Breaker playing games!!

[LarryFine]

4 no -I was mistaken-I contacted my electrician & he stated that unfortunately the customers maintenance electricians, who were on site at the time of the repair had exercised the breaker while my electrician was installing the replacement. He did not have a chance to verify resistance across B nor did he check continuity while it was faulted. I had asked that the breaker be left in its exact condition so we could present it to our vendor with the fault but things happen all too quickly in the field.

Did anybody even try manually cycling the breaker in place, before deciding to replace it?

 

[zog]

We thought the same thing but there was no indication of metal discoloration from excessive heat at the lugs or bus connections. We opened the case of the breaker and found no loose parts/debris and again no discoloration of contacts.
The B phase did have loads on it that were operating, which I would think would cause some sort of low resistance heating at the loose/bad connection. If B had never operated at all I would be on the same page with you. I am not dismissing operator error but I am not sure it was that simple.

In that case I am stumped, if it wasnt the connections no telling what it was without the breaker in our shop. Please let us know what the ETI lab says.

 

[CaliforniaElectricCo.]

In that case I am stumped, if it wasnt the connections no telling what it was without the breaker in our shop. Please let us know what the ETI lab says.

They say its fine- I joked with the guy from Emmerson & asked if he would put it in their building. He said officially no comment- technically it passed their test, I could send it to their forensics lab which would cost a small fortune. I think we have lost enough $$$ on this one already.

 

[CaliforniaElectricCo.]

Did anybody even try manually cycling the breaker in place, before deciding to replace it?

These type of intermittent problems are always a nightmare. We could have cycled it & found the problem went away---buuuutttt-- the customer was standing there with 2 of their maintenance electricians ready to swap it out. We have a hard time giving a guaranty that the issue (especially when we don't even comprehend the issue), would not occur again, when it could potentially cause a more critical loss. Luckily the phase their main network switch was on didn't go out. We were able to schedule a shutdown after hours and have their IT dept. bring down the network without incidence. The point is a breaker should never lose a single phase without tripping the entire circuit as it is intended to do for protection. If this had been a 3 phase motor load we might be replacing a single phased motor as well.

Breakers should trip all poles simultaneously, I don't like these ghost poles (thats my new technical term for this)!!!

 

[CaliforniaElectricCo.]

We had a similar thing happen to a newer 3p 200 amp CH breaker in an Allen Bradley MCC. Breaker fed a 200 amp fused disco which fed a large air compressor. Load side disconnect lug burned up, so we replaced the lug. Turned the disco back on(breaker/line side was hot while we replaced the load side lug) and checked power, we had 2 out of 3 phases(I think it might of been B phase too). Went to the MCC and shut the CH breaker off(it wasn't tripped), reset it and had 3 phases again.:-? That was odd....

Was it a KD style CB?

 

[brian john]

We had 3 CH CB's have the B phase line side bus fall off appeared the connection to the stationary contact was mis-crimped.

CH/Eaton/Westinghouse sent out a paper several years ago stating they would no no longer accept Ductor/micro-ohm readings as a pass fail but needed FOP readings at 80% (from a weal memory)

 

[zog]

We had 3 CH CB's have the B phase line side bus fall off appeared the connection to the stationary contact was mis-crimped.

CH/Eaton/Westinghouse sent out a paper several years ago stating they would no no longer accept Ductor/micro-ohm readings as a pass fail but needed FOP readings at 80% (from a weal memory)

Well thats just silly, A DC Ductor/micro-ohm test is a more accurate test than a mV drop test, we have done the research on that and purblished the paper.

 

[zog]

These type of intermittent problems are always a nightmare. We could have cycled it & found the problem went away---buuuutttt-- the customer was standing there with 2 of their maintenance electricians ready to swap it out. We have a hard time giving a guaranty that the issue (especially when we don't even comprehend the issue), would not occur again, when it could potentially cause a more critical loss. Luckily the phase their main network switch was on didn't go out. We were able to schedule a shutdown after hours and have their IT dept. bring down the network without incidence. The point is a breaker should never lose a single phase without tripping the entire circuit as it is intended to do for protection. If this had been a 3 phase motor load we might be replacing a single phased motor as well.

Breakers should trip all poles simultaneously, I don't like these ghost poles (thats my new technical term for this)!!!

Ghost poles, I like that. LOL! Still think it was a bad connection.

 

[K8MHZ]

Re-mod. Home had CH panel. We pulled new wire everywhere possible. Went to fire up the panel so we could have lights. Basement lights come on...cool. Main level now illumated...cool. Click on 15 amp breaker not labled and all the lights in the house dim out rad like. I opened the breaker back up and lights came back on. Has boss type come down with meter to see what was up. I was suspecting a bad connection somewhere. Meter connected, breaker closed, darkness prevailed and boss type reads '115.4'. No, I want amps, not volts. "That was amps" he said as I rushed to open the breaker. It seems there was a dead short in an outside light and the only resistance was in the wires which created a real nice heating element out of conductors.

I know of an inspector that has 1/2 inch burned off a pocket knife when he went L-N on a 120V 15A circuit and the breaker never tripped. It was a CH about 15 feet from the outlet being repaired.

Back in the day, CH was top of the line. I wonder what happened....

 

[hillbilly1]

Back in the day, CH was top of the line. I wonder what happened....

Westinghouse happened.