# Panel Overheating



## Possum95 (Jun 2, 2015)

I have an odd situation it seems. Working on large hog buildings, they have a 400 amp single phase service coming into the main building. That service is split into 2 200 amp services with disconnects for each. At the panels inside the building we are burning up breakers on a regular basis. Most of the load in the panels feed 240 volt motors for fans and 2 for feed systems. The total load on the panel in full operation is 157 amps per leg, but that is the max and doesnt happen very often about 125 amps average. The breakers in the panel are all double pole 20 amp the draw on these breakers is all below 14 amps per leg. The main 200 amp breakers dont show any signs of overheating but all of the 20 amp breakers seem to be at least 45deg above room temperature and the wires going into the breakers show no signs of heating it is only the breakers. I have replaced one of the two panels already from a standard residential siemens to a WP 200 amp ge due to the fumes and moisture in the building. Nothing I have tried has changed anything with the breakers getting to hot and failing. I tried contacting GE and there engineer is tryingb to say the frequency is off. I have tested the Hertz a few times and have found variations but the local electric utility insists that there line is fine. Any suggestions on what to try or how to test for another problem would be greatly appreciated I have been battling this on and off for 2 years. Yes the problem does seem to come and go. Incoming voltage stays pretty steady 246 volts phase to phase, 122 volts A phase to ground, 123 volts B phase to ground.


----------



## RIVETER (Sep 26, 2009)

The only way electricity causes excessive overheating of either the wiring or the breaker is due to excessive energy loss. Recheck your breakers with a good...sensitive ohmmeter for resistance across the contacts.


----------



## wildleg (Apr 12, 2009)

are the busses copper or al ? can you see oxidation on the busses ?


----------



## Possum95 (Jun 2, 2015)

I have tested all the breakers. Replaced one whole panel and the breakers inside. Checked for any voltage drop in the circuits. All this comes up empty. There are no problems in the building with the elctrical connection anywhere no signs of overheating on any of the equipment. Just the breakers getting hot and failing. I have replaced the same breaker within a week of each other. I can take an old breaker out and install a new one and within an hour it is getting hot. I have replaced 37 breakers in the past 2 years in 2 panels. As of yet I havent been able to find an answer. I also service 6 other barns that where set up the same way in different locations and have no problems with them.


----------



## Possum95 (Jun 2, 2015)

Busses are copper even in the cheaper panel.


----------



## bkmichael65 (Mar 25, 2013)

Could the motors be short cycling and building up heat from seeing frequent inrush currents?


----------



## RIVETER (Sep 26, 2009)

Possum95 said:


> I have tested all the breakers. Replaced one whole panel and the breakers inside. Checked for any voltage drop in the circuits. All this comes up empty. There are no problems in the building with the elctrical connection anywhere no signs of overheating on any of the equipment. Just the breakers getting hot and failing. I have replaced the same breaker within a week of each other. I can take an old breaker out and install a new one and within an hour it is getting hot. I have replaced 37 breakers in the past 2 years in 2 panels. As of yet I havent been able to find an answer. I also service 6 other barns that where set up the same way in different locations and have no problems with them.


I'll ask the obvious.. What is the circuit amperage draw on the circuit conductors? What is the ambient temperature at the panel surround?Shoot the breakers with a cheapo Harbor Freight heat sensor/ IR laser.


----------



## wildleg (Apr 12, 2009)

I think you need to put a recording meter (a decent one) on some of these ckts and find out what's really going on.


----------



## Possum95 (Jun 2, 2015)

RIVETER said:


> I'll ask the obvious.. What is the circuit amperage draw on the circuit conductors? What is the ambient temperature at the panel surround?Shoot the breakers with a cheapo Harbor Freight heat sensor.


 
Average amp draw is 14 amps per phase per breaker when motors are running. Last IR temp reading I did the Room was 85deg the panel itself was reading 103 deg, the breakers with fans running where 122 deg, the breakers with fans off where 106 deg, the main was 103 deg, and the wires coming off the breakers that where 122 deg only read 99 deg 6 inches from the breaker.


----------



## Possum95 (Jun 2, 2015)

wildleg said:


> I think you need to put a recording meter (a decent one) on some of these ckts and find out what's really going on.


I have tried a couple different recording meters that monitor amps and volts but couldnt find any big variations. voltage holds steady all the time even on motor start ups. Amperage stays almost constant after startup. When the fans start they run a minimal of 15 minutes and most of the time its a lot longer. once the heat hits for the summer about all of them run constant. Should I look for a different recorder that monitor something besides amps and volts?


----------



## RIVETER (Sep 26, 2009)

Possum95 said:


> Average amp draw is 14 amps per phase per breaker when motors are running. Last IR temp reading I did the Room was 85deg the panel itself was reading 103 deg, the breakers with fans running where 122 deg, the breakers with fans off where 106 deg, the main was 103 deg, and the wires coming off the breakers that where 122 deg only read 99 deg 6 inches from the breaker.


All of that leads to defective breakers. I know the odds are not there but what else would it be...except the remote possibility the the buss is somehow compromised. I like to experiment and if you do, as well, try to place, temporarily, a small panel there and feed the 122 degree circuit through a breaker in it. Check the temperature.


----------



## Cow (Jan 16, 2008)

Have you tried putting an empty breaker space between each breaker for air circulation?

Are these bolt on breakers or stab ins?


----------



## RIVETER (Sep 26, 2009)

Cow said:


> Have you tried putting an empty breaker space between each breaker for air circulation?
> 
> Are these bolt on breakers or stab ins?


If his wire is correct to the breaker size and the load is less than 80% of that breaker, it should not overheat.


----------



## bkmichael65 (Mar 25, 2013)

I just noticed you're talking about a hog operation. Could the methane be oxidizing the buss or breakers and causing resistance heating?


----------



## RIVETER (Sep 26, 2009)

bkmichael65 said:


> I just noticed you're talking about a hog operation. Could the methane be oxidizing the buss or breakers and causing resistance heating?


If all of the hogs are hanging around the electrical panel I think I would give them something to do.


----------



## varmit (Apr 19, 2009)

From your description, my initial guess would be that there is a problem with the subfeed from the service to the 200 A panel. Is this wire aluminum? If so, the conductor(s) could be damaged (partially vaporized) and serving as a current limiter. If copper, this can still happen, but not as common.

I would do a "fall of potential" test on all fuses, breakers, terminations and service/feeder conductors. Also, megger all conductors. You could have some insulation breakdown in a hog house environment. With the FOP test, if you read more than about 30 millivolt across a terminal or a contact, there could be a problem.


----------



## Roger123 (Sep 23, 2007)

Here is my 2 cents. 

You have a rather high temperature environment, with decent size motor loads, that run at times continuously, all on non-bolt on GE & Siemens' breaker panels. 

My suggestion: Install bolt on commercial Square D, QO or Eaton CH breaker panels.


----------



## telsa (May 22, 2015)

*Pigs = Urea Factory*

Urea + heat + oxygen = nitrates ...

FYI the above chemistry is EXACTLY how the Chinese discovered the basis for making black powder explosive.

Unlike "Barter Town" -- the Chinese (a millennia ago) discovered that hogs produced urea like crazy. When dried it (pig liquid) crystalizes as a white powder (it oxidizes on the spot to the nitrate form. After playing some chemical games (purification) the way was clear to make black powder, guns, and solid fuel rockets.

So, I have to ask: What's the air quality in and around your panels? Drippy nitrates can weep straight back up into your feeders -- and do a complete number on even copper. Dilute nitric acid will NEVER stop attacking copper until the ENTIRE chuck is in solution. 

This kind of damage will rarely be evident from any DMM. Even an analog meter will 'think' your feeders are absolutely fine. Look for any sign of nitric acid attack: blue or green copper. ( Blue = Cu + ; Green = Cu ++ ; these are the only two oxidation states for copper.)

They also do a bang up job on copper anything else, too.

Have you polished the bussing in the panel? I've seen corrosion on old bussing that knocked off a full 1.5% of the voltage -- RIGHT THERE. In which case, even a new set of breakers ends up right back 'on the griddle.'

&&&&&&&&&

BTW, you'd be miles ahead to install VFD for your blowers. 

Backing off their volume throughput by 20% can cut their power demand by 50%. (!)

While a true statistic, this gain is too great for most to believe. It still remains true, though.

It's possible to run VFDs from single phase power to support 3-phase induction motors. You just have to oversize them -- which is not economically painful at all.

Tripling the rating of a VFD does NOT triple the cost... not by a long shot.

I'm simply AMAZED that anyone is still running single phase blower loads night and day on America's farms. They are wallet busters.:no::no::no:

PS You HAVE double checked your blower motor bearings - right?

Reduced speed -- reduced back-EMF -- hefty current draw -- capacitor punishment, too.


----------



## Jmiester (Apr 8, 2015)

wildleg said:


> are the busses copper or al ? can you see oxidation on the busses ?


That is the first thing that I was going to ask


----------



## EJPHI (May 7, 2008)

It might be worthwhile to break open some of those failed breakers. You could then tell what broke and also confirm that you don't have cheap knock-offs.

EJPHI


----------



## 3DDesign (Oct 25, 2014)

I used to do service work on pig and dairy farms. My guess is the corrosive environment is causing a bad connection between the buss and breakers. I'm also guessing it's causing the enclosure to rust.


----------



## Dan the electricman (Jan 2, 2011)

telsa said:


> Urea + heat + oxygen = nitrates ...
> 
> FYI the above chemistry is EXACTLY how the Chinese discovered the basis for making black powder explosive.
> 
> So, I have to ask: What's the air quality in and around your panels? Drippy nitrates can weep straight back up into your feeders n = Cu ++ ; these are the only two oxidation states for copper.


The Chinese discovered black powder via urea...nitrates wicking into feeders...LOL! This guys loves to make stuff up.


----------



## telsa (May 22, 2015)

Dan the electricman said:


> The Chinese discovered black powder via urea...nitrates wicking into feeders...LOL! This guys loves to make stuff up.


If you are so uneducated as to not know that the Chinese discovered black powder...

That they sourced their nitrates from pig urea...

Which is fulsomely documented...

Then I guess you'd not hesitate to embarrass yourself on the Internet.

Of course, the fumes at a pig sty are what makes it a pig sty.

&&&&

It's disgusting, but ALL ancient societies used urine -- animal and human -- as a commodity. Pigs produce urine prolifically; you should know at least that much.

If you don't know that urine decays into urea via evaporation...

Then it's high time you open a book on chemistry -- or at least Wiki before posting.

It literally took centuries before any serious substitute for pig urine was discovered as a source for nitrates -- THE limiting component in black powder.

Pigs are everywhere, nitrate deposits in nature are astonishingly rare: the salts of Chile. These massive salt deposits are now understood to be the result of bird guano deposited over eons of time.

Bat guano figured huge during the American Civil War. Any Southern father that could produce even 2 pounds of bat guano (from local caves) could exclude his son from the military draft for a whole year! The Union naval blockade had stopped all importation of nitrates for black powder. Yes, the crisis in gunpowder was THAT bad.

:no::laughing::no::laughing:


----------



## Dan the electricman (Jan 2, 2011)

telsa said:


> If you are so uneducated as to not know that the Chinese discovered black powder...
> 
> Never said that. I just doubted that they found it on a pig farm, as you implied...


I notice you ignored the "wicking into feeders" part. Who is "telsa" by the way?


----------



## don_resqcapt19 (Jul 18, 2010)

The following is from the UL breaker standard. The rise is over a 40°C ambient.


> The acceptable operating temperature of a circuit breaker is defined by UL in the UL489 standard (June 2011), which is listed below.
> 
> Terminations for standard rated breakers: Paragraph 7.1.4.2.2 says the temperature rise on a wiring terminal at a point to which the insulation of a wire is brought up as in actual service shall not exceed 50°C (90°F).
> 
> ...


----------



## telsa (May 22, 2015)

Dan the electricman said:


> I notice you ignored the "wicking into feeders" part. Who is "telsa" by the way?


But, ironically, they DID find the magic ingredient from pig farms. The other two ingredients, sulfur and charcoal -- both pulverized -- had been played with by the Chinese long before.

There is no documentary trail from the Chinese for their discovery of either paper manufacture, silk processing, or black powder, each an astounding discovery.

&&&&&

One of the very few industrial customers I ever had to service always showed astounding corrosion/ rust from processes that (unlike a chlor-alkali plant) didn't appear to be corrosive at all.

Yet, when you looked at the gear, the damage to contactors, relays, terminations -- simply astonishing -- then jaw dropping when one discovers the joint has been in service for only 20 months!

This is why I asked the question as to whether the terrible stink of a pig sty was leaving corrosion/ affecting his terminations. When the point of trouble is not obvious, you start taking a peak at even low probability possibilities. You would not believe the number of circuit faults that I've discovered by pursuing the 'unlikely.'

Corrosion at terminations/ busing is seen all the time in aluminum -- in every seaside location -- even miles inland. Somehow the salt mist is able to spread that far. Amazing, really.


{ My all time favorite circuit fault: apprentices made perfect make-up under a red wire nut. Problem: they didn't strip the conductors -- not a one! It was impossible to spot until it was busted open. Until that second the newly installed circuit looked absolutely perfect. It just would not turn the lights on! }

Don't conflate speculations with assertions. Please.

Just because something is scientifically possible -- even a proven fact -- that something may not pan out as having any bearing on a circuit fault. It's just something that you need to put your eyeballs on. Nothing more, nothing less.

"It can't be that!" -- those famous words spoken right before the most improbable glitch proves to be THE glitch.

Until it happened, I never would've believed that three #12s could go into a red wire nut totally un-stripped. Obviously, the mind was on idle and the mouth was on full bore!


----------



## micromind (Aug 11, 2007)

Interesting standard.......I could be reading it wrong, but apparently, it's ok to have the plastic handle of a breaker at 185ºF. 

I don't know about anyone else, but I'm pretty sure that if I were to turn off a breaker (especially a big one) and the handle was 185ºF, my hand would be seriously burned before I could get it to turn off. 

Though I don't doubt that the standard is real, I find it difficult to believe that a UL, usually known for nearly idiotic degrees of safety, would allow such a high temperature to be present at an object designed for human touch. 

Learn something new every day......lol.


----------

