Really good look at troubleshooting a solar power system problem, how it was fixed. Look at the comments. They are often informed and highlight why this problem happened in the first place: too much amperage going through the wire because solar panels connected in parallel. Parallel connection yields high amperage. Series connection yields high voltage. Normally, w/ MPPT charge controller, high voltage is desired. But this owner didn't want that for some reason I can't recall, but which he states in comments.