Classic popping breakers

[SolarWind]

I have a client who recently upgraded to 8 panels in four strings of two (250w PV), and the web sizing tool show that a 40 amp breaker should be sufficient to handle the input to a Classic 150 on a 24v system. I supplied a 63a breaker as that is what I had available and customer says it keeps popping on bright sunny days. He’s asking me to troubleshoot this remotely as the site is nearly four hours away. I didn’t do the wiring, it was done by an electrician following my instructions (two panels in series, four strings in parallel) and there should be no issues. I don’t know if this can be the breaker, the Classic or something in the PV wiring or homerun. It's a very short home run and wiring is oversized. We had the Classic previously set up with 6 panels wired in two strings of 3 and it worked flawlessly. Any ideas appreciated.

SW

[Vic]

Hi SW,

What brand and model number is the breaker that is tripping?

Can the Electrician check that the cable connections to the breaker are Torqued TIGHT?

Poor or loose connections to breakers can cause much additional heating in the breaker,  causing it to trip.

Using standard assumptions for the PV specs,  it does seem that a 63 A MNEPV breaker should do the job without tripping.

Thanks,   Vic

[Halfcrazy]

You do not suppose the 63 amp breaker found its way on the battery side of the classic, not the pv side do you?