Puzzle - two light switches


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Old 06-01-14, 05:46 PM
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Puzzle - two light switches

I am generally competent with electrical circuits and wiring. I have wired homes. I reference wiring diagrams, etc. So, I am not a total newbie. Not an electrician, but pretty knowledgeable.

I have an old farmhouse. Need I say more? All that said, YEARS ago a light quit working. It was a junky florescent that was poorly installed (flush mounted against a drop ceiling). We do not use the room much. I finally got around to messing with it. I hated to drop the large fixture, so I decided to do the switch.

The physical switch has two switches, each single pole. As far as I know, these are the only things on the breaker; I have never found anything else. The one toggle works fine. To be clear, I turn off power at the breaker before making a change. I see that the power to the secondary switch/fixture turns off and consider it safe. This is done for each change mentioned below.

Step 1: I bought another switch and wired it identically. No change.

Step 2: Time to pull down the fixture. I attempted to pull it down normally. It did not go so well. The fixture was quite heavy and as I removed the last supprt screw, it came down faster than I thought. I did not have a chance to examine the wiring as it pulled apart on its own.

I looked at the wire nuts. One was missing (A) and I could not find it on the floor. It was a bundle of several wires without a wirenut. Hmm. I do not know of anything else running on the circuit, remember.

Two other older wirenuts were there. One was on a single wire by itself (C). Another had three wires (B). Hmm.

I should have tested at this point, but I did not. I guessed. I hooked up the fixture to wirenut A and C. No dice.

Step 3: Time to pull out the meter. I have a DVM. I put a jumper on the wire at the fixture and run that jumper down to where I can touch the switch leads.

Wirenut A did not show continuity anywhere at the switch. Wirenut B seemed to flicker all over the place. I assumed my jumper wire was not connecting well. Dumb assumption, but I made it. I tested wire C. It had continuity.

I attached to B and C. Turn on power.
The puzzle:

The light did not turn on. Then, I turned on the second switch and both illuminated. Hmm. I killed the breaker so I could think but left both switches on. Both lights FLICKERED continually. Yes, the breaker is off. Both are flickering. I separate my wirenuts and the secondary switch works fine.
HELP!

I hope you are following what I have said. I do not understand the wiring, and now feel like I need to take additional precautions so I do not get electrocuted (kill main for testing). Why the heck is there power on the circuit with the breaker off?
 
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Old 06-01-14, 06:04 PM
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Welcome to the forums! It would certainly help us if you could post a picture or two of the wiring in the ceiling and at the switches, with the switches pulled from their box, power off, of course. http://www.doityourself.com/forum/el...your-post.html
 
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Old 06-01-14, 06:21 PM
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It was a junky florescent that was poorly installed (flush mounted against a drop ceiling)
Normally when you want to service a fluorescent fixture you remove the lens first and then the wiring cover.

Pictures would definitely help because I can't follow it either.
 
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Old 06-02-14, 05:50 AM
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PJMax -- I agree. Normally a fluorescent would be mounted within the grid of a drop ceiling, not flush mounted to the surface. Normally, the wires are accessible within a metal junction box. Not here. A hole was drilled in the fixture and the wires fed through the hole. This mess is the reason I have left it alone for so long.

It occurred to me that I might have screwed up regarding which wire was the line (power). I do not know how. I recall reading the labels on the switch first. But it is possible, and would explain why the second switch must be on for the first to work. But it does not explain anything else.

I also failed to mention that the wire in the fixture is much more vintage than that at the switch. The feed from the breaker is vintage. Wires are not accessible from anywhere without tearing apart the walls and ceiling.

Thanks for the help.
 
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Old 06-02-14, 04:56 PM
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loose ends

the switch u have is for two seperate lights. the side on the pic is for switch legs. (wire to fixture only) , other side is for power. It will have 2 screws tied together. Can u figure out which wire goes where? How many loose wires at each device? Call a bk and white together as one cable. With power off short bk/wt in same cable and ohm other ends. Later make sure no wires touch , turn pwer on to find hot/neutral. I can walk u thru puting it back together then . Find what other switch feeds, could be receptacle or even nothing.
 
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Old 06-02-14, 05:31 PM
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turn power on to find hot/neutral.
There is no neutral there.

You are looking at home handyman 14-3 wire. Complete disregard for any logical color connections. The power is coming in on white (black is unused) and it's leaving the switches on white and black.

There is another splice box somewhere. That NM (romex) cable doesn't appear at the ceiling box.
 
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Old 06-03-14, 05:45 AM
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PJMax, you are right. It is totally messed up and not standard. That was what I was trying to explain. I can figure out normal wiring.

You are right about the junction box. I attempted to explain that when mentioning the vintage wiring vs romex. I even speculate that it might not be in a junction.

I will start by separating each wire and connecting a toner. Perhaps I can find which one is the line by putting the tone generator by the breaker, and then go from there.
 
 

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