reduced voltage at outlets, and ground test question

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Old 11-22-08, 10:39 AM
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reduced voltage at outlets, and ground test question

Can voltage in a run of outlets/lights be reduced to the point it lights a test lamp, but not enough to light a 4 watt bulb? Below is a description of my problem:

I have a run of three outlets (maybe other receptacles too) that ends with a ceiling light receptacle in the basement. The light stopped working, and my mom asked me to put a new light receptacle in. I did, but the light still did not work (bulb is good, fuse is good).

I saw an outlet that feeds the light receptacle, and tested for current at that outlet. My test lamp lit up when I inserted the prongs in to the hot and neutral slots. What was odd was my mom got a small candle light (with about a 4w type nightlite bulb in it) - and it would not glow! So it looks to me like there is just a trickle of voltage - enough to light the test lamp (which I guess has to be like a 1/10th of a watt), but not enough to light the higher 4 watt bulb (or the 100 W bulb in the light receptacle).

At least 3 outlets in front of that light receptacle also show this reduced voltage. What would cause this? How would I test?

The other thing I tested was the ground at the outlet that feeds the light receptacle (at the end of the line). I don't know if the receptacle is grounded properly, or has anything to do with the low voltage, but this is what I found.

When the low voltage was present at the outlet, my test light lit up when I put on probe in the hot slot and the other in the round ground slot(but not the other neutral slot, so I thought it was properly grounded). Then I pulled the off/on chain at the new light receptacle, and saw the outlets in front of it would not light my test lamp. Also, at the same time that these outlets did not show power on the test lamp - both the hot slot and the neutral slot tested like they were both grounded! Is that correct?

Is it possible that trying to turn on the light bulb at the light receptacle could "suck" the little voltage past the outlets in front of it to the point that they would not then be able to even light my test lamp?

I'm no genious with this stuff, so be gentle please. But I would appreciate any insight as to what may be wrond, and how I can test and correct this for my mom.

Thanks, Matt
 
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Old 11-22-08, 11:06 AM
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You need to start at the first receptacle that works correctly and redo the connections in that box. If any back stab connections they need to be moved to the screws. Screws need to be checked for tightness, and wire-nuts replaced. If that doesn't do it you need to move on to the first bad receptacle .
 
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Old 11-22-08, 04:05 PM
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Ray, thanks for the feedback.

I looked at the circuit more, and took apart the 1st outlet. I also have some additional observation and testing info.

First, I put a 3 prong ground tester into all 4 of the outlets, and the outlet on the new light bulb receptacle I just put up.

On the 4 regular outlets, the 3 prong ground tester indicated HOT - GROUND REVERSED.

On the outlet on the light bulb receptace it gave me 2 different indicators, based on me pulling the chain for the light bulb. In one chain pull position it says HOT - GROUND REVERSED, in the other pulled position it says OPEN NEUTRAL.

I also found that there are 2 other light boxes on this run. Neither of them were ever outfitted with a light appliance, they were just left with the wires twisted together in the steel box. I tested and found they were on the same circuit, in between the 4 regular outlets, and before the last light outlet I just replaced. What was strange was the test lamp did not glow when I touched the black/white wires in these 2 boxes. But thet test lamp did glow when I touched the black wire to the steel box, AND when I touched the white wire to the steel box. This can't be correct, can it?

I also noticed that 3 of the 4 regular outlets are upside down in the boxes, that is, the round ground slot is at the top, instead of below the HOT/NEUTRAL slots. These have been like that forever, so I assume that is not the reason for my new problem.

I did pull the 1st outlet out, and the wires are pushed in, not wrapped around the screws, so I am thinking that if I am going to take those apart, I might just as well get 4 new outlets also?

One thing I did notice on the outlet I pulled out, was that there were two cables, one coming in, the other going out. The black wires were pushed into the outlet, as were the white wires. But, the white wire locations did not seem to be in the same orientation as the black - by which I mean the input cable's black wire was in the upper push in, the output cable's black wire in the lower push in, but the input cable's white was in the lower push in (I expected it to be in the upper) and the output cable's white wire was in the upper push in. I don't know if that is ok or not, but it seemed odd to me.

Also the bare ground wire was twisted with a wire in the box, and then attached to a green ground screw in the outlet. It had a bit of a green tinge on it. Is that copper oxidizing? Is that ok?
 
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Old 11-22-08, 04:40 PM
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HOT - GROUND REVERSED
Which actually usually means an open neutral.
What was strange was the test lamp did not glow when I touched the black/white wires in these 2 boxes. But thet test lamp did glow when I touched the black wire to the steel box, AND when I touched the white wire to the steel box. This can't be correct, can it?
This would be caused by an open neutral.
I also noticed that 3 of the 4 regular outlets are upside down
No such thing. Either way is correct.
I did pull the 1st outlet out, and the wires are pushed in, not wrapped around the screws
These are the backstabs I wrote about in my first post. They are notorious for failing. Moving to screws should fix the problem. If you wish to change them out you can but moving the wires to the screws may fix it.
 
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Old 11-22-08, 06:31 PM
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It does not matter that the wire pairs are not across from each other either on the screws or in the backstabs.

As you have been told either replace the receptacles or move the wire connections to the screws. Make a clockwise loop and slip around the screws and tighten.
 
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Old 11-23-08, 11:52 AM
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ray2047, pcboss,

Thanks for the help. I will put the wires on the screws as you suggest.
 
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