Help: Possible overcurrent on disconnect

[iRenaissanceMan]

My system has been working flawlessly for about 6 months. However, just recently, my solar system blew at the disconnect. I looked at my enphase app and it shows that 1 of the panels isn't producing. We had a storm recently and I'm guessing the storm cause either the microinverter, panel or wiring issues at the panel/inverter location. I haven't gone up to the roof the check. I opened the disconnect and one of the service legs to the main panel/meter is burned.

The system is a service side tap, so the wires from the disconnect tap directly to the 4/0 AL wire from the service meter.

I checked all the other wiring downstream from the disconnect --> meter --> combiner --> 8awg cu wires that go to the microinverters in the combiner box and they all look nominal. The breakers in the combiner box never tripped.

I don't fully understand solar. I was expecting if the micro/panel isn't working, that 1 micro/panel combo would simply not provide power. Also, if there was an overcurrent issue with the strings, the breaker would trip in the combiner box.

I keep staring at the disconnect and don't understand what could draw so much current to blow the fuse in the disconnect. Does it have to do with the service side tap? I figured if the load from the home was greater than what the panels could produce, the power would be drawn from the service meter/wires. Is that not the case?

Thanks for any help / education / insight on this.

 

[crossy]

I would normally say that kind of overheat damage was caused by a loose connection rather than over-current.

I'm assuming the fuse didn't pop.

 

[iRenaissanceMan]

I would normally say that kind of overheat damage was caused by a loose connection rather than over-current.

I'm assuming the fuse didn't pop.

Yes, the fuse popped. I checked the screw and connection was tight.