Bad GFI?

sckeeth

Got a call from a customer that said they have an electrical problem. they stated that there ups smelled like it was burning so he took it outside and disconnected the battery. He goes back inside and notices that the hall light is really bright and the bathroom and back bedroom is really dim and the front bedroom is fine. He said that when he turned on the bedroom light that the plug in night lite turned on instead of off. And when he plugged in the vacuum nothing happened and the light went off. Any way I get there today and they showed which outlets didn't work and what lights are being affected so I plug in my tester and it said hot ground reversed. And when I started to turn the lights on the to see what was happening the son said there was smoke coming out of the gfi in the bathroom. Went in there and sure enough there was. So I disconnected the gfi and looked in several j boxes and could not find a loose connection. After the gfi was taken out the plug in tester showed that everything was ok and all the lights were now all back to normal brightness. My question is have any body ever seen anything like this and what am I missing?

Also the gfi is on a different circuit with the same neutral that is in question.

customer did call back tonight and say that one of the bedroom lights did get dim for a couple of seconds and then went back to normal.

Any thoughts or suggestions. And do you need more info.

thanks.

mdshunk

Sounds like you've got a textbook case of an open neutral. This may be an open neutral for a multiwire branch circuit, or an open neutral for the whole service. It is an open neutral problem just the same. This is a dangerous situation, and one of the few situations in a home that I'd call a genuine emergency. Advise him to unplug anything expensive, and get a sparky out there PDQ.

sckeeth

what would make the gfi burn like that and then once removed everything was fine. I have never seen anything like that before have you.

mdshunk

Bro, you have an open neutral situation, and that GFCI got fried with near 240 volts. Everything is not "fine". This sort of situation doesn't heal itself, unless you tightened a neutral pigtail wirenut of a MWBC when you replaced the GFCI.

sckeeth

That possibly could be why everything is "fine" I pulled off all the wire nuts and re twisted everything so that could be the reason everything is fine. At least for the moment until I go back tomorrow. Thanks for the info.

sckeeth

What I should of stated in my first post is that while I have been doing this for years (short compared to most here) I have never ran into this situation before. I have only read about it (loose neutral) and the symptoms. So with that said this is my first experience with being in this situation.

I was looking for wisdom of the people that have dealt with this before.

So, if your willing then here I go

There is three rooms in a row that have this circuit, first bedroom everything seemed to be fine second room is the bathroom where the lights were dim and the hall outside of the bathroom and bedroom lights seemed to be bright, and the third bedroom lights were dim. So with that info it would have to be somewhere after the first bedroom where the problem is right? It is only in that part of the house so would it be safe to say that it is not in the panel?
I did check all connections at the panel first and it did not appear to have any loose neutral connections.

Am I headed in the right direction?

A.W.Davis

Could be a fault on the poco side?

Call an electrician!

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sckeeth

if it was a fault on the poco side more than the 1 circuit would be affected.

jrclen

I'm curious, did you go back there? Is everything still "fine?"

Sportbilly

And how are the voltages?

Maybe the load is almost balanced now, hence no smoke, but the next time someone turns on the hairdryer, the VCR blows up. That would be suboptimal.

220/221

Smoke is not good.

Start at the service, if there are any 3 wire home runs, find where they split up and check neutral connections.

If there are no 3 wire home runs the problem is at the neutral lug/bus/wire/poco connection etc.

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Just because it's within code doesn't make it safe.

Just because it's against code doesn't make it unsafe.

JohnJ0906

Are the areas that got bright and dim part of a MWBC?

This was only part of the house and not the whole thing?

You have got an open neutral somewhere, that is for sure. It could be a loose splice, a loose connection on a receptacle, or a loose connection at the panel. If it is house-wide, it could be on the POCO side, (xfrmr connection) at the meter, or at the panel.

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"One Day at a Time"
All replies based on the 2008 NEC

sckeeth

To answer sportbilly the voltages from what I saw were fine both sides were 120.

220/221 there are no 3 wire homeruns and all the neutral connections in the panel were solid I checked them all.

Are the areas that got bright and dim part of a MWBC? Yes they are only part of them got bright and dim.

This was only part of the house and not the whole thing?
Yes it was only part of the house.

After everything was said and done and everything seemed to be fine I ran the vacuum at all the receptacles and the vacuum ran fine and all lights were normal.

The only loose wire was on the gfi on the neutral and it did pull out of the back fairly easily but this was after it came through the light above the sink and it ended at the gfi it didn't go anywhere after that.

I will be going back there thursday as I couldn't go back today, the breaker was turned off until I could get back.

mdshunk

Now hang on a second. How do you not have any 3-wire home runs, but the areas that were affected were part of a multiwire branch circuit? This isn't adding up, since they're the same thing.

220/221

Lights get bright + no MWBC's = failing service neutral SOMEWHERE. If it's not in the lug/feeder, it's one of the utility co's connections.


Call POCO. They will send someone out immeadiately. Out here, they will put a 1000 watt load on one leg while reading voltage on the other, then do the same on the other leg.

__________________
Just because it's within code doesn't make it safe.

Just because it's against code doesn't make it unsafe.

sckeeth

My mistake I mis read that yes there are 3 wire homeruns. Sorry for the confusion.

220/221

Ok then.


The smoking gfi is probably on one leg of a MWBC. You need to find the homerun and check the connection where the circuits split off. You will likely find a loose neutral there.

__________________
Just because it's within code doesn't make it safe.

Just because it's against code doesn't make it unsafe.

sckeeth

Well I went back and continued my search for all j-boxes and and checked everything associated with these two circuits. When I took out the receptacles 11 out of 12 of them either both neutrals or one just fell out as I was removing it from the box as well as the hot wire. I did see evidence of arcing as some of the wire was pitted. Thanks to all for the advice and help.

I also advised him that we check every other receptacle in the house because of what was found in only three rooms.

My question is if there was a loose connection in the service wouldn't the whole house have a problem not just one circuit. I only ask because several people mentioned that.

Magnettica

Quick answer to your question is yes.

However, if the grounding and bonding is not done properly, the electrons that normally flowed on the grounded (neutral) conductor, will now flow exclusively somewhere else, like a water pipe or any material that can conduct electricity (objectionable current flow, NEC 250.6). This is the primary reason for NOT bonding neutrals and grounds on a sub panel or device box.

This is an outstanding article that might explain it a little better: The Shocking Truth About Grounding Electrode Conductors

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220/221

I'd say yes, unless the stars were aligned just right. There would be a slight chance that it would only show in one area while you were there. If all the lights were off and there was nothing plugged in and turned on any receps of one phase it may not show system wide.

A bad connection like that can also temporarily correct itself under load by welding itself back together from the arcing.

Find your home runs.

__________________
Just because it's within code doesn't make it safe.

Just because it's against code doesn't make it unsafe.