Where does this electrical box go?

mine was a 100% stock harness in great shape. No visible corrosion, grime etc in the bulkhead connector. The charge wire connection got hot enough to deform it's socket, but never got crispy...now the other end of that wire, the inside the cabin portion, that wire got so hot along it's full length that it melted through it's sheathing, and welded itself into the wires around it. This energized other circuits, and basically destroyed the under dash harness. A fusible link, breaker, or fuse is a designed point of failure. Saying the engine bay side of the bulkhead connector is a designed point of failure is kind of laughable honestly. If you are going to upgrade the electrical system, it's just that, a system, upgrade the rest as necessary.
No different then upgrading your horsepower, then having the rear-end grenade, and saying it's because the transmission didn't fail like it should