all the grounds and a pigtail to the ground screw on the metal box.
posted by JackFlash at 8:24 AM on August 12, 2020
First off you need to identify the traveler wires and the common wires at the three way switches. You will have to remove the switch plates to look. The pair of terminals on one end of the switch are the travelers and the single terminal on the other end is the common.
1. and 2. Once you have identified the traveler wire colors, connect them in pairs. The colors may or may not match and it doesn't matter which traveler connects to which. You can swap them back and forth.
3. Next connect your black hot wire from the two-wire to one of the commons going to the first switch. It doesn't matter which switch, as long as it goes to a common terminal.
4. Connect your neutral white from the two-wire to your white wire on the fixture.
5. Connect your black wire from the fixture to the common on the second switch.
Connect all the grounds and a pigtail to the ground screw on the metal box.
posted by JackFlash at 8:24 AM on August 12, 2020
Response by poster: Ah, thanks, JackFlash. I was wondering why my situation was different. I am familiar with three-way switches, but NOT the extra wires, which is why I panicked a bit. Your instructions are amazing, though I may still hire this one out.
I also have another light I was going to do, but it's in a can and the newer connections look nothing like what is in the can, so I may need to hire that one out, too.
Thanks!
posted by TinWhistle at 7:46 AM on August 13, 2020
I also have another light I was going to do, but it's in a can and the newer connections look nothing like what is in the can, so I may need to hire that one out, too.
Thanks!
posted by TinWhistle at 7:46 AM on August 13, 2020
This thread is closed to new comments.
In particular, look at the fixture between switches diagrams.
posted by bfranklin at 6:24 AM on August 12, 2020