Aireal

Did you solve this issue? I am sitting with the same, but struggling to find the fault.

PV modules are a current source, but they can realistically only produce up to their rated current. Your wire gauge should be designed to carry more than that amount of current. Besides an installation error I don't see a situation where, on a commissioned system, a fuse should ever blow. Even if your PV positive and negative were shorted together, it would still not draw more than the arrays rated current. What am I missing here? Are fuses actually necessary or are we just putting in extra protection for the sake of it?

Interesting question, I see the following as the safest: PV -> Fuses -> Isolator -> Inverter The SPD is in parallel so it doesn't fit into the chain here, but should hang off before the isolator. Otherwise if you turn off the isolator you then remove over voltage protection. The fuses should also be on the PV side of the isolator for the same reason, otherwise you remove over current protection if you isolate the panels.