# Hot Breaker



## Podagrower (Mar 16, 2008)

I have a GE panel with a 60 amp breaker feeding an AC unit. While running, the AC unit pulls 17 amps. The breaker gets hot. Very hot. About 180 degrees according to the IR. I looked for loose connections and (I think) all the standard items to check. I put in a new breaker (it worked on TV), and there is no difference.
Yes, the ac runs constantly, it is Florida. 

Can anybody think of a good reason for this?


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## RePhase277 (Feb 5, 2008)

Podagrower said:


> I have a GE panel with a 60 amp breaker feeding an AC unit. While running, the AC unit pulls 17 amps. The breaker gets hot. Very hot. About 180 degrees according to the IR. I looked for loose connections and (I think) all the standard items to check. I put in a new breaker (it worked on TV), and there is no difference.
> Yes, the ac runs constantly, it is Florida.
> 
> Can anybody think of a good reason for this?


180 degrees is damn hot. You'd figure it would trip on thermal. Are you sure it is that hot? Have you put your hand on it? Is the breaker making good contact with the bus? Have you moved the breaker to another spot on the bus? Are the other breakers around it contributing to the heat?


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## MDShunk (Jan 7, 2007)

I agree. I think your gun is lying to you. The cheaper guns have a fixed emissivity set at closer to .80, so when you're measuring something that is actually perfectly black, it will read higher than it actually is.


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## Boneshaker (Jul 31, 2009)

Is it a plug is breaker? If so how what shape is the bus in? This sounds to me me like a loose connection between bus and breaker.


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## drsparky (Nov 13, 2008)

Are you reading 17 amps on both legs?


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## Podagrower (Mar 16, 2008)

InPhase. I moved the breaker, the breakers around it all have less than 5 amp loads. It is hot enough you can't hold your hand on it for more than a minute. It does trip sometimes.

MD. Thanks for that info, I know I can always learn something from you.

Bone. It is a stab in breaker. But the panel is pretty new, I wish that was the issue.

Drsparky. There is a slight variation between the two legs (less than .5 amp, which I attributed to controls being taped off one leg.

All good ideas so far, keep em coming


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## cguillas (Jun 25, 2009)

Half an amp lost works out to 60 watts at 120V. You know how hot a 60W lightbulb gets. Something is very, very wrong with your breaker or your stab.


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## MDShunk (Jan 7, 2007)

cguillas said:


> Half an amp lost works out to 60 watts at 120V. You know how hot a 60W lightbulb gets. Something is very, very wrong with your breaker or your stab.


A man could do a fall of potential test between the main lug and the load side lug on that branch breaker to find out if it's a bad stab.


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## cguillas (Jun 25, 2009)

Ah, at this point, just screw it. Pop out your breaker and hardwire the line across the panel to a ceramic lampholder and jimmy in a 60A fuse. You'll be fine. Never trusted breakers anyway.


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## MDShunk (Jan 7, 2007)

cguillas said:


> Ah, at this point, just screw it. Pop out your breaker and hardwire the line across the panel to a ceramic lampholder and jimmy in a 60A fuse. You'll be fine. Never trusted breakers anyway.


I sometimes still use that method when I'm troubleshooting a set of parking lot lights that are sometimes tripping a breaker. I put a fuse in each handhole in a weatherproof lampholder. Temporary troubleshooting measure.


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## RePhase277 (Feb 5, 2008)

So, where are you guys getting 60 A plug fuses?:laughing:


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## MDShunk (Jan 7, 2007)

InPhase277 said:


> So, where are you guys getting 60 A plug fuses?:laughing:


I put 15's in parking lot lights. I've never really used the screw-in fuse method for anything else. For control circuits, I use these little 1/8th amp things called "tattle tails".


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## cguillas (Jun 25, 2009)




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## RePhase277 (Feb 5, 2008)

cguillas said:


>


Surely you jest? That's good for at least 100 A!


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## user4818 (Jan 15, 2009)

You'd get pretty hot too if you had 17 amps running through you.


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## eds (Mar 21, 2009)

Whats is the nameplate MCA and Max Circuit Breaker/Fuse size. 60 amp breaker seems like a little overkill for this load. AC I looked at tonight had a MCA of 35.5 and Max breaker at 60


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## micromind (Aug 11, 2007)

As stated earlier, I'd do the fall of potential test. There should be very little voltage across the breaker, and more importantly, both legs should read roughly the same. 

Rob


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## Richard Rowe (May 25, 2009)

Have you got another Temp probe you can check it with? If it's really that hot you wouldn't be able to touch it for a second without getting burnt( I think you said you could hold it like a min). If you think it's a connection take it out clean them(with the power off) and use some of that connection paste with the ground up metal in it(I am known for my high tech descriptions). If you had a thermal camera it would tell the tale. We don't have one here at our plant but the local Power Co will come and bring theirs if I call. Yeah thats it buy a seven thousand dollar camera for a hundred dollar job.... man I am on top today!:thumbsup:


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## McClary’s Electrical (Feb 21, 2009)

cguillas said:


> Ah, at this point, just screw it. Pop out your breaker and hardwire the line across the panel to a ceramic lampholder and jimmy in a 60A fuse. You'll be fine. Never trusted breakers anyway.


 ????Hell with progress,,,we're gonna go back in time??? Whay would you recomend this or say such a thing?


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## drsparky (Nov 13, 2008)

It does not take very much resistance to cause your problem. At 120 volts 17 amps draw equals a circuit resistance of 7.58 ohms. To look at it another way, 2.4 amps per ohm and break it down further a 1/4 ohm of resistance equals .6 amps or 72 watts, that energy must be dissipated as heat in a very small area. This would be more than enough to make the breaker hot. 
I assume that you are using a GE breaker and not a “close enough” like a Homeline. Homeline will kill a GE panel by destroying the bus.:thumbsup:


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## brian john (Mar 11, 2007)

InPhase277 said:


> Surely you jest? That's good for at least 100 A!


 
American Penny 100 amps Canadian maybe 72 amps at best.


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## ElectricBill (Aug 14, 2009)

drsparky said:


> I assume that you are using a GE breaker and not a “close enough” like a Homeline. Homeline will kill a GE panel by destroying the bus.:thumbsup:


What is the cause of the bus damage. Other than mechanical fit issues are there other reasons which start bus bar damage such as dissimilar metals, humidity, or tin coating breakdown?


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## 220/221 (Sep 25, 2007)

> Can anybody think of a good reason for this?


Yes, the ac runs constantly, it is Florida.


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## Mountain Electrician (Jan 22, 2007)

Having lunch today at a diner a few towns over. A contractor I work with is doing a small project next to the restaurant, and we happened to be eating lunch at the same time. He told me that a breaker for a sub panel had tripped at the restaurant the last time he had eaten there, and asked me to talk to the owner since I was there. I guess he must have been angling for some free lunches. Whatever. I'm never adverse to a little "hero work", and from what he described it sounded like a easy fix. I told the owner i'd look at and give her an estimate. Here's what I found:

90 Amp 2 pole single phase Siemens breaker in a 2 circuit panel feeding a sub-panel about 50 feet away. The breaker, enclosure and SER cable leaving the panel are hot to the touch. Noticeably so, although all I had to troubleshoot with was a Fluke T5-600, so thermal imaging wasn't possible. 

No signs of a loose connection, and while I was there(15 minutes) the load never went above 62 amps on either leg. Voltage slightly low, around 236 but nothing to worry about. As far as I could tell, all the major loads were on in the sub-panel which really only consisted a 230 v a/c unit. Everything else were lights and receptacles.

No FOP test, as I didn't have a DMM with me, no thermal imaging (I don't even own a tool like that) so my best guess was a problem in the breaker. The owner said they had 2 A/C units fed out of that panel originally, but recently had moved one to another panel due to both units tripping the breaker often. Maybe the breaker has been weakened by being overloaded in the past? Anyway, I gave her a price to replace the breaker. If she calls me back I'll take a better meter with me to test things a little more.

I'm a damn fine replacement mechanic. I subscribe to the "throw parts at it" school of troubleshooting. :whistling2lus, maybe I can get a free lunch with every callback. They have great burgers!:thumbup:


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## nolabama (Oct 3, 2007)

Mountain Electrician said:


> No FOP test, as I didn't have a DMM with me


laugh at me if this is stupid but how do you do a fall of potential test with a DMM


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## Bob Badger (Apr 19, 2009)

nolabama said:


> laugh at me if this is stupid but how do you do a fall of potential test with a DMM


Place the meter on volts, put one meter lead on the line side and the other on the load side of the breaker.

The higher the volt reading the more impedance the breaker is putting into the circuit.


I am sorry I do not remember what the reading should be under.


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## nolabama (Oct 3, 2007)

thanks bob , btw good to have you over here


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## drsparky (Nov 13, 2008)

ElectricBill said:


> What is the cause of the bus damage. Other than mechanical fit issues are there other reasons which start bus bar damage such as dissimilar metals, humidity, or tin coating breakdown?


It is related to the mechanical fit. If you hold a Homeline back to back with a GE you will notice that the groove that contacts the outer rail slots do not line up. The GE groove is centered; the Homeline is offset to the side by 3/16 of an inch. If you put a Homeline in a GE panel it will sit cocked slightly diagonally. This effects the surface area were the electrical contacts meet the buss. The contacts will get hot and burn up the buss.:thumbsup:


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## steelersman (Mar 15, 2009)

drsparky said:


> It is related to the mechanical fit. If you hold a Homeline back to back with a GE you will notice that the groove that contacts the outer rail slots do not line up. The GE groove is centered; the Homeline is offset to the side by 3/16 of an inch. If you put a Homeline in a GE panel it will sit cocked slightly diagonally. This effects the surface area were the electrical contacts meet the buss. The contacts will get hot and burn up the buss.:thumbsup:


I'm confused, since he said it was a stab in panel. I take that to mean like the ****ty old Federal Pacifics. I don't know of any modern stab in breakers.


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## 480sparky (Sep 20, 2007)

steelersman said:


> ......... I don't know of any modern stab in breakers.


Say what?



Seimens.

ITE.









Sqaure D Homeline.

GE's THQL.

Cutler-Hammer.

Bryant.

Westinghouse.


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## steelersman (Mar 15, 2009)

to me those aren't stab in. Fed Pacific is stab in.


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## nolabama (Oct 3, 2007)

those are sorta stab-on not stab-in


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## 480sparky (Sep 20, 2007)

steelersman said:


> to me those aren't stab in. Fed Pacific is stab in.


Fed-Pacs are _Stab-Loc_. All the breakers I listed are stab ins.


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## ElectricBill (Aug 14, 2009)

What is the useful life expectancy of a breaker operating at 80% rate load? I have 40 year old ITE breakers that are failing due to the contacts burning up. BTW, I'm not referring to pushmatic just standard push on breakers. I certainly appears that 40 years is too long. It makes a good sales point if you are out on a service call and can convince the customer that the breaker and/or panel should be changed due to age.


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## Podagrower (Mar 16, 2008)

From what I can read of the nameplate, it shows MCA of 33ish, and max breaker of 40. The 60 amp GE feeds a disconnect with the properly sized 40 amp breaker in it. The 40 amp breaker does not get noticeably hot. But it is a Square D, maybe I should cram a Square D breaker in that GE panel?

Or, how bout the old ring terminal screwed right to the bus.:laughing:


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## steelersman (Mar 15, 2009)

480sparky said:


> Fed-Pacs are _Stab-Loc_. All the breakers I listed are stab ins.


Ok. Well at least I can say I learned something new today. Thanks 480.


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## Zog (Apr 15, 2009)

Podagrower said:


> I have a GE panel with a 60 amp breaker feeding an AC unit. While running, the AC unit pulls 17 amps. The breaker gets hot. Very hot. About 180 degrees according to the IR. I looked for loose connections and (I think) all the standard items to check. I put in a new breaker (it worked on TV), and there is no difference.
> Yes, the ac runs constantly, it is Florida.
> 
> Can anybody think of a good reason for this?


Here is a crazy idea, how about doing some actual testing? FOP or DLRO across connections and the breaker conatcts.


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## macmikeman (Jan 23, 2007)

Breakers like that usually cost about $15 bucks. I would try swapping the breaker to see if the next one heats up also. Fwiw if a breaker ever gets water in it (like if it was transported in the back of a pickup truck thru a rain) and is put into service later, that symptom is usually what results.


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## electricalperson (Jan 11, 2008)

i didnt read rest of the posts just going to post mine real quick (going out for dinner <3)

your breaker has a bad connection inside. do a FOP test with a millivolt meter across the phase. you will measure voltage drop across the contacts. some people go by a number but i like to compare readings to other breakers in the panel.

usually if its over 30 mV it might need to be replaced. i have a gut feeling that you will read somewhere in the hundreds of millivolts.

all thats needed to fix it is replace the breaker and thats it. 

loose connections cause heat when the circuit conductors are lightly loaded. 

with an infared thermometer 20 degrees above ambient tempature is a heavy load. if you have 50 degrees above ambient that means you have a loose connection. 

when you replace make sure you properly torque down the lugs with a torque wrench or torque screwdriver


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## steelersman (Mar 15, 2009)

electricalperson said:


> when you replace make sure you properly torque down the lugs with a torque wrench or torque screwdriver


Now that I must say is going a little overboard with the procedure. Talk about overkill. Torqueing isn't necessary. Especially in a house.:thumbsup:


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## electricalperson (Jan 11, 2008)

steelersman said:


> Now that I must say is going a little overboard with the procedure. Talk about overkill. Torqueing isn't necessary. Especially in a house.:thumbsup:


the NEC requires products to be installed per UL standards. torquing down conductors is part of the UL listing therefore required by the NEC. theres an FPN note in article 110 that says many terminations have a torque spec or something like that. open the code book and look for yourself


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## steelersman (Mar 15, 2009)

nolabama said:


> those are sorta stab-on not stab-in


exactly. I would rather refer to a Fed Pac as a stab-in since it does just that, stabs into the bus. Whereas the others stab on. I don't even want to call them stab on cause they don't really stab at all. But hey whatever.


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## steelersman (Mar 15, 2009)

electricalperson said:


> the NEC requires products to be installed per UL standards. torquing down conductors is part of the UL listing therefore required by the NEC. theres an FPN note in article 110 that says many terminations have a torque spec or something like that. open the code book and look for yourself


 
I believe you. I just feel that it's going overboard. I've never even seen a torque screwdriver, let alone used one or owned one.


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