400A Main turns off by itself

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GerryB

Senior Member
Having worked for both Sq. D and Siemens, I can attest to the fact that the breaker CANNOT move from On to Off on its own, doing so would violate NEMA design standards. Even with a shunt trip or under voltage release, the device operates the TRIP bar, so the breaker moves to the Tripped (center) position, not Off. Even the mechanical force of opening a dead short at the maximum interrupt capacity of the breaker is not allowed to over travel the handle mechanism to the full Off position. There must be a distinctly different Tripped position.

It's possible that there was a defective breaker. Siemens had a recall a decade ago on some 400A frame Sentron breakers because of a similar issue, having to do with a small plastic part in the handle that was out of spec and could break off, which could interfere with the proper handle operation, one possible outcome of which was reported to be the lack of a trip position. But 3 defective breakers with the exact same defect that Sq. D is unaware of? Not likely.

POSSIBLY there is a motor operator on this breaker that the OP is unaware of. It might be tied to some sort of energy or power quality monitoring system and when it sees something going wrong, is MOTORING the main breaker open on purpose. Something like a Sq. D Powerlink MVP system. For all we know, this could be completely normal, the OP has never reported back a part number for the breaker.
Your post is informative. I have a question unrelated (kind of) to this post. You mentioned NEMA design standards. Would they apply to Cutler Hammer tan handle breakers, which trip to the full off position? As far as I know they still do, and you don't know if it tripped or was turned off.
 

ATSman

ATSman
Location
San Francisco
Occupation
Self Employed
such a long post and may have missed it but can you (again) give the make and model# or pic
of this mystery breaker?
 
... make and model# or pic ...
Better yet: make and model# AND ALSO some pictures.

The crowd here is getting suspicious, Ride the Lightning. Help us see that you're for real. Why don't you take up Brian John on his generous offer (post #53).

(Aside from which, why on earth would you WANT to troll us? What sort of pathetic entertainment might that provide? I'd so much rather believe that you've brought us a genuine good-faith mystery. Besides, you've a chance to show the skeptics that this might actually be a problem, outside of "electrician folklore".)
 

JFletcher

Senior Member
Location
Williamsburg, VA
Better yet: make and model# AND ALSO some pictures.

The crowd here is getting suspicious, Ride the Lightning. Help us see that you're for real. Why don't you take up Brian John on his generous offer (post #53).

(Aside from which, why on earth would you WANT to troll us? What sort of pathetic entertainment might that provide? I'd so much rather believe that you've brought us a genuine good-faith mystery. Besides, you've a chance to show the skeptics that this might actually be a problem, outside of "electrician folklore".)
There are people who live to troll, to wind people up. I dont think the OP is one, however if it is a simple problem discovered, I doubt we'll hear the answer. Pride and all...
 

roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
I wonder if there's somebody that looks like this walking around the premisis.



Roger
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Your post is informative. I have a question unrelated (kind of) to this post. You mentioned NEMA design standards. Would they apply to Cutler Hammer tan handle breakers, which trip to the full off position? As far as I know they still do, and you don't know if it tripped or was turned off.
I don't know, you'd have to ask them.

But your question prompted me to look, and in doing so, I discovered that the old NEMA AB-1 I was referring to was withdrawn in 2012 in favor of UL489. I no longer have a full copy of UL489, so I'm not sure if that requirement is still there. But I have a reference on markings that need to be on UL489 listed breakers, and in that document, they word it that IF a breaker has a center "Trip" position, it needs to be marked as such. That document is not where the center trip position would be REQUIRED, but the way that was worded about the marking of it implies that it might not be.

Regardless, the Sq. D breakers I dealt with all have a center trip position. The only possibility is if it is a "Homeline" series which came out after I left.
 

kwired

Electron manager
Location
NE Nebraska
I don't know, you'd have to ask them.

But your question prompted me to look, and in doing so, I discovered that the old NEMA AB-1 I was referring to was withdrawn in 2012 in favor of UL489. I no longer have a full copy of UL489, so I'm not sure if that requirement is still there. But I have a reference on markings that need to be on UL489 listed breakers, and in that document, they word it that IF a breaker has a center "Trip" position, it needs to be marked as such. That document is not where the center trip position would be REQUIRED, but the way that was worded about the marking of it implies that it might not be.

Regardless, the Sq. D breakers I dealt with all have a center trip position. The only possibility is if it is a "Homeline" series which came out after I left.
Homelines trip to center. AFAIK their internals are/nearly are identical to QO internals but no trip indicator flag.
 
Ok folks, sorry I haven't responded in a bit, been busy at the coffee joint. The facility needs to be manned during hours of operation to get them back online after this 400A Main goes down.

No, I am not a troll. I have been in this trade for 25 years, the last 13 I have been on my own.

This property/building is owned by myself and 3 others. I have 0 desire to keep screwing around with this issue any longer then necessary as I owe my tenant a fully operational and trouble free facility.

I am indeed a new member as I am fully confident in my abilities as an electrician/landlord/father/husband etc. etc. Any help I have ever needed has always come from a phone call or google. I became a member here because both of those have now failed me and I didn't know where else to turn.

Square D 400A 3pole CB # - LAL36400MB

I had a square D tech come out to the site to look, of course he informed me it cannot happen. He then took both of the other 2 breakers I had removed and brought them to his shop to put them under a load test. Guess what? They tested fine. I am not having a load or thermal issue. The breaker goes to the off position intermittently. I do not need to turn it off then turn it on again as it does not trip, it simply turns off with no explanation. Somehow, the last 3 or 4 days I have had no trouble with single phase breakers tripping anymore, it's just the annoyance of the damn main turning off.

While the building is in full operation and with the A/c loads starting/calling, across all phases I have recorded amperages of no more then 180amps. There is no thermal build up of heat (we did use a laser heat thermometer to check this)

As of right now, we have a recording device on the meter from the power company which is due to be removed this Thursday afternoon. We are really holding out for those test results before we go ahead and move forward.

I and my crew did in fact wire this building from the ground up.
 
Ok folks, sorry I haven't responded in a bit, been busy at the coffee joint. The facility needs to be manned during hours of operation to get them back online after this 400A Main goes down.

No, I am not a troll. I have been in this trade for 25 years, the last 13 I have been on my own.

This property/building is owned by myself and 3 others. I have 0 desire to keep screwing around with this issue any longer then necessary as I owe my tenant a fully operational and trouble free facility.

I am indeed a new member as I am fully confident in my abilities as an electrician/landlord/father/husband etc. etc. Any help I have ever needed has always come from a phone call or google. I became a member here because both of those have now failed me and I didn't know where else to turn.

Square D 400A 3pole CB # - LAL36400MB

I had a square D tech come out to the site to look, of course he informed me it cannot happen. He then took both of the other 2 breakers I had removed and brought them to his shop to put them under a load test. Guess what? They tested fine. I am not having a load or thermal issue. The breaker goes to the off position intermittently. I do not need to turn it off then turn it on again as it does not trip, it simply turns off with no explanation. Somehow, the last 3 or 4 days I have had no trouble with single phase breakers tripping anymore, it's just the annoyance of the damn main turning off.

While the building is in full operation and with the A/c loads starting/calling, across all phases I have recorded amperages of no more then 180amps. There is no thermal build up of heat (we did use a laser heat thermometer to check this)

As of right now, we have a recording device on the meter from the power company which is due to be removed this Thursday afternoon. We are really holding out for those test results before we go ahead and move forward.

I and my crew did in fact wire this building from the ground up.
Please keep us informed as what you are describing is pretty strange. Hence, of course, the levity about ghosts and stuff.

But seriously, I don't think you will find a better team than here on this forum to help you solve really strange problems. The 'team' gets better when a strange one is solved and the solution gets posted.

I sure want to know what's going on. I have been at this kind of stuff for years and have never seen a breaker turn all the way off by itself. I am the kind of person that tears breakers apart to see how they work. Fuses, too, for that matter.

You dilemma has got my curiosity stoked.
 
Please keep us informed as what you are describing is pretty strange. Hence, of course, the levity about ghosts and stuff.But seriously, I don't think you will find a better team than here on this forum to help you solve really strange problems. The 'team' gets better when a strange one is solved and the solution gets posted.I sure want to know what's going on. I have been at this kind of stuff for years and have never seen a breaker turn all the way off by itself. I am the kind of person that tears breakers apart to see how they work. Fuses, too, for that matter.You dilemma has got my curiosity stoked.
I intend to share anything I find. As this is such a unique situation, any findings/suggestions can only help us all in the future. Thank you.
 
Ride the Lightning,

Is there any way you can set up a video camera and get a video recording of the breaker turning off? Most decent digital pocket cameras have pretty good video quality.

A video, for one thing, will prove that what many experts say can't happen is indeed happening. Also, at 30 fps, a frame by frame analysis may show something that is escaping the human eye.

Make sure the sound is on. Maybe there is something physical, not electrically related, going on at the same instant the breaker shuts down....hopefully it makes noise and can be captured on the video.

The video may also reveal the motion of the handle as the breaker shuts off. It may answer questions like, how fast did the handle move? Did it vibrate or hesitate in any manner? Did the handle move on it's own at all prior to shutting down?

In a way, I wish I worked for you. Solving problems like yours is interesting to the point of being fun for me. When others get frustrated beyond belief, I am just starting to get intrigued.
 
Ride the Lightning,

Is there any way you can set up a video camera and get a video recording of the breaker turning off? Most decent digital pocket cameras have pretty good video quality.

A video, for one thing, will prove that what many experts say can't happen is indeed happening. Also, at 30 fps, a frame by frame analysis may show something that is escaping the human eye.

Make sure the sound is on. Maybe there is something physical, not electrically related, going on at the same instant the breaker shuts down....hopefully it makes noise and can be captured on the video.

The video may also reveal the motion of the handle as the breaker shuts off. It may answer questions like, how fast did the handle move? Did it vibrate or hesitate in any manner? Did the handle move on it's own at all prior to shutting down?

In a way, I wish I worked for you. Solving problems like yours is interesting to the point of being fun for me. When others get frustrated beyond belief, I am just starting to get intrigued.
Lol. I so wish I shared your optimism! But going on almost 2 weeks of this has put a damper on my thirst for identifying a problem. I should be getting a camera today or tomorrow as its long overdue for my own sanity. We did capture it once thru the store security camera but I do not have that recording.
 

mgookin

Senior Member
Location
Fort Myers, FL
+1 on the video. And since rogue humans have been ruled out, it does not have to be covert. That means you can use a higher quality system.

If this follows another event (I think you said some branch breakers trip prior to main OCPD turning off) maybe you could piece together a logic circuit to activate it? Of course it needs to be battery powered which you may be able to do with a UPS from your office.
 
+1 on the video. And since rogue humans have been ruled out, it does not have to be covert. That means you can use a higher quality system.

If this follows another event (I think you said some branch breakers trip prior to main OCPD turning off) maybe you could piece together a logic circuit to activate it? Of course it needs to be battery powered which you may be able to do with a UPS from your office.
All 120v gfi cb's have been replaced with normal breakers and gfi devices have been installed where necessary. Since then no breakers or gfi receptacles have tripped. It's just the sporatic nature of the main turning off.
 
RtL, thanks for so graciously responding to the skepticism here. And for your explicit promise to keep us informed.

Is there any feasible way to (or valid reason to) monitor electromagnetic or seismic activity at the panel? Is there anything interesting installed behind (let alone mounted on) the panel's wall?

Is it a useful clue, that you cured the single-phase tripping by removing the GFCI breakers?

I doubt this is going to helpl, but here's the closest thing I found to specs on that main breaker:
https://images.tradeservice.com/HifzUoRllNx6tNO8/ATTACHMENTS/DIR100077/SQAREDE61565_78_79.pdf

The "MB" suffix apparently means only that's it's the short-handled version.

And here's a catalog. Would the Mag-Gard variation (p. 3-10) be indicated for this shop's equipment?
https://s3.amazonaws.com/cesco-content/unilog/Batch4/785901/101225-Catalog.pdf

I'm hopelessly intrigued by this mystery, but entirely sympathetic to your frustration. Good luck!
 
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