Home wiring: is 47V between neutral and ground OK?

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Hi All,
I just installed a ceiling light in my kitchen, and now I measure a 47V (AC) difference between the light's ground wire and its neutral wire. Is this normal, or could the ground wire be floating?
Thank you,
-Bill
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Bill wrote:

No, that is certainly not normal. Check the neutral and ground connections in the panel, as well as anything that uses those horrible spring loaded push-in terminals, those are notorious for developing bad connections, IMO they ought to be banned.
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James Sweet wrote:

I concur. Work your way back from the fixture with a voltmeter and see where you lose that 47V.
Story about spring loaded terminals: I helped a friend diagnose a flickering lights problem at his house. It seems that one circuit, heavily loaded was fed through a receptacle using these spring loaded contacts (in one set and out the other). It was the first device on the branch circuit and was easy to diagnose. Although nothing was plugged into it, the device was hot (thermally)!
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I just had a circuit go dead in my house the other night, tracked it down to the very same problem. I decided that while I'd already messed up all the clocks finding the right breaker, I'd use that opportunity to shut things down and replace the last few of the original upstairs receptacles I hadn't gotten to yet and in that process I found one more blackened corroded wire that had been arcing and was a failure or fire waiting to happen.
The contact area is simply too small, it heats up and then the spring loses tension and it starts to arc and heat up more. These things are a safety nightmare, I will never understand why the NEC is so nitpicky about some things yet lets major issues like these slide right by. Spend a few bucks more for decent receptacles, it's cheap insurance and peace of mind, not to mention plugs won't start falling out in a few years.
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James Sweet wrote:

I'm not sure if these things are still available. All I've seen at the local Home Despot are screw terminal types. Either the basic 'wrap the wire around the screw' or the 'stick the straight wire in the hole and apply pressure via an internal screw and clamp'. None depending on a spring alone.
Besides that, I don't like using receptacles for a feed-thru. Pigtails wherever possible, unless the box is too small to contain the extra wires and nuts.
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James Sweet wrote:

The problem isn't the NEC. The problem is UL allows these atrocities. At least the hole isn't big enough for #12 wire anymore.
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bud--

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bud-- wrote:

In Tallahassee a few years ago a local insurance agent had several unexplained electrical fires in his office suite. Photos in the paper showed an electrical outlet with the wall above it burned as if the romex cable had burned. He hired an EE professor from FSU who postulated that EM waves from a nearby cellular tower were concentrating energy into his office! I think more likely he had those backstabbed outlets and the office workers were plugging an electric heater into the outlets.
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Joe Leikhim K4SAT
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RFI-EMI-GUY wrote:

I've seen nearly this exact scenario, only the wire lost contact and opened the circuit before it got that far and it wasn't a heater, it was just several computers. EM waves from a cellular tower? That's ludicrous!
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James Sweet wrote:

Does any device use push ins for ground? I have not seen any (that doesn't mean they don't exist, I'm asking an honest question)
nate
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replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
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Nate Nagel wrote:

No, but they do for neutral, and if neutral is floating at all above ground, you'll measure a voltage between them. Of course the light will be dim in that case too.
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Bill wrote:

If you are using a digital voltmeter, you could be seeing an open circuit on the ground wire at the fixture. However, that being said, if you have an open neutral at the breaker box or service entrance, you have a serious condition warranting that you call for the utility service or an electrician immediately. Fire and death by electrocution are possibilities. Do any appliances or lights behave as the voltage is too high or too low? If so, you have a serious problem.
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If the fixture is working then leave it alone. If the fixture is not working remove it and hook up a rubber pigtail socket and bulb to the ceiling wiring to check it. Stop using your voltmeter. I'm guessing that you are checking the voltage between the neutral with the fixture lit and the grounding conductor.
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wrote:

*Granted. However the OP has failed to post any details. He didn't say if the fixture was working correctly or not. He didn't say how he came to find the voltage discrepancy. He didn't say why he changed the light fixture. I just made some assumptions that everything was working fine and he was just playing around with his volt meter. If the OP cares to furnish more details then perhaps my response will be different
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snipped-for-privacy@sbcglobal.net says...

Exactly right. I might note that a high impedance voltmeter isn't a good tool here.

That's what GFCIs are for. Place a GFCI upstream of these outlets and all is well. Place stickers on the ungrounded outlets marking them as ungrounded and you're even in compliance. Often, adding the grounded conductor just isn't practical.
--
Keith

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not connected together. If they are properly connected together in the entrance panel and the fixture is working, the ground is disconnected somewhere (floating). Use a bulb in a pigtail socket to check this. It should light from hot to neutral and from hot to ground. Be careful as a floating ground can cause dangerous voltages to appear on supposedly grounded metal parts, especially if you connect a load from hot to the ground.
Don Young
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Don Young wrote:

Worst case is that the test light will illuminate connected from hot to neutral. But it will be dim due to high voltage drop and the person doing the test will not notice. A high resistance connection will get HOT under load and may create a fire hazard. If a hot or neutral is wide open, nothing works, but nothing gets hot.
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First if you are using a modern digital meter, it may be giving false reading because it is very sensitive. In addition you may be getting odd readings because you are effectively measuring the load on the circuit. Try removing the lamp and use an analog meter and see that happens.
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Hi guys,
Many of you hit the nail right on the head: The ground is, for some reason, floating. I will hire an electrical contractor to look into this dangerous situation (I have found other wiring idiocies in this house, so I'll have him check everything for safety).
Thanks again!
-Bill
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well, you can fix this yourself if it is just a loose connection. Find the circuit affected at the breaker panel. Identify the cable connected to that circuit and check to make sure that both the neutral and ground wires are securely connected to the neutral/ground bus in the panel and that the screws are tight. (cut the breaker off before you mess with the neutral; if there's a load on there you may get a spark, and you don't want to flinch and hit something hot.) If you're not 100% confident in your skills skip this step and call an electrician because there is stuff in that panel that is always hot and I don't want to read about you electrocuting yourself.
What you can also do is cut the breaker off and find out what lights and receptacles are on that circuit (no longer work.) Then after you have those all identified and tagged, start testing each one with an incandescent test light, H-N and H-G. Should light both ways, as you already know. If it does not at ALL devices your problem is likely at the panel. If it does on some but not others, check in the area of where it stops working (last device that works/first device that does not) you may not know exactly how the circuit is run so you may have to open up a couple boxes. Make sure that at every box all grounds that enter and leave the box are spliced together, bonded to the box, and connected to the green ground screw on the device (if present.) If you think you've found the problem, fix what you've found, cut the power back on, test again. Hopefully this will help.
good luck,
Nate
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Bill wrote:

Welcome to the joys of owning an older home. You never know what surprises are lurking, keeps life interesting.
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