Main Breaker Trips
- Thread starter Arce2ee
- Start date
- Status
iwire said:That was not really what I was getting at, some of the posters where focusing on the breaker tripping because of inrush currents and seem to have missed the fact it was tripping more times when the utility failed.
You are correct that it only trips on loss of utility. Under normal operation the load on the building is no where near high enough to trip the breakers even with inrush currents.
zog
Senior Member
- Location
- Charlotte, NC
Arce2ee said:
First of all, I dont know anything, you havent provided enough information about the system at all, many assumptions are being made here.
Second, there is no "problem" the UV relays are doing just what they are supposed to do on a loss of utility power, they are also protecting your equipment from overloads. Now the settings may not be correct, when was the last time you had a coordination study performed?
Third, if you are going to call a field rep, call someone certified and from an independent 3rd party, but you dont need to call anyone yet because you dont even know IF you have a problem yet.
Get some info, name plate data from the breaker, any relays on the switchgear, what are the main breakers tripping on? Take some pictures of the breaker, trip unit, and overall of the switchgear and post them here.
zog
Senior Member
- Location
- Charlotte, NC
Arce2ee said:
The REAL question here is, WHY do you lose power from the utility so often?
brian john
Senior Member
- Location
- Kilmarnock, Va
- Occupation
- Retired after 52 years in the trade.
Sometimes it is mounted in a cabinet above the door or in Square D infinite wisdom in the back off the gear in any one of 2-6 sections like being on a game show.
And in a recent gear next to the live bus in the switch enclosure...
And in a recent gear next to the live bus in the switch enclosure...
POWER_PIG
Senior Member
What you need here is Super ZOG to pull up in his million dollar rig and acess the situation,,,,,,,,,this gonna be be pretty pricey Im sure.....zog said:
Oh yeah, and don't be alarmed when he finally makes it out of the truck, with full bore linear super dooper PPE on of course, looking like one of the ghost busters.....lol.....just kidding..........kinda:roll:brian john
Senior Member
- Location
- Kilmarnock, Va
- Occupation
- Retired after 52 years in the trade.
Experience, common sense, testing and NO you do not need the breaker manufacture rep. If you are unsure of what you doing locate a testing company.
zog
Senior Member
- Location
- Charlotte, NC
POWER_PIG said:What you need here is Super ZOG to pull up in his million dollar rig and acess the situation,,,,,,,,,this gonna be be pretty pricey Im sure.....
If he would just post a picture of the equipment we could probally help him here, or at least tell him what needs to be done.
Test!
Test!
I had a client that had the same problem! Their 3000A main breaker tripped. Apparently, it was when utility was restored to the building. They reset the breaker and it held.
I arrived the next day to look at it, and I noted the last date of the testing of the breaker which was 15 years earlier. I am not sure what the industry standard on testing the mains but I think it now time! I do not know why it tripped. I recommended they get this tested by a testing company.
This building goes through rigorous maintenance program of annual testing. I like to see the inferred stickers on panels. It tells me that this owner cares about the reliability of their electrical system. Apparently they missed a big item! The building engineer admitted he didn't look at the last testing date and missed it in his preventive maintenance program.
TEST TEST TEST
Test!
I had a client that had the same problem! Their 3000A main breaker tripped. Apparently, it was when utility was restored to the building. They reset the breaker and it held.
I arrived the next day to look at it, and I noted the last date of the testing of the breaker which was 15 years earlier. I am not sure what the industry standard on testing the mains but I think it now time! I do not know why it tripped. I recommended they get this tested by a testing company.
This building goes through rigorous maintenance program of annual testing. I like to see the inferred stickers on panels. It tells me that this owner cares about the reliability of their electrical system. Apparently they missed a big item! The building engineer admitted he didn't look at the last testing date and missed it in his preventive maintenance program.
TEST TEST TEST
Fixed
Fixed
Just for anyone interested in knowing what the problem was. The relay that the manufacturer provided with the breaker was designed to trip on three phase loss protection instead of single-phase loss protection like we were expecting. The relay has been changed and all is as expected.
Thanks to all with helpful replies!
Fixed
Just for anyone interested in knowing what the problem was. The relay that the manufacturer provided with the breaker was designed to trip on three phase loss protection instead of single-phase loss protection like we were expecting. The relay has been changed and all is as expected.
Thanks to all with helpful replies!
zog
Senior Member
- Location
- Charlotte, NC
Arce2ee said:
Where? Co-Op?
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I know the problem has been solved. But just for the purpose of improving our collective troubleshooting skills, I'd like to respectfully point out a subtle step that many people missed here...
In the very first post by Arce2EE:
Had the problem been a 27 release in the circuit breaker, he would NOT have been able to reset the breaker with the utility power off!
In the very first post by Arce2EE:
Had the problem been a 27 release in the circuit breaker, he would NOT have been able to reset the breaker with the utility power off!
zog
Senior Member
- Location
- Charlotte, NC
Good point, I missed that little tidbit.
- Status