Breaker playing games!!

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C

CaliforniaElectricCo.

Member
So I have a customer who we recently installed a KD3150 CH breaker to feed a panel with mostly dedicated circuits for future phone systems. The customer called me and stated the breaker lost one phase and did not trip. Sure enough when we got down there the breaker while mounted to the bus had current and voltage on line side A & C and voltage on B, but only current & voltage on load side A & C. We removed the breaker and tested continuity an found A & C to be closed but B was open. The trip mechanism simply did not function. BTW we only had 20-30A on A & C ( we had previously balanced the load during installation & the customer claimed no new loads were added or modified, this coincided with our findings) this was a 150 A 3pole CB 120/208V.
We replaced the breaker in kind. I sent the breaker back to my vendor under warranty with the stipulation that testing was required to guaranty warranty. Well Emmerson tested the CB individually on each pole to the tolerances & found the trip to be fully functional in each instance. They have guaranteed it as good! The vendor has asked for payment on the testing. $250. When I asked Emmerson if they would use this breaker in their building knowing we had 5 eye witnesses verify the center pole was open while the other two were closed & the trip failed to trip, they said, no comment- technically it passed so it is technically good... how do you think our customer would respond to that! I could send it to Emmersons forensic labs for a small fee of course!

The breaker was $1200 and the customer bought a replacement for $2200. I wanted to give the customer a replacement breaker under warranty which they would be open to but now it looks as though I need to cover their cost plus the testing, and our overtime labor to swap it after hours. We stand behind our work, so we just eat it.

What really gets me is, no one can answer the question- Why did the center pole open and not trip the breaker?? How could this happen? One of life's many unanswered questions.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I have had so many problems with CH breakers I won't use them unless they are replacements. I also inform the customer of my experiences with CH breakers and I do not warranty them in any way.

CH should happily replace the breaker in question but I think I know better. Problems with their breakers have been complained about from contractors and inspectors that I know to no avail.

You are in a sticky situation. You may have to do what it takes to please the customer on this one and try to cut your losses. You will learn something from this that will likely be a pay back in the long run. Use only equipment vendors that stand behind their products and have products you have not had repeated trouble with. If the customer insists you use equipment you don't want to use make sure they know that you get paid to work on it every time it fails.
 
Rick Christopherson

Rick Christopherson

Senior Member
Was the breaker fully cycled after it was installed? The B-phase latch mechanism could have been barely hanging on the edge, and eventually let go without actually causing a trip.
 
C

CaliforniaElectricCo.

Member
I agree wholeheartedly that we need to keep the customer happy- they are our bloodline. I wouldn't even present the arguments my vendor & the testing facility have given me- it goes against reason.
My only issue now is that we spent a small fortune with no viable answers?? The curiosity is killing me!
 
zog

zog

Senior Member
Location
Charlotte, NC
CaliforniaElectricCo. said:
Well Emmerson tested the CB individually on each pole to the tolerances & found the trip to be fully functional in each instance. They have guaranteed it as good! The vendor has asked for payment on the testing. $250. When I asked Emmerson if they would use this breaker in their building knowing we had 5 eye witnesses verify the center pole was open while the other two were closed & the trip failed to trip, they said, no comment-.
Click to expand...

Did emerson do primary or seconday injection testing on the breaker? That could be the key here. Do you have a copy of the test report you can post?
 
Last edited:
C

CaliforniaElectricCo.

Member
re: cycling 100%


We are 82% - 88% probably maybe fairly certain it was.
wouldn't the other poles drop out too? It had been in operation for approx. 7 months with no instances.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
CaliforniaElectricCo. said:
I agree wholeheartedly that we need to keep the customer happy- they are our bloodline. I wouldn't even present the arguments my vendor & the testing facility have given me- it goes against reason.
My only issue now is that we spent a small fortune with no viable answers?? The curiosity is killing me!
Click to expand...

Can you get the suspect breaker and do an autopsy? Photograph each step of the disassembly as you go and if you find a visible failure use the macro feature on your camera to get the best, most detailed picture you can get.

Send copies of the pictures to all concerned. Post pics here. Let the vendors know that the story and the pics are here and give them the page address.

I suspect you will see some change on the vendor's attitude if you find damaged or missing parts and thousands of electricians can see pictures of them.
 
zog

zog

Senior Member
Location
Charlotte, NC
CaliforniaElectricCo. said:
fully cycled at installation
Click to expand...

Did Emerson do a primary or seconday injection test? Thats the key here. If they did a secondary injection test, which is commonly done as a shortcut on installed MCCB's, your breaker would have passed the trip testing and could still have had a problem on phase B. If they did primary injection that would eliminate that possibility, in which case I have some other ideas.
 
zog

zog

Senior Member
Location
Charlotte, NC
Correct me if I am wrong on the sequesnce here.

1. Breaker was recently installed, no acceptance testing done at that time.
2. Shortly after the load saw a single phase condition
3. Voltage and current were measured with the breaker installed, no V or I on phase B
4. Breaker was removed from system, someone checked across the contacts with (Ohmeter?, DLRO?) and had low resistance on phase A and C, high resistance on phase B.
5. Breaker was sent to emerson, tested fine.

This all right?
 
C

CaliforniaElectricCo.

Member
zog said:
Correct me if I am wrong on the sequesnce here.

1. Breaker was recently installed, no acceptance testing done at that time.
2. Shortly after the load saw a single phase condition
3. Voltage and current were measured with the breaker installed, no V or I on phase B
4. Breaker was removed from system, someone checked across the contacts with (Ohmeter?, DLRO?) and had low resistance on phase A and C, high resistance on phase B.
5. Breaker was sent to emerson, tested fine.

This all right?
Click to expand...

1 yes
2 yes but 7months had passed under load before first and only noted failure
3 yes
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.
5 yes
 
C

CaliforniaElectricCo.

Member
K8MHZ said:
Can you get the suspect breaker and do an autopsy? Photograph each step of the disassembly as you go and if you find a visible failure use the macro feature on your camera to get the best, most detailed picture you can get.

Send copies of the pictures to all concerned. Post pics here. Let the vendors know that the story and the pics are here and give them the page address.

I suspect you will see some change on the vendor's attitude if you find damaged or missing parts and thousands of electricians can see pictures of them.
Click to expand...

Great Idea! - It may be my only recourse- thanks!
 
zog

zog

Senior Member
Location
Charlotte, NC
CaliforniaElectricCo. said:
1 yes
2 yes but 7months had passed under load before first and only noted failure
3 yes
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.
5 yes
Click to expand...

#4 makes me lean towards the connections, not the breaker. A poor connection could have caused the loss of phase B.

All 3 phase contacts of this breaker are connected to the same jackshaft, not possible for 1 phase to be open and the other 2 closed. It is possible that a forgein object (Insulation) could have fallen between phase B contact, I have seen that happen a few times, you could open the case and look inside for any loose material but given the event in #4 above, I would bet a bad connection was the culprit here. Which leads to an installation problem and backs up the need for appectance testing.
 
C

CaliforniaElectricCo.

Member
zog said:
#4 makes me lean towards the connections, not the breaker. A poor connection could have caused the loss of phase B.

All 3 phase contacts of this breaker are connected to the same jackshaft, not possible for 1 phase to be open and the other 2 closed. It is possible that a forgein object (Insulation) could have fallen between phase B contact, I have seen that happen a few times, you could open the case and look inside for any loose material but given the event in #4 above, I would bet a bad connection was the culprit here. Which leads to an installation problem and backs up the need for appectance testing.
Click to expand...

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.
 
C

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
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....
 
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