I have had this problem many times on different systems, but this one is happening every day. I have installed a system for a customer that consists of 8 REC 250w 60 cell panels, 4 series, 2 parallel into a classic 150. The panels have around 8.9a ISC and call for a 15a series fuse. I have an MNPV3 installed at the panels with 2 MNEPV15 breakers as a disconnect, the breakers are tripping everyday, first one, then the other. I thought these breakers were rated for 100% duty. I have had nuisance trips on other similar systems, but this one is particularly bad.
Call our tech support. We have seen some breakers lately that are doing this. We are trying to get to the bottom of it, but it is hard to when we don't get the faulty breakers back. Tech support will ship out new breakers today if you get to them. Make sure they give you a call tag so we can get the breakers back. This is very important.
360-403-7207
Please email me directly ryan@midnitesolar.com and I will get you some replacements
Ryan