Popped panel breaker?

Re: Popped panel breaker?

arby wrote: »

Hello,
There was a very severe rainstorm this past weekend when I wasn't at the cottage.
I noticed quite low amps coming in on the Trimetric and the MX60. I went to the pole mount and found one breaker of two had popped.
What might cause that?
TIA, RB

I'm assuming this "one breaker" is one breaker of X number of breakers in your combiner box? If not, what circuit does this breaker protect / serve?

If there is a cover, did you remove it and inspect to see if rain had gotten inside and caused a short somehow?

Re: Popped panel breaker?

arby wrote: »

There are two breakers inside an MS combiner box. No, I did not look deeper. I just turned it back on and it stayed on.
I wondered if I need to build an enclosure for the box although they look to be pretty water tight.

I have a combiner box from Midnite. It's for inside use only, though. So, you may want to check it for being watertight.

I may be wrong. But, if the enclosure has a NEMA (I believe that is what it is?) rating on it to be used in weather, it should be pretty tight. Could have been a number of different things, though. It may depend on how it was mounted. You said it was a pretty heavy storm. So, maybe the wind was blowing the rain almost sideways? Lots of variables.

Anyway, that's what I figure it was, somehow rain shorted the breaker some how. You were able to reset it because it had dried out already, perhaps.

I would check and make sure no rain can be blown across the box, possibly entering it through any sort of small opening in the box. That's probably all it was.

Problem is, the sun would have had to be out during the time it was raining - something my dad used to say, "The Devil is beating his wife," when weather is like that.

Re: Popped panel breaker?

ILFE wrote: »

I have a combiner box from Midnite. It's for inside use only, though. So, you may want to check it for being watertight.

What product labeled "combiner" does Midnite make that is not NEMA rated? Did you take an indoor box and wire it up to be a combiner?

By the way, there are different levels of NEMA rating. Most/many NEMA rated boxes are not literally watertight.

--vtMaps

Re: Popped panel breaker?

What voltages are involved at and around the breaker that tripped? If the voltage is high enough, moisture could allow the initiation of arcing that might produce enough heat to trip the breaker.
How long have the breakers been out there in the elements? Reason asking, I've seen breakers used in an unheated building where dampness resulted in internal rust and corrosion, increasing the resistance at the breaker's internal contacts to the point where the contacts would build up enough heat to trip the breaker at far below the rated amperage. (broke them apart after taking out of service to see what was the problem)
I suspect a breaker problem as the MX60 will not normally allow battery power to reverse to the panels, and the panels themselves, if the breaker is properly sized, cannot produce enough current to trip a properly functioning breaker even if the output is shorted. If there were more than two strings, each with it's own breaker, it could be possible for one shorted string to drain the output from the other two or more strings and thus trip it's breaker, but that wouldn't happen with just two strings.
Beyond that, is it possible for a raccoon for example, trying to climb the pole, to trip the breaker while using it as a foot hold, or some other animal rubbing against the breaker?

Re: Popped panel breaker?

arby wrote: »

There are two strings wired for 72 volts. I have seen the voltage go as high as 125 in the winter but at this time of the year about 92 to 100.
Impossible for an animal to trip the breakers because they are behind a metal front cover.
I'm pretty sure they are 15 amp breakers.
They definitely are in a damp location right by a wide creek that sometimes overflows and covers the bottoms of the poles, but the box is about 6' above ground.

Could have been a baby giraffe.

Seriously, I still believe it was just wind blown rain that somehow got inside and caused the issue.