Only one of two lights work; one switch


Old 12-01-06, 08:06 PM
Thread Starter
Join Date: Dec 2006
Posts: 3
Only one of two lights work; one switch

I had a bulb on one light inoperable unless I wiggled it (there are two lights operated by one switch) so replaced fixture -attached black wire to brass screw, white to silver screw, red to green screw. There is no green wire. There are a white and black wire nutted together. The bad light now works fine, but the other light now won't operate at all. It has a white and red wire, with three black wires nutted together. I attached white to silver screw and red to green screw. Also tried different arrangements, including putting one black wire on the brass screw. That resulted in a reversal, the formerly good light worked again, but the originally bad light stopped working again. How do I get both working together again from the wall switch?
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Old 12-01-06, 08:17 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
You did something extremely stupid. Before you kill yourself, turn off the circuit breaker. You are lucky to still be alive.

You should have connected the new fixture in an identical manner to the old fixture.

Green screws, green wires, and/or bare wires are for ground wires only. Connecting a red wire to the green screw could very well be putting 120 volts on the frame of the light.

Put both light fixtures back the way they originally were. Then connect the two wires (plus perhaps a ground) that are connected to the fixcture you want to replace to the new fixture.

In the event that you cannot remember how things were originally connected, you will have to supply a detailed description of ALL the wiring at each light and at the switch. And by all the wiring I mean just that all the wiring. Each cable, and each wire in each cable.
Old 12-01-06, 08:29 PM
Thread Starter
Join Date: Dec 2006
Posts: 3
New fixture doesn't match

The old fixture had two brass screws and two silver screws, no green screw. I marked which wire went where, but could not find an identical fixture. The original is about 20 years old. The new fixture only had brass, silver and green screws. If the green screw is the ground, which wire goes to it if there is no green wire? Is it time to call an electrician?
Old 12-01-06, 08:42 PM
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
Calling an electrician is never a bad idea, but if you've got the patience it's not too tough to figure out. Once you figure out which cable is going where, you can just connect the dots to see how it works.

Google "switch loop" which should explain why the white & black wires are nutted together.

Turn off the breaker.

Describe the cables (or conduits) coming into each box:

For each box, number your cables and list the wires, by color, in each cable.

For each box, list which wire in each cable is connected to which other wires in other cables.

Open your switch box and make sure it's got a black and a white wire only.
Old 12-01-06, 09:01 PM
Thread Starter
Join Date: Dec 2006
Posts: 3
More detail

The original light had a white cable with: 10 a bare wire that was coiled into the receptacle, not connected to anything; 2) a white wire that led to a wire nut; 3) a black wire that led to one of two brass screws.

It also had a black cable with: 1) A black wire nutted together with the white mentioned above; 2) a red wire that led to the second brass screw; and 3) a white that led to one of two silver screws. The second silver screw had nothing attached to it.

I'm having trouble seeing the second ceiling light. It appears to have two white cables and one black cable. There appear to be 3 bare wires nutted together, 3 white wires nutted together, and 3 black wires nutted together. There is a red wire presently attached to a green screw and a white wire attached to a silver screw. Nothing is attached to the brass screw. This is the new fixture. The old one had two silver and two brass screws, but I didn't mark where the red wire went and where the white wire went.
Old 12-01-06, 09:41 PM
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
You didn't say if you checked the switch. I am assuming it is a switch loop. You also mention "original" light and I am assuming that is the box at which you replaced the light fixture.

Replaced fixture cables:
W/B cable goes to switch: 1W and 1B
W/B/R cable goes to other light fixture box: 2W, 2B, 2R

Other fixture cables:
W/B/R cable comes from replaced fixture box: 3W, 3B, 3R
W/B cable comes from panel: 4W, 4B
W/B cable goes to next box in daisy chain: 5W, 5B

Based on the info presented, I can't tell which cable is 4 and which is 5, but that shouldn't matter since it's a daisy chain.

Now here's what you need to do. Somebody please check my work.
Wire nut connections:
1W + 2B
1B + 2R + Fixture brass screw
2W + Fixture silver screw

3W+4W+5W+Fixture silver screw
3R + Fixture brass screw

I'd post a diagram but I'm beat. Plus, I'm lazy. I'll check in in the morning. Good night.

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