awesome!

Working on Boeing Aircraft they used nickel plated wire with teflon insulation in the fuel tanks. The ends used crimp-terminals. They usually do not need sealant over the terminals but that would help protect them from corrosion. Make sure the wiring is well supported in insulated clamps & that there is no chance for the wires to chafe and short out.

Also of interest, about boeing / planes, they have a device with micro membranes that will mechanically seperate nitrogen from passing air, which is then pumped in the fuel tanks. Even with those insulation considerations, they still had spark issues, and needed to fill the unused tank space with N2.

The problem with the Boeings was on the 747 aircraft. The large center wing tank always empties first. When the air-conditioning units underneath the tank are left on for a long time on the ground this warms & vaporises the fuel. The ignition source comes from inside the pumps which use the fuel to cool them internally. When the pumps are left on for too-long while they are cavitating they over-heat and that causes the fuel to ignite.