Receptacles burning

[hmspe]

I had an electrical contractor call today about a mobile home that has devices catching on fire. The air conditioning thermostat has burned twice. Several receptacles have burned. The attached picture is of a GFCI receptacle that was installed today to replace a burned receptacle. This was in the middle of a run with a refrigerator receptacle upstream and one other small appliance receptacle downstream. This receptacle burned less than two hours after installation. The electrician was not in the building when this happened but was on site. He reported that the connections were correct and tight. Based on the tenant's report nothing was plugged in to this receptacle. The electrician took the receptacle apart after taking the picture and reported that there is no discoloration or other visible damage inside. Several other receptacles in other rooms have also caught fire. The POCO has looked at the site and found no problems. The EC has checked power at the panel and it looks like it should.

Any thoughts as to what might be going on?

 

[al hildenbrand]

Were there occupants? My first suspicion, especially after noting the lack of discoloration even on the TR vane closing the neutral slot, is that this damage is external, and not of electrical origin.

 

[don_resqcapt19]

Were there occupants? My first suspicion, especially after noting the lack of discoloration even on the TR vane closing the neutral slot, is that this damage is external, and not of electrical origin.

It looks that way to me too.

 

[Saturn_Europa]

I agree with Al. Its hard to imagine an brand new outlet installed by a EC burning up with nothing plugged into it. If the EC was there and can verify that there was nothing plugged into the outlet, I would put a clamp on amp meter on the branch circuit. I would also thermal image the outlets and thermostat.

Post back what you find

 

[GoldDigger]

If the wiring is in some way responsible, I would look for an intermittent service neutral.

 

[meternerd]

Looking at the pic, it's pretty obvious that the "flame" came from below the neutral hole. No way it was an internal wiring problem. Look for insurance fraud or a pyro youngster. Just my cynical opinion though...not casting any stones.

 

[domnic]

burned

burned

looks by the burn pattern some one is playing with a lighter or torch.

 

[sii]

Definitely looks like the neutral slot is deformed in a way that looks like there was nothing plugged in at the time of the fire.

 

[user 100]

Were there occupants? My first suspicion, especially after noting the lack of discoloration even on the TR vane closing the neutral slot, is that this damage is external, and not of electrical origin.

It looks that way to me too.

Definitely looks like the neutral slot is deformed in a way that looks like there was nothing plugged in at the time of the fire.

I agree- barring a unicorn or some other detail we don't yet know, it appears someone is scheming, screwing with the ec or as said above playing w/a lighter. Be interesting to know type of burns the scorched tstat has.

 

[tishelectric]

Looks like.someone took a lighter to it

Sent from my SM-N920V using Tapatalk

 

[RLyons]

This is what a burnt GFI looks like when nothing is plugged into it :lol:


The cause:

 

[ATSman]

Ungrounded Neutral

Ungrounded Neutral

I agree with Digger,
Have seen many Y-connected sources on 208/120V services where the neutral was loose or never grounded raising the V on other phase conductors to cause this type of insulation damage on 3 phase systems.

 

[hmspe]

Thanks for the replies. I was thinking either a neutral problem or foreign power on the water piping until I saw the photo. This is a rental unit that is occupied by the owner's grandson. The picture looks like intentional vandalism to me. Not an easy thing to discuss with the owner.

 

[JFletcher]

Thanks for the replies. I was thinking either a neutral problem or foreign power on the water piping until I saw the photo. This is a rental unit that is occupied by the owner's grandson. The picture looks like intentional vandalism to me. Not an easy thing to discuss with the owner.

No it isnt.

If the kid is fairly young, just have the granddad tell him you're going to set up cameras. If he's old enough to call that bluff, real hidden cameras might be needed.

Then again, your role of microcosm arson investigator seems complete; the fires are not electrical in origin.

 

[domnic]

receptacles

receptacles

I agree with Digger,
Have seen many Y-connected sources on 208/120V services where the neutral was loose or never grounded raising the V on other phase conductors to cause this type of insulation damage on 3 phase systems.

NO WAY. look at the picture.

 

[iwire]

I agree with Digger,
Have seen many Y-connected sources on 208/120V services where the neutral was loose or never grounded raising the V on other phase conductors to cause this type of insulation damage on 3 phase systems.

No way, there is no way a lost neutral accounts for the damage in that picture.

You could wire those 120 volt devices directly too a 240 volt source and they would be fine.

 

[ptonsparky]

Looks to me like someone is lonesome and wants attention. They also have a nice little butane torch like I use to light my charcoal grill.

 

[user 100]

No way, there is no way a lost neutral accounts for the damage in that picture.

You could wire those 120 volt devices directly too a 240 volt source and they would be fine.

I agree- those devices can easily handle way more than 120. In fact many very old devices (sw's, recs, lamphldrs, etc) were dual rated 125v/15a and 250v/ 10a due to some obscure rule about lighting circuits that vanished in the '50s. And the guts of those devices were probably no more meatier than their descendants today.

Think too of all the diy's that have gotten the wiring/ tab breaking scheme wrong while replacing a 5-15 part of a mwbc or 2 cts w/ their n's run to the same duplex.:lol:
The receptacle survived, but the microwave didn't.

 

[GoldDigger]

No way, there is no way a lost neutral accounts for the damage in that picture.

You could wire those 120 volt devices directly too a 240 volt source and they would be fine.

Receptacle, sure. GFCI receptacle probably not.
Also note that I said *if* the problem is wiring. I agree that the one receptacle pictured is external damage.

 

[iwire]

Receptacle, sure. GFCI receptacle probably not.
Also note that I said *if* the problem is wiring. I agree that the one receptacle pictured is external damage.

I have seen 240 applied to a GFCI receptacle, it goes pop and the smoke comes out.

No fire. Doubt UL would list them if a predictable overvoltage made them burst into flames.