# Melting neutral wire in panel



## WarnerConstInc.

So I was in my garage cleaning, my brother was working on a Bronco.

100A panel in garage, fed with #2 wire, all 20A breakers

One circut closest to the panel, 5 outlets, 12/2, 20A outlets.

Plugged into this was a set of work lights and a squirrel cage set on a 
T-stat, kicks on every 15 minutes or so.

Work lights started cutting in and out, I walked by the panel and smelt something hot.

Opened panel and that circuts neutral wire's insulation was melting.

cut wire back re-installed and shut that light off. Had no more problems.


Is it safe to say his work light was having an issue?

Or issue with panel/wiring.

Nothing else in garage was affected/8 other circuts or so.


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## Winchester

Wow, talk about fire hazard!

My unprofessional guess is that it is a shared neutral with too much load on it. It's sharing load with another circuit somewhere that it shouldn't be (i.e. same phase?)... 

My other unprofessional guess is the circuit was overloaded and the breaker wasn't tripping.

I hope that is the only spot the insulation was damaged.


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## Leo G

Sounds like a loose neutral, extra resistance heated it up. Some sparky should be along soon enough to straighten us all out.


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## Winchester

*tap tap tap*

Man, the electrical section is dead compared to carpentry. They must all be over at electriciantalk talking bad about all of us on contractortalk. (That's what the painting guys do!)


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## Magnettica

Does the neutral conductor share a pair of ungrounded conductors?

One red, maybe one black?


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## WarnerConstInc.

Magnettica said:


> Does the neutral conductor share a pair of ungrounded conductors?
> 
> One red, maybe one black?


 
no it doesn't.


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## Magnettica

Some kind of buried splice in the wall maybe? Need to amprobe it and figure it out. Maybe it was just a loose connection at the bar.


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## mrmike

Winchester said:


> Wow, talk about fire hazard!
> 
> My unprofessional guess is that it is a shared neutral with too much load on it. It's sharing load with another circuit somewhere that it shouldn't be (i.e. same phase?)...
> 
> My other unprofessional guess is the circuit was overloaded and the breaker wasn't tripping.
> 
> I hope that is the only spot the insulation was damaged.


:clap:

I agree here, as the work lights probably put it over the amperage of the wire and will start melting at a weak point, usually where the insulation is open. 
I would check to see how much stuff is on this circuit with that neutral wire..
I would also check this breaker to determine if it is the right amperage for the wire. If it is, I would change it as it should have tripped. Don't ever think a breaker will always trip. They are sitting there for maybe years, & believe it or not, they will collect dust inside of it, as an example. We had many,many, breakers in the plant I worked in, that would not trip. A co-worker of mine actually had a 40 amp single pole breaker rigged to short out circuits in the field to try to trip the breaker he was looking for. THIS WAS DANGEROUS & is probably still doing it. I think he even burned up a few!! Anyhow, I just used this for an example to show that breakers do not always trip at their rated ampacity............


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## Celtic

Leo G said:


> Sounds like a loose neutral, extra resistance heated it up.


That would be my conclusion as well.

I would also check/tighten the connections at each device to avoid any "complications" further down the road.


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## Celtic

Winchester said:


> My other unprofessional guess is the circuit was overloaded and the breaker wasn't tripping.


A question:
IF the circuit was overloaded and not tripping, why did the hot conductor not suffer a similar fate as the neutral?





mrmike said:


> .... I just used this for an example to show that breakers do not always trip at their rated ampacity............


Some brands are notorious for not tripping...Federal Pacific [FPE] comes right to the top here.


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## WarnerConstInc.

No buried splices all wall cavity's are still open, the outlet that the light was plugged into was the first one in the circut from the panel about 3' away.

20A breakers, 12/2 wire, 20A outlets.

Does anyone read? All that was in my initial post here. 

Celtic I dont know what kind of breakers they are, I know that the GE replaces the ones that are in the panel.
I had to replace the 100A main in the panel, it was arching out for some reason.

I still have a feeling that it was my brothers cheap ass work light he bought.


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## Celtic

WarnerConstInc. said:


> I still have a feeling that it was my brothers cheap ass work light he bought.


Nope....poor connections at the neutral bus on that branch circuit.

The light ~ lemme guess: A 1500w quartz stand?


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## woodchuck2

Chances are regardless the cost of the lamp that the cord on it is smaller than the wire feeding the circuit. So IMO the lamp is not the problem. As stated above by others it is most likely a loose nuetral or a corrosion problem. No pics to go by so who knows other than you. Now that the nuetral is tight i would have the circuit tested for amp draw, wouldnt hurt to replace the breaker either. Whats a breaker cost, $5 at most. Cheap insurance in my book.


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## Winchester

Celtic said:


> A question:
> IF the circuit was overloaded and not tripping, why did the hot conductor not suffer a similar fate as the neutral?


Because rarely anything happens the way you expect it to


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## Murray Ritchie

*Heat vs Current*

It has been suggested that the breaker should be changed out that it should have tripped. That may not be true in such cases as this. 

It is true that current produces heat. More current, more heat. Drawing enough current, producing enough heat, to melt the insulation at the point of termination, could only be done if the neutral is shared. Otherwise the heat damage would be witnessed on the hot conductor coming off of the breaker too.

If the neutral was making poor connection to the bus, the resistance goes up, causing less current to flow. Meaning the heat is being generated by the continious making and breaking of the path of current to flow. When the circuit is under load, and is opened and closed, an acring occurs at the break and make point. This arcing will produce enough heat to burn a house down, let alone plastic insulation.

Verifying and knowing that the neutral is not shared, this is probable cause. 

It hasn't been stated if the conductors were of copper or aluminum. But have seen in repeated cases as this in Alum. installations. Because of the properties of the al conductor to change physically over time.


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## WarnerConstInc.

hang on guys I will go pop the cover off the panel and snap a few pics.


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## WarnerConstInc.

heres the end of the wire in the first picture


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## WarnerConstInc.

last one shows outlet that light was pluged into next to panel

Now dont give me crap about how not neat and tidy the panel is inside.

Oh I lied, Siemens is what replaces the breakers that are in there.

I believe when my house was re-wired this was the old panel from in the basement.


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## Murray Ritchie

*My goodness!!!!*

well its an old one for sure.....but rules out the aluminum, and would suggest poor connection at the neutral bus.


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## mdshunk

It heated up right at the bar... right at the point of high resistance. Resistance=heat. Loose connection! Don't over think this.


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## WarnerConstInc.

That is what my friend said today when he stopped by. He is the electrician that I use here.

Would it be worth my time and money to swap that old panel out for a new one or not?


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## Celtic

WarnerConstInc. said:


> Would it be worth my time and money to swap that old panel out for a new one or not?


Unless my eyes device me [and my monitor/glasses are dusty]...that is FPE.

I would change it


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## Celtic

duplicate...delete


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## WarnerConstInc.

At least its not a push-o-matic!


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## Celtic

WarnerConstInc. said:


> Celtic I dont know what kind of breakers they are, I know that the *GE* replaces the ones that are in the panel.





WarnerConstInc. said:


> Oh I lied, *Siemens* is what replaces the breakers that are in there.
> 
> I believe when my house was re-wired this was the old panel from in the basement.





Celtic said:


> Unless my eyes device me [and my monitor/glasses are dusty]...that is* FPE.*


Time to scrap some dust off some sheet... :whistling


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## Celtic

Is the garage detached?


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## WarnerConstInc.

Yes Detatched garage


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## Celtic

It looks in sad condition - KO's missing and such - although it still functions...after having changed the MCB already...what's left to change?
the bus?
a handful of CBs?

How old are the existing CBs?


Little things add up to be an annoyance.


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## WarnerConstInc.

Celtic said:


> It looks in sad condition - KO's missing and such - although it still functions...after having changed the MCB already...what's left to change?
> the bus?
> a handful of CBs?
> 
> How old are the existing CBs?
> 
> 
> Little things add up to be an annoyance.


 
No Idea how old the CB's are
New bus, 6 new 20A CB I dont have anything 220 hooked up so the one Double CB makes me no difference right now.

Plus it is not a very big 100A panel to begin with.
Speaking of that I think they put the smallest 200A panel they could find in the basement.


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## mdshunk

WarnerConstInc. said:


> No Idea how old the CB's are...


early to mid 70's would be my best guess. I'm pretty sure that's an old ITE panel, but there's a dozen brands that will work fine in that panel.


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## WarnerConstInc.

I will probably just swap out everything, panel and all! Sure wont hurt anything.

Thanks.


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## mdshunk

WarnerConstInc. said:


> I will probably just swap out everything, panel and all! Sure wont hurt anything.
> 
> Thanks.


I'm a little bit puzzled why you feel compelled to do that? Functionally, there's not a blessed thing wrong with what I see there. Get a couple breaker filler plates (or pop in a spare breaker), if you have extra knockouts out of the cover. Pop a couple in the knockouts in the bottom. I could make that panel "legal" for about 5 bucks. 

On the other hand, a new 100 amp subpanel is probably less than 50 bucks.


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## WarnerConstInc.

Ok, I can start with swapping the CB's, the knocouts on the cover are right, no empty's.

That is pretty dang easy then.

I dont know, just thought it would look nice with a new panel.


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## mdshunk

WarnerConstInc. said:


> I dont know, just thought it would like nice with a new panel.


Yes, if you simply want a new one... go for it. Just don't think you had some scientific reason other than you wanted it. :thumbsup:


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## Celtic

WarnerConstInc. said:


> I dont know, just thought it would like nice with a new panel.


What's the plan for the walls...rocked or not?

The view from the horse drawn carriage is always the same :laughing:


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## mrmike

As many of you have stated a loose connection-high resistance causing this, but it took more than that as there are many, many loose connections in panels especially at the neutral bars, & if that was the case there would be many more houses burning down. I used to do preventative maintenance in our plant,, to check & tighten all connections in Mcc panels & switchgear on a shutdown & there were many Unbelieveable loose connections, but they did not burn like this wire. It took more than that.. 
I have also experienced many arcing connections in industry & As I stated in another post I was an infrared specialist to find these connections with an infrared camera & found many and I had to analyze them & wrote reports for them & I can tell you from personal experience, that wire burned up from more than a loose connection. Yes it probably started there because of a little higher resistance, but It had beacoup amps on it, more than it is rated for. Usually you did not see them burn on each end as other posts questioned. I have actually seen a whole run of a wire burned up because of amperage exceeding the rating of the insulation of the wire, because the breaker did not trip. 
And take heed it is not just Federal pacific that might not trip............


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## WarnerConstInc.

Celtic said:


> What's the plan for the walls...rocked or not?
> 
> The view from the horse drawn carriage is always the same :laughing:


Eventually I will rock the walls, this is my house so there is no telling if that will actually happen or not.

One end of garage is insulated and sheet rocked. there is another spot that is insulated with a few sheets of drywall up.

So if that is an indicator.


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## Celtic

WarnerConstInc. said:


> So if that is an indicator.


That seals the deal...change it out.


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## JohnJ0906

Celtic said:


> A question:
> IF the circuit was overloaded and not tripping, why did the hot conductor not suffer a similar fate as the neutral?


Added resistance of the loose connection kept the amperage low enough not to trip the breaker.



mdshunk said:


> It heated up right at the bar... right at the point of high resistance. Resistance=heat. Loose connection! Don't over think this.


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## Brian Senick

WarnerConstInc. said:


> So I was in my garage cleaning, my brother was working on a Bronco.
> 
> 100A panel in garage, fed with #2 wire, all 20A breakers
> 
> One circut closest to the panel, 5 outlets, 12/2, 20A outlets.
> 
> Plugged into this was a set of work lights and a squirrel cage set on a
> T-stat, kicks on every 15 minutes or so.
> 
> Work lights started cutting in and out, I walked by the panel and smelt something hot.
> 
> Opened panel and that circuts neutral wire's insulation was melting.
> 
> cut wire back re-installed and shut that light off. Had no more problems.
> 
> 
> Is it safe to say his work light was having an issue?
> 
> Or issue with panel/wiring.
> 
> Nothing else in garage was affected/8 other circuts or so.


It could have been that the light was drawing too much i had a simmilar problem with a pool filter i also could have been loose and it might have been arking


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## Brian Senick

WarnerConstInc. said:


> That is what my friend said today when he stopped by. He is the electrician that I use here.
> 
> Would it be worth my time and money to swap that old panel out for a new one or not?


 arty: i dont think you need a new pannel but if it makes you feel safer than do what you have to do


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## Brian Senick

I wouldnt swap out the pnnel just make sure all the connections are tight and find out what that light was drawing (power ) because you said everything else was ok try changing the breaker before you change the pannel


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## WarnerConstInc.

Man you electricians are way nicer than the plumbers:laughing:.

I swapped out the CB's and went over all connections inside the panel and the outlets on that circut.

Hopefully this will take care of it. If not I will let you know!!

Thanks guys!!:thumbsup:


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## 220/221

> It heated up right at the bar... right at the point of high resistance. Resistance=heat. Loose connection! *Don't over think this*.


You had a problem, you fixed it.

If it was always this easy we would be replaced by carpenters.:laughing:


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## ampman

loose neut. seen alot of that did anyone see neut. and ground tied together


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## joelv1967

I didn't take the time to read ALL the posts. Sorry if this is redundant.
First, check to see the amperage leaving the breaker and the amperage returning on the neutral. If somehow two or more neutrals from seperate circuits got tied, then you could have an over current situation during heavy load conditions. If this is not the case, the second thing is to check that the breaker is functioning. Lastly, check for any physical damage to the neutral. If it got smashed or nicked or pinched, it could've altered it's capacity. I strongly doubt that it is the breaker or the hot conductor as this is a higher current side than the neutral, and any overcurrent through a faulty breaker should damage the hot first.


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## joelv1967

Also.......A previous posted mentioned that the breaker should have tripped. That is not necessarily true. It is completely possible to be under current at the breaker and over current at the neutral. That is why It is important to make sure some neutrals did get tied that shouldn't have


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## sparks134

ampman said:


> loose neut. seen alot of that did anyone see neut. and ground tied together


Yep, BIG code violation there!!! Fix that NOW!!!


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## thom

since the original post was 22 months ago, I'd guess the issue is resolved by now, either by repair or fire.


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## WarnerConstInc.

I have not had a problem since I put all new breakers in and made sure all the neutrals were tight. Thanks for your concern.


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## Leo G

Is that before or after your garage burned down?


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## sparks134

WarnerConstInc. said:


> I have not had a problem since I put all new breakers in and made sure all the neutrals were tight. Thanks for your concern.


I hope you separated the neutral and ground bars!!!


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## WarnerConstInc.

sparks134 said:


> I hope you separated the neutral and ground bars!!!


Sure.


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