# Always new gremlins lurking



## varmit (Apr 19, 2009)

In my fixing of junk equipment I thought that I had seen about every possible thing that could go wrong. Today I found a new problem.

i received a call about a bagging machine from a chemical processing plant where I do a lot of work. It was the typical, "The fuses blow when we turn the power on." I checked everything and the VFD and the control transformer were both shorted to ground - nothing unusual about that, just initially assumed age degradation.

Then checking further, all of the 480 volt wiring in the control panel, that was touching the enclosure or anything grounded would only read about 1 megohm to ground, with the wires disconnected on both ends. Some wires were only 18 inches (450 mm) long. None of these wires showed any physical damage. Everything in the panel had a sticky chemical residue on it and it appears that whatever this chemical is/was broke down the wire insulation completely. I replaced the VFD, transformer and all of the power wiring and all was well. The 120 volt control wiring did not seem to be a problem. I assume that the lower voltage would not bleed through the compromised insulation.

You never know what you will find doing Industrial maintenance. An open mind is required.


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## tates1882 (Sep 3, 2010)

Well at least you found it. I hate the weird problems that take forever to find.


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## micromind (Aug 11, 2007)

About 15 years ago, I installed ballfield lighting at one of the local parks around here. The branch circuits (20, 30 and 40 amp) ran underground in PVC about 30' from a building to the control panel. Then various distances to the poles. No conduit was overstuffed, and derating was within code. 

After about 2 or 3 years, breakers started tripping. Just about every wire megged bad. Some had blown up inside the PVC. 

So I repulled all circuits. All was well for another 2 or 3 years. Same trouble. 

I've pulled fricking MILES of wire, this was the only one that ever caused trouble. And twice in roughly the same time span.

I contacted a rep from one of the wire manufacturers (I don't remember which one), and sent a sample of the bad wire in. They determined that some sort of chemical in the water inside the PVC was attacking the insulation. 

I then pulled their recommended wire in (XHHW, if I remember......). It's been about 10 years, no trouble so far. 

Maybe they really do know their stuff......lol.


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## Legacyelectric (Sep 9, 2012)

micromind said:


> About 15 years ago, I installed ballfield lighting at one of the local parks around here. The branch circuits (20, 30 and 40 amp) ran underground in PVC about 30' from a building to the control panel. Then various distances to the poles. No conduit was overstuffed, and derating was within code. After about 2 or 3 years, breakers started tripping. Just about every wire megged bad. Some had blown up inside the PVC. So I repulled all circuits. All was well for another 2 or 3 years. Same trouble. I've pulled fricking MILES of wire, this was the only one that ever caused trouble. And twice in roughly the same time span. I contacted a rep from one of the wire manufacturers (I don't remember which one), and sent a sample of the bad wire in. They determined that some sort of chemical in the water inside the PVC was attacking the insulation. I then pulled their recommended wire in (XHHW, if I remember......). It's been about 10 years, no trouble so far. Maybe they really do know their stuff......lol.


Probably chemicals in the water from fracking! Haha


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## JRaef (Mar 23, 2009)

I had a cable fault happen on the incoming cables to a big 500HP compressor control panel from a nick in the insulation (assumed), so even though the main breaker of the panel was open, the cable ahead of it vaporized when the feeder in the main switchgear was closed. (the door was partially closed, but I lost my eyebrows and shoelaces on that arc flash!)

After I replaced the 500MCM incoming cables, I closed the breaker in the control panel and it tripped immediately. Apparently when that first cable vaporized, it coated EVERYTHING inside of the box with a thin film of copper, like a vapor deposition system. Just about everything in the box had to be replaced because it was reading low resistance to ground, including the entire 500HP soft starter. Thank goodness I was not the contractor that had pulled the original cables, the GC had his own guys do that.


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## Big John (May 23, 2010)

We've got a customer where something in their manufacturing process attacks fiberglass. Since fiberglass is a major component of the insulators in switchgear, that ain't good. We haven't noticed dielectric failure, but it weakens the hell out of it.

They kept calling us with switch and circuit breaker failures where they had single-phased or only one pole had closed or something similar, and it was always these fibgerglass driving arms and linkages that had snapped. That should be a very rare failure, and we fielded more than a half-dozen of them, all on different vintages of switchgear.

It's at the point now where whenever gear shows up for service, all the load-bearing fiberglass parts just get automatically replaced to help ward off failure. Only place I've ever seen that has this problem.


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## don_resqcapt19 (Jul 18, 2010)

varmit said:


> ... Everything in the panel had a sticky chemical residue on it and it appears that whatever this chemical is/was broke down the wire insulation completely. ....


What does it do to people??


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## John Valdes (May 17, 2007)

varmit said:


> In my fixing of junk equipment I thought that I had seen about every possible thing that could go wrong. Today I found a new problem.
> 
> i received a call about a bagging machine from a chemical processing plant where I do a lot of work. It was the typical, "The fuses blow when we turn the power on." I checked everything and the VFD and the control transformer were both shorted to ground - nothing unusual about that, just initially assumed age degradation.
> 
> ...


What type of wire is the control vs the power wiring?
MTW for control and THHN for power?

Might be good to find out which type took the chemical abuse and which type succumbed to the chemical abuse.
Please let us know.


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## MTW (Aug 28, 2013)

Did someone say mtw? 


Sent from my iPhone using electriciantalk.com


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## JRaef (Mar 23, 2009)

Yes they did. So how are you when it comes to chemical abuse?


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## micromind (Aug 11, 2007)

JRaef said:


> Yes they did. So how are you when it comes to chemical abuse?


Lol....good one!!!


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## varmit (Apr 19, 2009)

All of the panel wiring was MTW. The power to the panel was SO cable.


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## varmit (Apr 19, 2009)

don_resqcapt19 said:


> What does it do to people??


I am always concerned about the health risks when I work at this place. Some of the plant employees have been there over 20 years though. I guess that a person acclimates to the toxins to some degree. Part of this place runs liquids and another area runs dry dusty chemicals. I doubt that either are good for a person.


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## JRaef (Mar 23, 2009)

varmit said:


> Some of the plant employees have been there over 20 years though. ...


Yeah, but as you likely know, people worked in coal mines and asbestos factories for longer than 20 years before it all caught up with them too. We had a Johns Manville asbestos plant near here, ran for 80+ years. But a LOT of people died, including the wives of guys who worked there, because they would breath it every day from handling their laundry. The plant shut down over the lawsuits in the early 80s. A local paper was trying to interview people who had worked there last year some time, they couldn't find anyone, even looking for people who had moved away. Turned out they were mostly all dead 30 years later, even those who were only in their 30s when it was shuttered.


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## dronai (Apr 11, 2011)

Problem with a lot of those plants is all the processes to manufacture have some crap that's bad for you in there somewhere. We just had a welder welding strut to the machines, and I asked him if he was worried about welding galvanized metal, he didn't seem too concerned. Every man for himself !


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## micromind (Aug 11, 2007)

dronai said:


> Problem with a lot of those plants is all the processes to manufacture have some crap that's bad for you in there somewhere. We just had a welder welding strut to the machines, and I asked him if he was worried about welding galvanized metal, he didn't seem too concerned. Every man for himself !


I get the biggest kick out of guys who wear all the latest safety crap then smoke a half-dozen cancer sticks at breaks and lunch.


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## JRaef (Mar 23, 2009)

micromind said:


> I get the biggest kick out of guys who wear all the latest safety crap then smoke a half-dozen cancer sticks at breaks and lunch.


So true. I once witnessed a guy wearing a breathing filter because he would be exposed to asbestos when working on removing "popcorn" ceilings, then push it to one side to get a cigarette in his mouth.

I also like the people who post in an internet forum about the dangers of "radiation" from cell phone technology, then later divulge that they have a wireless router they are using to post that info and they are sitting in front of a CRT monitor, probably in their Mom's basement so they are breathing radon gas.


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## varmit (Apr 19, 2009)

JRaef said:


> Yeah, but as you likely know, people worked in coal mines and asbestos factories for longer than 20 years before it all caught up with them too. We had a Johns Manville asbestos plant near here, ran for 80+ years. But a LOT of people died, including the wives of guys who worked there, because they would breath it every day from handling their laundry. The plant shut down over the lawsuits in the early 80s. A local paper was trying to interview people who had worked there last year some time, they couldn't find anyone, even looking for people who had moved away. Turned out they were mostly all dead 30 years later, even those who were only in their 30s when it was shuttered.


I was actually referring to my amazement that these folks are still alive.


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