ground and neutral reversed after light fixture install

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Old 04-10-15, 03:28 PM
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ground and neutral reversed after light fixture install

In my closet I had a simple light socket base with two terminals (no ground). I installed a new light fixture today. I took off the existing light socket base and in there are 3 white wires nutted together from the house with one white wire stripped in the middle and wrapped around one terminal of the base. The other terminal on the base has a single red wire connected. No ground wire is connected to the base and they appear to be bundled up in the rear of the electrical box.

My new light fixture is a dual bulb with two whites and two blacks and a ground.

I cut back the one white wire so it was no longer stripped in the middle and then wire nutted the three white wires from the house and two white wires from the new fixture. I wire nutted the red wire from the house and the two black wires from the fixture. I connected the ground wire from the fixture to the steel bracket that I attached to the electrical box.

The light turns on but a nearby plug now doesn't work and the plug-in tester I have says hot and ground reversed.

Where did I screw up? My first thought is that I need to open the fixture back up and attach the ground bundle from the house wiring to the same metal bracket the light fixture ground is connected to.
 
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Old 04-10-15, 04:10 PM
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The light turns on but a nearby plug now doesn't work and the plug-in tester I have says hot and ground reversed.
Why I really don't like those. They should carry a warning, "Results may be wrong". In this case it is telling you you have an open neutral not a hot ground reverse. Redo your neutral connection at the light.

For real testing you need an analog (not digital) multimeter,
 
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Old 04-10-15, 04:12 PM
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The tester showing "hot/ground reversed" often means the neutral connection has been lost. Open up the fixture and check ALL the neutral connections.
 
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Old 04-10-15, 04:18 PM
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Did they switch the neutral leg instead of the hot lead, for the light? That might explain the reading.
 
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Old 04-10-15, 04:48 PM
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Yep that was it. I knew it was wrong not to connect to the house ground, was just thrown off cause the previous fixture didn't connect to ground. Learn something everyday.

EDIT: Sorry I didn't know y'all replied. The problem was what I initially thought, the new fixture needed to connect to the house ground

I agree, those plug testers are sometimes wrong. I only used it really to see if any energy was getting to the plug. It came in the kit with my multimeter.

THANKS ALL!
 
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Old 04-10-15, 05:03 PM
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Glad you got it. I hope the multimeter wasn't digital. If it was maybe you can take the kit back and get what you really need, an $8-$15 analog multimeter..
 
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Old 04-10-15, 05:19 PM
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Yeah, I mainly got the kit because it had a test probe with it, which I really like. Just an easy way to make sure power is off in a box before working in it. Meter is digital. Curious why you prefer analog? False readings? I am proficient in reading the meter and testing some basic things like voltage and resistance/blown circuits, but diagnosing mis-wired circuits etc.with a meter Is beyond my knowledge and something I'd call my electrician friends to help me with. I wouldn't know in which order or wires to connect to in order to rule one scenario out over another. Thanks for the help
 
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Old 04-10-15, 05:42 PM
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Yeah, I mainly got the kit because it had a test probe with it, which I really like.
They're okay for a quick voltage test but they can't be used for testing because they too often give false readings. Can't count the number of people posting here because they were relying on one and the false readings were causing them to fail at solving the problem.
Curious why you prefer analog? False readings?
Yes. Because of their high impedance they will show capacitive charges and induced voltages which really are not true readings. There are some very expensive digital meters ($100+) that have special circuits that recognize false readings and reject them. Of course if your aware of their limitations and when to ignore a reading they are okay. But in the DIY world a analog multimeter whose low impedance usually "drains off" induced and capacitive voltages is best.
I wouldn't know in which order or wires to connect to in order to rule one scenario out over another.
Measure neutral (wide slot) to ground. If you get ~120 volts it is reversed hot/neutral. No voltage wide slot to narrow slot but ~120v to ground is open neutral. No voltage ground to narrow slot is an open ground..
 

Last edited by ray2047; 04-10-15 at 05:57 PM.
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Old 04-10-15, 06:26 PM
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The ground plays no part in the normal operations of a fixture. It is only there in the event of a fault.
 
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