Shrink tubing conforms to the size and shape of wires, connections, open coils, and other electrically conductive elements to insulate and protect them from adverse environmental conditions. Heat ...

Slide the tubing over the cable before you connect the wires to the splice block. Then slide the tubing over the connector and shrink it with a heat gun (best) or a torch (gently). The other type ...

That’s particularly problematic for things like wire splices in damp environments, something that no amount of electrical tape is going to help. Heat shrink tubing might be your friend here ...