View Full Version : Bedroom Light Fixture Went Out And I Thought I Knew How To Fix It
biigchiips
Feb 12, 2013, 09:01 PM
About 6 months ago I replaced the light in my bedroom with a nicer more modern looking fixture that I bought at home depot. Everything went smooth besides the fact that current was still flowing through the white wire even though I turned off the wall switch. Ask me how I found out… Anyway I got my multimeter out and asked my wife to go start playing with the circuit breaker.
Fast forward to now, the fixture no longer works. First I thought the culprit was the Philips CFL bulbs but when I installed them in my bathroom fixture they fired right up, nice and bright. I decided to play electrician once more. I discovered that:
- The white wire (I believe the positive/ hot) has power to it regardless of the wall switch being on or off, the only way to cut power is to flip circuit (9 in my case) off
- My multimeter reads the voltage only when I ground the black lead to the electrical box on which the fixture hangs.
- When I use the multimeter to read the voltage on the wall switch itself nothing comes up, in other words, it’s at 0 volts.
I'm beginning to think they wired the fixture strangely and it’s something I'm not used to and the only thing I need is a new wall switch or that my black wire shorted out behind the wall. Before I proceed any help would be appreciated.
hkstroud
Feb 12, 2013, 09:22 PM
Describe the wiring in the ceiling box and the switch box. Tell us the number of cables and the color of wires in each cable and connections.
ma0641
Feb 12, 2013, 09:27 PM
Sounds like a switch loop with power at the box. Where are you measuring the hot white? At the switch or ceiling box? The white should have black tape or marking. This is hot to switch. Black from switch goes to fixture black and neutral white to light fixture white.
biigchiips
Feb 12, 2013, 09:38 PM
1 metal ceiling box with two wires. One wire is White and One is Black. Same goes for the wall switch box.
With the basement circuit breaker switch (9) ON, I measure +/- 120 volts at the ceiling box when I put the red multimeter lead to the white wire (I suppose hot) and the black lead to the actual ceiling box. In other words, if the black multimeter lead is touching the black wire in the ceiling box it doesn't read any voltage, only when touching the actual ceiling box.
ma0641
Feb 12, 2013, 09:52 PM
1 metal ceiling box with two wires. One wire is White and One is Black. Same goes for the wall switch box.
With the basement circuit breaker switch (9) ON, I measure +/- 120 volts at the ceiling box when I put the red multimeter lead to the white wire (i suppose hot) and the black lead to the actual ceiling box. In other words, if the black multimeter lead is touching the black wire in the ceiling box it doesn't read any voltage, only when touching the actual ceiling box.
That's as expected, the box is grounded. For whatever reason they ran hot on white. They could have tapped off an outlet and ignored the colors. What about the switch wires? None at the box?To have the light function you need a neutral at the light.
biigchiips
Feb 12, 2013, 10:45 PM
When you say switch, are you referring to the wall (on/ off) switch? If so, same story, on the right hand side of the switch I have (1) white wire and (1) black wire. I believe its 15 amp if that's any help.
hkstroud
Feb 12, 2013, 10:47 PM
1 metal ceiling box with two wires. One wire is White and One is Black. Same goes for the wall switch box.
If I understand correctly you are saying that you have one cable in the ceiling box with a black and a white wire. Also you are saying that you have one cable in the switch box with a black and a white. That is not logical.
You must either have two cables in the ceiling box, each with a black and white wire and one cable, with a black and white wire, in the switch box.
Or, you must have two cables in the switch box, each with a black and white wire and one cable, with a black wire, in the ceiling box.
biigchiips
Feb 12, 2013, 10:59 PM
If I understand correctly you are saying that you have one cable in the ceiling box with a black and a white wire. Also you are saying that you have one cable in the switch box with a black and a white. That is not logical.
You must either have two cables in the ceiling box, each with a black and white wire and one cable, with a black and white wire, in the switch box.
Or, you must have two cables in the switch box, each with a black and white wire and one cable, with a black wire, in the ceiling box.
The ceiling box has two (2) wires total. One (1) White wire which I've identified as the hot wire and one (1) black wire.
The wall switch box also has two (2) wires. One (1) White wire and one (1) black wire.
hkstroud
Feb 12, 2013, 11:28 PM
The only way that is possible is if previously there was no ceiling fixture and an outlet was switched. Later someone installed the ceiling fixture by running a cable from the switched outlet to the ceiling. In doing so they errored in the wiring.
Suggest you pull the outlets and correct the wiring.
ma0641
Feb 13, 2013, 07:02 PM
The ceiling box has two (2) wires total. One (1) White wire which I've identified as the hot wire and one (1) black wire.
The wall switch box also has two (2) wires. One (1) White wire and one (1) black wire.
A white and black at the switch would indicate a switch loop. To what we don't know. Check for a switched outlet that has a wire that feeds the ceiling. Is this box different in appearance from others?
DollhouseDoc
Feb 14, 2013, 01:12 PM
I have encountered switches and fixtures that are in series with an outlet (creative wiring!). Turn off the breaker and touch the two wires in the fixture box together, then test for continuity between the two wires in the switch box. I'll bet you find no continuity, but if you go to a nearby outlet that's turned off by the same breaker you'll find the two ends of the circle (I can't bring myself to call it a circuit).
This may be electrically sound but it isn't wiring sound, nor is it safe for future electricians (as you fond out), and it is bad practice. If you can't bring yourself to re-wire this at least put an explanation in all the boxes.
Find out how it's wired and draw a picture. That will help you clarify what is going on.
biigchiips
Feb 14, 2013, 08:43 PM
Firstly, I greatly appreciate your suggestions!
I think you guys are correct in that the ceiling box was an afterthought, perhaps installed in a renovation that the previous owner(s) did. What substantiates this idea is that the drywall is also patchy there (not seen once the lighting fixture is installed.)
I also think you guys are correct in that the wiring may have been tapped off an outlet. I'll check to see if all the outlets in the room are functioning and I'll unscrew a few wall plates of those outlets affected by circuit breaker 9 and check the wiring.
Ill also check for continuity in the switch box like DollhouseDoc suggested.
Thanks again!
DollhouseDoc
Feb 15, 2013, 08:15 AM
The way this scienerio usually happens is that two wires from an outlet go to a hub box. From the hub box, two wires go to the switch box. Also from the hub box, two wires go to the fixture box. In the hub box, the wires are nutted together in a circle so they are all in series. This happens often when remodeling moves a fixture and they just go from the old fixture box to the new fixture box and cover over the old box.
Two problems with this: It is hard for someone servicing the installation to know what is happening, and, if the hub box is covered over with wallboard, when the resistance in the nutted connections starts to go up (inevitable in the fullness of time), it isn't serviceable. This configuration is not why a hidden box is always 'not-to-code', but it is still a bad idea.
If you can surmise where the hub box is, you might put an exposed cover over it so it is accessible and then label everything in all of the boxes. It still ain't kosher, but at least it'll be safe.