bad breakers?

[ODonnell]

I have installed and and tested a total of 8 three phase 30A/208 breakers in an attempt to find a good one. In every case the same leg on each breaker seems to be staying open. For example, I can install the breaker in the ON position. When I install it and check continuity it seems fine. If I then turn off the breaker and back on again, this particular leg on every one of these 8 breakers does not close. If I then loosen the bus screw of that leg you can hear an audible click and it is then closed. This would cause me concern that I had stumbled across a bad breaker and I would want a new one. But 7 of 7, and the one from a completely different batch??
I am currently in contact with the vendor whom i have forwarded a video. He is trying to push it up the ladder as I have an additional 5 more breakers that I have not tried (nor do I even want to, given the 8 of 8 fails, including a separate from the rest given for me to try by the vendor off their shelf, the rest being shipped new from Square D).
Anything like this ever happened to anyone that reads this? I cannot see how we are installing anything wrong. Seems to me it is a no-brainer, but if I m the one with no brain, so be it, as long as I get the job done correctly!

 

[kwired]

Maybe a defect in the bus that causes undesired pulling/twisting on the supply side link when the attachment screw is tightened?

Have you tried these breakers in a different position or even a different panel?

 

[Cow]

Maybe a defect in the bus that causes undesired pulling/twisting on the supply side link when the attachment screw is tightened?

Have you tried these breakers in a different position or even a different panel?

That's immediately what I thought as well. I've never had the issue the OP is having, definitely sounds like an odd one though.

 

[ODonnell]

UPDATE:
I had a 30A 3-ph breaker on my shelf I had forgotten about. We put that in this morning and it works fine.
I had these breakers failing in this way, on the same leg of the breaker no matter which side of the panel it was installed in and the torque specs were followed as well.
I am betting it is not too common but we go ahead and torque everything to spec when installing panels, recepts, etc.
I have contacted the vendor again and he has spoken with the square D rep and forwarded the video. His opinion seems to indicate he thinks there is something wrong with the breakers.

 

[ODonnell]

UPDATE#2
Vendor confirmed with Schneider Corp factory they know they have an issue with these. seems it may be a gapping issue within the breaker that is affected by the screw tightening.
They are arranging to replace all 12 of my breakers.
Thanks for the input.

 

[templdl]

I have installed and and tested a total of 8 three phase 30A/208 breakers in an attempt to find a good one. In every case the same leg on each breaker seems to be staying open. For example, I can install the breaker in the ON position. When I install it and check continuity it seems fine. If I then turn off the breaker and back on again, this particular leg on every one of these 8 breakers does not close. If I then loosen the bus screw of that leg you can hear an audible click and it is then closed. This would cause me concern that I had stumbled across a bad breaker and I would want a new one. But 7 of 7, and the one from a completely different batch??
I am currently in contact with the vendor whom i have forwarded a video. He is trying to push it up the ladder as I have an additional 5 more breakers that I have not tried (nor do I even want to, given the 8 of 8 fails, including a separate from the rest given for me to try by the vendor off their shelf, the rest being shipped new from Square D).
Anything like this ever happened to anyone that reads this? I cannot see how we are installing anything wrong. Seems to me it is a no-brainer, but if I m the one with no brain, so be it, as long as I get the job done correctly!

I may have missed the fact that you did test the breakers per NEMA AB4 for field testing breakers and that the breakers were tested at full voltage under load and not simply measuring contact resistance alone which is not a valid contact test.
I also understand that you did check the L-N and the L-L-L voltages at the load end of the breakers while the breakers were under load. Did you aslsone test the lne to load voltages on each pole while the breaker was under load?
Since the contacts moving contacts of a break actually rubs slightly against the stationary contact when closing if you simply measure the contact resistance each will be different and will change every time you open and close the breaker and is not a lagitimate test of the health of a breaker. A contacts that do not make good contact with one another under a load will heat often weakening the moving contact spring which results in further contact failure where the contacts fail and arc.
In my tenure in electrical OEM sale in the thousands of breakers that I felt with I ran across one breaker were they missed to bond a moving contact at the end of the contact arm. I haven't a clue as to how it got through testing and into the field.
I have ran across timem when the flexible connection between the moving contact and the trip unit failed because of bond had failed.
Also, I am assuming that the breakers in question are smaller 100 or 150a frame breakers without individual trip units. (With individual trip units they are fastened in place with 2 screws per phase.) As such the current travels through the thermal element located between the moving contact and the load end terminals of which have bonded conductor connections could fail although very unusual.
But multiple breakers failing??

 

[ODonnell]

I may have missed the fact that you did test the breakers per NEMA AB4 for field testing breakers and that the breakers were tested at full voltage under load and not simply measuring contact resistance alone which is not a valid contact test.
I also understand that you did check the L-N and the L-L-L voltages at the load end of the breakers while the breakers were under load. Did you aslsone test the lne to load voltages on each pole while the breaker was under load?
Since the contacts moving contacts of a break actually rubs slightly against the stationary contact when closing if you simply measure the contact resistance each will be different and will change every time you open and close the breaker and is not a lagitimate test of the health of a breaker. A contacts that do not make good contact with one another under a load will heat often weakening the moving contact spring which results in further contact failure where the contacts fail and arc.
In my tenure in electrical OEM sale in the thousands of breakers that I felt with I ran across one breaker were they missed to bond a moving contact at the end of the contact arm. I haven't a clue as to how it got through testing and into the field.
I have ran across timem when the flexible connection between the moving contact and the trip unit failed because of bond had failed.
Also, I am assuming that the breakers in question are smaller 100 or 150a frame breakers without individual trip units. (With individual trip units they are fastened in place with 2 screws per phase.) As such the current travels through the thermal element located between the moving contact and the load end terminals of which have bonded conductor connections could fail although very unusual.
But multiple breakers failing??

I downloaded that NEMA guideline. Interesting. I could maybe pull off a 24V 30A test for breaker trip current. Most of the other does not apply (assuming the guideline is for maintenance testing purposes, not new). Basically I get to a physical test in this procedure:

The breaker should be replaced if:
a. The contacts are not open with the breaker in the tripped or OFF position
b. The contacts are not closed with the breaker in the ON position

AND stop reading after b

Also as I stated above Schneider Corp recognizes they have an issue. Working on getting different ones (new?)

 

[Sierrasparky]

UPDATE#2
Vendor confirmed with Schneider Corp factory they know they have an issue with these. seems it may be a gapping issue within the breaker that is affected by the screw tightening.
They are arranging to replace all 12 of my breakers.
Thanks for the input.

I wonder how many damaged pieces of equipment have occurred that did not have phase protection.

 

[templdl]

I downloaded that NEMA guideline. Interesting. I could maybe pull off a 24V 30A test for breaker trip current. Most of the other does not apply (assuming the guideline is for maintenance testing purposes, not new). Basically I get to a physical test in this procedure:

The breaker should be replaced if:
a. The contacts are not open with the breaker in the tripped or OFF position
b. The contacts are not closed with the breaker in the ON position

AND stop reading after b

Also as I stated above Schneider Corp recognizes they have an issue. Working on getting different ones (new?)

Schneider is one of the leading manufacturers of MCCBs and it would sdurprize me if there had an issue of this magnitude. Having a breaker slip by final test would be rare but never the less possible. But numerous breakers provided to the game user is suspect. I would like to think that if this was isolated there would be more complaint out there.
The contacts are openned and using a common bare with each moving contact having its own spring to hold the moving contact against the stationary contact below. I have directed mony breakers for cause a failure over the years and have had the opportunity to work at a warranty return test bench as well as knowing the manager of that department well to a point where he would ship out a 600a 400a breaker as a replacement for one that is out of warranty at no charge.
I would have found you issue a personal challenge and could have gotten one of your breakers directly to the test bench for evaluation.

 

[templdl]

Schneider is one of the leading manufacturers of MCCBs and it would surprize me if there had an issue of this magnitude. Having a breaker slip by final test would be rare but never the less possible. But numerous breakers provided to the same user is suspect. I would like to think that if this was isolated there would be more complaints out there.
The contacts are openned and using a common bar with each moving contact having its own spring to hold the moving contact against the stationary contact below. I have disected many breakers for cause a failure over the years and have had the opportunity to work at a warranty return test bench as well as knowing the manager of that department well to a point where he would ship out a 400a frame 400at breaker as a replacement for one that is out of warranty at no charge.
I would have found your issue a personal challenge and could have gotten one of your breakers directly to the test bench for evaluation at my product warrant center.
Have a deep respect for the Scheider products as there were a formidable and seious competitor of mine at that time.

 

[ODonnell]

I wonder how many damaged pieces of equipment have occurred that did not have phase protection.

None. No equipment was connected. This was all new stuff. The find of the missing phase was when we went to test the recepts we installed.
All I can say is what the vendor has told me regarding the replacement of the breakers by Schneider Corp. They know they have an issue, specifically with QOB 250V 30A 3-ph breakers.
We are installing 100 Amp mains for sub panels QOB. When he brought that up they said the problem is ONLY with the 30A breakers. Tested the 100A out in a panel and verified working fine.
Loaded the 30A 3-ph I had on the shelf for another project that works fine and had no issues with it in the place of where the other had been installed.
I agree this seems a difficult scenario to accept from Square-D, but if you think about it, if installed and gotten to work once, it is not too likely anyone would check again. Perhaps the only way anyone may ever find out they had a bad breaker would be if it tripped and they tries to reset it or if they had to turn it off and it would not reset. How many years might that be down the line? They they may just replace the breaker and never think twice about it.
Then again, how many installs are going to be done that require 12- 30A 3-ph circuits and get a supply of bad breakers? Maybe this is the tip of the iceberg... maybe it is isolated, but known.
All I care about is getting my breakers replaced so I can finish the job.