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Old 09-22-2010, 05:43 AM   #16
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Outlet before light switch; Open Neutral?


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Originally Posted by oberkc View Post
Well, then. This sounds like a good place to start tomorrow. Test the lines. Make sure you are getting voltages you should. Black to white should be 120VAC. Black to ground should be 120VAC. White to ground should be 0. If you get something different, then something is wrong.

Let's start here. It is hard to get your outlet correct if you supply is all messed up.
Sounds like a plan. Thanks for letting me know what I'm supposed to get for each placement of the probes.

I'm at work at the moment, but when I get home I'll grab my tablet and sketch out the diagrams too. I never get everything just as I like it in MsPaint.

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Originally Posted by joed View Post
OK I reread all the post. The bottom half of this image is what you need to end up with.
Well it's reassuring to know that the way I first wired it was indeed how it should be configured. I'll get the camera this afternoon to give a better idea of what I'm doing, and I'll try to document as much about the line voltages as I can. You guys are already helping, you shouldn't have to guess what's going on. (Well, apart from how the lights in the ceiling are wired. I have to guess at that too, since I can't get to them.)

Let me know if there is anything else I can do that might aid anyone in solving this problem.

Thanks again,
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Old 09-22-2010, 06:26 AM   #17
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Outlet before light switch; Open Neutral?


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Well, apart from how the lights in the ceiling are wired. I have to guess at that too, since I can't get to them
Actually, there are things one can to to confirm such things. You can remove the fixture and verify numbers of wires coming and going. You can measure voltages here. You can measure resistances.

Even if the fixture is not readily removeable, there are things you can do to verify at least some aspects of the wiring.

Guessing is rarely necessary.
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Old 09-22-2010, 04:29 PM   #18
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Outlet before light switch; Open Neutral?


I have news:

Code:
Source Wire test
B2W: 120
B2G: 120
W2G: 0
OK!

Switch Wire Test (Neutrals not connected)
SW is the white from the line in (Source)
SB is the black from the line coming in, (source) and going to the switch

LB is the black coming from the switch, going to the Light
LW is the white coming from the light back to the box

SB2SW: 0
SB2G:  120

LB2LW: 76.7
LB2G:  120

SB2LW: 76.7
LB2SW: 0

SW2G:  120
LW2G:  32

Switch Wire Test (Neutrals connected)

W2G or B2G: 120
Above are my notes when testing. I'd actually created a bunch of little images in a number of different wiring scenarios, but I don't think I need to upload them, as I assume those numbers are not the norm. I guess I shouldn't have chalked those strange numbers up to me screwing up.

Am I correct in assuming that somewhere amidst those 4 lights in the ceiling whoever wired them "done messed somethin' up"? Namely, somewhere a ground is touching a hot wire?

If such is the case, and I am unable to access anything but the light bulb (I've not yet figured out how to remove these fixtures without cutting into the drywall) how would I even go about figuring out which light is wired incorrectly? (To minimize drywall repairs afterwards)
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Old 09-22-2010, 07:46 PM   #19
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Outlet before light switch; Open Neutral?


Assuming that I am following your nomenclature, we can conclude one thing with near certainty: your wiring is not as you originally understood it to be. All these tests were conducted with the switch box completely opened and the wires exposed, not connected to any other wires (except as noted about "neutrals"), correct?

Check your recessed lights. Is there an inner part (onto which the socket is mounted) that can be removed from the housing (mine are this way). If so, you may be able to get to some of the wiring. I am also assuming you don't have access from above.

Another conclusion that I would reach is that whites are not necessarily neutrals. You have voltages on some of your whites relative to ground. I think we can quit calling these "neutrals".

If you have voltage coming from the wires leading to the fixture, this tends to suggest that there is a power supply to the fixture. Such a condition tends to support the switch leg theory.

Regarding the light fixture, there are a couple of things that come to mind. Did you perform these tests with the light bulb installed? If so, remove it and remeasure the voltages between the LWwhite/LBblack/ground. A light bulb has some resistance to it and can give some interesting readings at times. After removing the light bulbs, does the LB2LW reading go to zero? What happens to the 32V LW2G reading?

Other things we can do is measure resistances. Make sure that the power to the light is off and that there are no voltages anywhere. Make sure the light bulbs are all removed. By probing resistance between two points, there are certain conclusions one can make. Are there any whites (or blacks, for that matter) in the switchbox that have zero resistance relative to ground? Are there any wires of any color that exhibit zero resistance relative to any other conductor (not ground). Does installing light bulbs change any of those readings?

I don't think we can conclude anything is "messed up" quite yet. If a ground touched a hot, you would be tripping circuit breakers. Do you remember how all this was wired originally? If you stated this, I missed it.

My current working theory is that your LW and LB are a switch leg (as originally suggested by joed). I have no theory yet on the purpose of the SB and SW wires.
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Old 09-25-2010, 08:20 PM   #20
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Outlet before light switch; Open Neutral?


I'm a bit out of my depth at this point I believe. I'll have to do a bit more research on a "switch leg".

It was originally wired like a normal switch. Black in to switch, out to...the ceiling. I can't get there. White comes back and goes to the white from the source line.

I'll do a bit of testing without lights, and try resistances.
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Old 09-25-2010, 10:11 PM   #21
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Outlet before light switch; Open Neutral?


I am confused by your terms for the cables.
First you say the power from the source cable. That looks fine as power from the panel.
Then you talk about the source wire again and the voltages are messed up.

Label them cable 1, 2 & 3. Disconnect everything and measure the voltages between the wires of the cables.
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Last edited by joed; 09-25-2010 at 10:18 PM.
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Old 09-26-2010, 08:38 PM   #22
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Outlet before light switch; Open Neutral?


Sorry. Source meaning, coming from the circuit box. I'll get a diagram up before I go any further.

Straight in, before it hits the light, it's normal voltage. It's when I connect it to the switch that it gets all wonky. (Neutrals disconnected)
Though, from what I've come to understand, the white coming back from the lights probably isn't really a neutral line, or something.

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