Corrosion test of electrical connector block

The result of exposing an electrical terminal block to salt air for a prolonged period. The real danger here isn't the obvious corrosion of the contacts, but the damage to the copper wire. Un-tinned copper wire will disintegrate in sea water. If the wire is not tinned (and it isn't in this test), there is a danger that salt water will creep in to the crimped connector and sever the connection. Sometimes it is hard to see this because the plastic insulator (red in the picture) holds the hollowed-out wire in position.