Cutler Hammer Breakers Over-Heating

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ToxWat

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Location
Austin, TX
I just looked at a Cutler Hammer sub-panel that was installed about 2 years ago. The workmanship looks good. The panel is stuffed full of AFCI and GF/AFCI breakers. All of the breakers are hot, not warm, HOT. The ambient temp in the garage was 98F but the surface temperatures of all of the breakers ranged from 120F at the bottom to 170F at the top. I measured the feeder current at 3 amps on the A phase, and 6 amps on the B phase so the heat cannot be caused by excessive current. I was brought in to check the dish washer circuit which trips and won't reset. I verified the branch circuit is clear. The home owner said this is the 2nd breaker to fail. I noticed that most of the breakers with neutral pigtails were discolored where they exit the breaker frame. I know a lot of people will space out AFCI breakers because of heat, but this panel has all AFCI, GFCI, or GF/AFCI breakers except for 2 which ironically are at the bottom. I've looked to see if there has been a recall or if anyone else has experienced this and have come up empty. A penny for your thoughts?
 
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retirede

Senior Member
Location
Illinois
Ambient temp rating of your gear is likely 40 C (104 F). If it was 98 when you were there, perhaps it is seeing frequent ambient temp excursions above max rating.
 
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macmikeman

Senior Member
Location
Planet macmikeman
170 deg F. That's pushing pretty hard to be ambient or the other afci breakers..... This is connections or else overloading of the panel. We haven't even asked what the loads are yet.
 
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retirede

Senior Member
Location
Illinois
macmikeman said:
170 deg F. That's pushing pretty hard to be ambient or the other afci breakers..... This is connections or else overloading of the panel. We haven't even asked what the loads are yet.
Click to expand...

I was thinking that prolonged operation above rated ambient could cause connection deterioration resulting in the over temps seen even at lower ambients. I'll admit I am speculating.
 
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JFletcher

Senior Member
Location
Williamsburg, VA
ToxWat said:
I just looked at a Cutler Hammer sub-panel that was installed about 2 years ago. The workmanship looks good. The panel is stuffed full of AFCI and GF/AFCI breakers. All of the breakers are hot, not warm, HOT. The ambient temp in the garage was 98F but the surface temperatures of all of the breakers ranged from 120F at the bottom to 170F at the top. I measured the feeder current at 3 amps on the A phase, and 6 amps on the B phase so the heat cannot be caused by excessive current. I was brought in to check the dish washer circuit which trips and won't reset. I verified the branch circuit is clear. The home owner said this is the 2nd breaker to fail. I noticed that most of the breakers with neutral pigtails were discolored where they exit the breaker frame. I know a lot of people will space out AFCI breakers because of heat, but this panel has all AFCI, GFCI, or GF/AFCI breakers except for 2 which ironically are at the bottom. I've looked to see if there has been a recall or if anyone else has experienced this and have come up empty. A penny for your thoughts?
Click to expand...

Welcome to the forum.

Which CH breakers do you have (CH or BR)?
Are the breakers the same type as the panel?
What are your loads on the branch circuits? (I saw total was 3 and 6 per leg - what is the HO using when you're not there?)
What did the buss bars look like?
What did the breaker connections and cases look like?

170*F is almost 77*C, which is above the 75*C terminal rating of the breakers.

If I had to take a wag, with no pics and the above questions w/no answers, I'd guess the EC who installed the panel may have damaged the clips on the breakers causing poor/loose connections, coated them/the buss with something that is causing high resistance, or used breakers that got wet/corroded.

Please let us know what you find. I would have killed the panel, let it cool, then removed all breakers to check the buss bars and clips.

eta: tho the workmanship looks good, I would verify voltages L-L, L-N and L-G on both legs. An open neutral would cause voltage swings that could possibly be causing the breakers to overheat (super wag there).
 
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macmikeman

Senior Member
Location
Planet macmikeman
Are these the usual residential loads or are we a bunch of window shaker ac's packed into the panel? At this time of year in this heat I could see a panel getting hot from too much ac equipment all on at the same time trying to cool off the house.
 
T

ToxWat

Member
Location
Austin, TX
JFletcher said:
Welcome to the forum.

Which CH breakers do you have (CH or BR)?
Are the breakers the same type as the panel?
What are your loads on the branch circuits? (I saw total was 3 and 6 per leg - what is the HO using when you're not there?)
What did the buss bars look like?
What did the breaker connections and cases look like?

170*F is almost 77*C, which is above the 75*C terminal rating of the breakers.

If I had to take a wag, with no pics and the above questions w/no answers, I'd guess the EC who installed the panel may have damaged the clips on the breakers causing poor/loose connections, coated them/the buss with something that is causing high resistance, or used breakers that got wet/corroded.

Please let us know what you find. I would have killed the panel, let it cool, then removed all breakers to check the buss bars and clips.

eta: tho the workmanship looks good, I would verify voltages L-L, L-N and L-G on both legs. An open neutral would cause voltage swings that could possibly be causing the breakers to overheat (super wag there).
Click to expand...

This is a type CH load center. It is a sub-panel with all 120V loads. This installation is approximately 2 years old & the breakers match the panel. I took the feeder measurements when I was there. I only removed 1 breaker. The clip felt tight and the bus bar was clean. There were no signs of over-spray in the panel. I measured all voltages as correct and Both small appliance circuit breakers tripped when ground fault tested.

I am going back over there today to take some IR photos and possibly put some telemetry in place to look at power, power factor, and distortion.
 
S

ssynoground

Member
Location
Pensacola, Florida
Just ran into nearly the same exact issue. The install was about 14 months ago. Plug-on dual purpose CAF/GF breakers, 26 total. I was brought in because the garage breaker had tripped and wouldn’t reset. Ambient temp was 92F and the breakers were topping 126F, very hot to the touch. Neutral wires all discolored. Inspected all connections and all is proper. Is this a manufacturer warranty issue? I’ve ran into issues before with bad Cutler Hammer CH type GFCI breakers right out of the box. BTW, amp reading at the Main Lugs, 3 amps. Breakers are way too hot. I checked all connections even in the main outdoor panel. Bonded and greased.
 
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