200A breaker tripped

[electrofelon]

I have a ground mount solar site with a 200A MB service panel, 120/240. Maximum possible solar back feed is about 65 amps. The main breaker was tripped a few days ago. It has only happened once. Question is what could possibly have made that breaker trip? There are no faults on the load side of that main breaker, and when we turned it back on the two inverters came back on and everything was fine. Some sort of surge from the utility? Act of god? Neutrinos? Another Chinese balloon with micro emp capability?

 

[ptonsparky]

I have a ground mount solar site with a 200A MB service panel, 120/240. Maximum possible solar back feed is about 65 amps. The main breaker was tripped a few days ago. It has only happened once. Question is what could possibly have made that breaker trip? There are no faults on the load side of that main breaker, and when we turned it back on the two inverters came back on and everything was fine. Some sort of surge from the utility? Act of god? Neutrinos? Another Chinese balloon with micro emp capability?

Excessive resistance of breaker contacts? Check FOP across the contacts.

 

[Ponchik]

Let it be and see if you can get a pattern.

if it was a surge from POCO how would it trip breaker? Just and over current condition but from the reverse?

 

[James L]

Does amperage necessarily mean heat?
It's thermally protected?

Never mind the trip amperage, what's the trip temperature? And did it get that hot?

 

[SceneryDriver]

Bad connection at the breaker lugs would create excessive heat and might cause the breaker to trip. How do the terminations look, including the FACTORY terminations? Check the factory lugs/terminations too - wouldn't be the first time someone forgot to torque something at the factory.


SceneryDriver

 

[electrofelon]

I wasn't there personally, someone just went there and reset it nothing was inspected. I did the terminations about a year ago, I am confident in those but good point on the factory terminations. This job is an hour and a half away but I will take a look next time I'm nearby.

 

[hillbilly1]

I wasn't there personally, someone just went there and reset it nothing was inspected. I did the terminations about a year ago, I am confident in those but good point on the factory terminations. This job is an hour and a half away but I will take a look next time I'm nearby.

Don’t rule out sabotage, since you didn’t reset it yourself, it may not have been tripped, but manually turned off. I had a call many years ago at a chain drug store, where they had two breakers tripping at the same time, but randomly. Couldn’t find any issues, so I put a power monitor on it. I locked the panel the monitor was on, and was sitting in my truck on a conference call. The manager came running out, and said it did it again, but only one breaker “tripped”. It was in the panel that wasn’t locked, and it was turned “off” not tripped.The breakers controlled the cash registers and lighting. We returned and installed a hidden camera. It happened again a couple of days later, turned out to be the Pharmacist turning off the breakers! He was mad they were closing that store, and moving a couple of miles down the road. Needless to say, he lost his job!

 

[James L]

Could be a simple as a defective main.
I replaced a 200a mb panel 2 weeks ago, it was only 2 years old.

I had to move it out of a basement bathroom. But the first day on the job I moved the SER above the panel and the main started sizzling inside. Lights were blinking, too.

I checked connections, bolts to buses, everything. It was something inside. 60 amps would have probably tripped it.

 

[AC\DC]

Second James idea I just did the same today.