There you can see the fuseholder in the center of that picture. It's a couple of inches off of the positive output of what ends up being a 48V pack (half LiFePO4 and half LTO). But your point is valid regarding the interconnecting wires between the parts of the pack (2AWG in this case). Any short between those wires will likely destroy their insulation and possibly ignite whatever they may come in contact with. This setup is highly experimental, nowhere near permanent, and it's back apart now.