Tripping Main Breakers
- Thread starter SKOEHLER
- Start date
- Status
- Location
- Massachusetts
It's a sign of a bad RTU. :smile:
My guess is no one has ever properly set the GFP protection or other settings on the main breaker.
My guess is no one has ever properly set the GFP protection or other settings on the main breaker.
zog
Senior Member
- Location
- Charlotte, NC
I agree, most likely wrong setting, "All at max" is a red flag.
Could be the breaker, testing would prove that, but in this case I think wrong settings is the culprit.
Could be the breaker, testing would prove that, but in this case I think wrong settings is the culprit.
quogueelectric
Senior Member
- Location
- new york
Open all j boxes
Open all j boxes
And control panels and look for signs of burning or explosion. It is probably a bugnut blown out Overcurrent tripping the 90 and ground fault tripping the main. So look for a short on 1 leg to ground. Look for signs of discoloration in the sealtite I have seen where a ground was never pulled and it turned the grey sealtite black melting the feeder cables when I opened the disconnect and saw the insulation melted all the way down to the steel bushing still energized I nearly soiled myself. It melted the wire so badly to the inside of the pipe that I snaped a 1inch rope in a live gear and nearly soiled myself again. This was a long time ago young and stupid now I will just schedule a shutdown on Saturday for some more overtime.
Open all j boxes
And control panels and look for signs of burning or explosion. It is probably a bugnut blown out Overcurrent tripping the 90 and ground fault tripping the main. So look for a short on 1 leg to ground. Look for signs of discoloration in the sealtite I have seen where a ground was never pulled and it turned the grey sealtite black melting the feeder cables when I opened the disconnect and saw the insulation melted all the way down to the steel bushing still energized I nearly soiled myself. It melted the wire so badly to the inside of the pipe that I snaped a 1inch rope in a live gear and nearly soiled myself again. This was a long time ago young and stupid now I will just schedule a shutdown on Saturday for some more overtime.
zog
Senior Member
- Location
- Charlotte, NC
No, GF is a different setting and has an inverse time charteristic. Post exactly what type of breaker and trip unit you have with all of the settings, and I can explain more.
brian john
Senior Member
- Location
- Leesburg, VA
1. Is this 480/277?
2. Is there GFP?
3. Is the GFP in the CB or separate?
4. Has the GFP been tested?
5. Has the CB been tested?
6. What are the ranges and setting on the Main CB?
7. Has anyone measured for grounds current at the main neutral bond connection?
8. You reset a 1200 AMP CB without knowing why it tripped BIG NO NO.
GFP=Ground Fault Protection
2. Is there GFP?
3. Is the GFP in the CB or separate?
4. Has the GFP been tested?
5. Has the CB been tested?
6. What are the ranges and setting on the Main CB?
7. Has anyone measured for grounds current at the main neutral bond connection?
8. You reset a 1200 AMP CB without knowing why it tripped BIG NO NO.
GFP=Ground Fault Protection
charlie tuna
Senior Member
- Location
- Florida
any body ever heard of a data logger??? it will take all the guess work out of the problem without damaging other equipment or possibly killing someone???
mdshunk
Senior Member
- Location
- Right here.
Amen, Charlie. Thank you for that.charlie tuna said:
Crikey!SKOEHLER said:
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
According to the GE website
http://www.geindustrial.com/catalog/buylog/03_BL.pdf#search='Skhb36bd1200'
the breaker has long time, short time, instantaneous and Ground fault functions.
I would also guess that the settings are incorrect or there is a neutral sensor where it shouldn't be.
http://www.geindustrial.com/catalog/buylog/03_BL.pdf#search='Skhb36bd1200'
the breaker has long time, short time, instantaneous and Ground fault functions.
I would also guess that the settings are incorrect or there is a neutral sensor where it shouldn't be.
1. YESbrian john said:
2. YES
3. IN THE CB
4. NO
5. NO
6. DON'T KNOW
7. NO
8. I KEPT RESETTING THE MCB TILLTHE SMOKE STOPPED AND IT FINALLY HELD. (JUST JOKIN). 1ST PRIORITY IS TO MAKE $ FOR MY COMPANY. 2ND IS TO DO SO AS SAFE IS POSSIBLE. NEITHER OF WHICH CAN BE DONE IF AN EMPLOYEE OF THE CUSTOMER RESETS THE CB 3 TIMES. TO ANSWER THIS ? NO I DID NOT RESET A 1200A MAIN BRAKER.
brian john
Senior Member
- Location
- Leesburg, VA
NO your first priority is safety I have completed several investigations were the electricians doing the EXACT same procedure was severely injured and 2 cases WORSE. A little bit of time doing proper investigation will save you from injury and possible death and how much money does the company lose if the gear vaporizes.
Believe me the average manager that was screaming get the power on will not stand behind should someone get hurt. "While he said he knew what he was doing.
As for power analyzer we use them all the time, but usually after we are at a point we cannot make a determination of what is the issue. Most times with proper investigative technique the cause of tripping can be located.
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