HOT curcuit breakers...

[Chet]

This was a new one on me, the wife said that the hot water tank breakers had tripped. So I reset them and measured current flow, it was normal, and I checked every connection in the box to make sure they were tight. But a couple of days later the 100 amp mains tripped. HMMMM, I went to the box and the mains were so hot you could not put your finger on them for more than a second. I looked at everything that was running and it could not have been more than 50-60 amps. None of the wires were warm either. So I reset the breaker, and waited till the next morning, and the mains were still pretty warm with no appreciable load. I fired up the AC, the clothes dryer and a few lights and before long the mains were piping hot again, I measured the current at less than 50 amps. So any way, I went and bought a new set of 100's and replaced the mains, which has cured the problem. But I have never run across a breaker that got hot before....Anyone else ever have this kind of problem????

 

[B7500]

Possibly the connections of your mains to the buss were weak.
That would cause them to heat up.
-Terry

 

[Bob_Skurka]

We did at work. Our electrical contractor said he'd get one of the guys out to take care of it. But he said "In the mean time, get a fan and blow cool air at the breaker box."

I never found out the actual cause of the problem, but they simply changed out the breaker and that resolved the issue.

 

[Mark4510]

Chet,
I am no expert....just my experience from being a home owner....but I have never run into that before. We tend to lose power a couple of times a year so I check them at least that often and have never run into that.

I worked for sometime for our utility company and I have to say after that experience I am intimidated by electricity. I just call an electrician.......

 

[Chet]

Yeah, I checked that too, the slots on the breaker were quite tight, I had to use a large pair of channel locks to pull out the breaker!

 

[slowrev]

Had that problem once, Turned out to be a bad/resistive connection. Do you have aluminum wire ? It is bad to corrode and cause a resistive connection. clean and use a proper electrical "grease" to fix or avoid the problem. Thomas and Betts has some good Electrical joint compounds for this issue, just check with your electrical supply distributor. I think aluminum wire is only used for the big stuff now, like the entrance cable, or maybe the range. I put copper between the meter base and main panel, costs more but gives peace of mind.

Always be careful around electricity, when in doubt get a pro to do it. Cheaper than a burned down house or a funeral.

 

[dbelisle]

I have seen that happen all to often. You can get oxidation on the buss bar, or the internal parts of the breaker can get corroded if there not be a good bond. The resistance generates heat which causes more oxidation and makes the problem get worse. Your lucky if that's all you had to do to solve your problem. A lot of times it will burn the buss bar that you lock the breaker into and you have to change the buss bar too.

I had a Ames store that was put up in the Sixties and they had all the lighting circuits loaded more than the 80% allowed by the code. The panels had 3 inch muffin fans in the bottom 3 inch knock outs blowing air up through the panels to keep them cool enough so you could touch the breakers. I ended up changing all the breakers and the panels cooled down.

Dave in NH

 

[Chet]

Slowrev, all the wiring is copper, I ran the wires to the box myself. the house is only five years old, and there is no sign of corrosion anywhere. The breakers themselves were definetly the culprit, had heat sign all over the bottom of them, and up the sides. Although I am not a licensed residential electrician, I did work on all kinds of low and high power curcuits and equipment in the Air Force as an electrician. I most definetely respect the stuff, I have been jolted a couple of times working on aircraft, but never yet at home. It was always my own fault of course, I grounded myself out once and laid my bare arm across a terminal board another time...24 volt DC will really get your attention /forums/images/graemlins/shocked.gif

 

[KENSFM]

Just curious, what is the brand of your breaker box?
Ken /forums/images/graemlins/smile.gif

 

[To20Chris]

All you need is a little bit of contact resistance anywhere in the breaker assembly, and with that current you'll be dissipating a lot of power (heat). Check for this by measuring the voltage drop across the breaker. There better not be much, or you'll be making a lot of heat. The voltage drop across the breaker times the current flowing through it is the power dissipated. Probably just corrosion on the contacts. Is the box in a humid location?

A slightly resistive connection is one of the most dangerous situations. If there is a lot of resistance, the voltage drop will be so great that the load won't work and the current will be low, it is not as big a deal. A dead short will trip the breaker. But a little bit of resistance with a big current.......