On board a Navy vessel, there will be fire damage control based on four categories: Alpha, something that leaves ash like wood and paper, Bravo, liquid fuel like aviation or diesel, Charlie, a fire whose ignition and continuing combustion depends upon an electrical source, or Delta, a chemical or molecular material that after getting hot enough starts to use itself as a source of fuel and oxygen.
In this case for example, an exterior light fixture gets too much salt water condensation, it might short out the base when the salt water starts conducting the electricity instead of the bulb. The surrounding plastic materials might overheat and start burning as they melt. The first thing in damage control is to disconnect the electrical power source. Until this is done, The fire will keep reigniting itself despite copious amounts of water or extinguishing agents. On an exterior fixture on the weather decks, the fastest way to fight it is to disconnect the power and use a saltwater low velocity fog nozzle. They would not have to worry about water damage to the rest of the ship since it will just drain off into the ocean.
Should be no danger once extinguished. After action remedial inspections should include fixture, cables, raceways, and surrounding cables up to and including the disconnecting protective device (circuit breaker or fuse). Not hard to do for a trained crew. Should be nothing to worry about in this case.
If the current gets too high, the fuse or breaker should react and do an automatic disconnect. The wires are rated for the disconnect so any damage in this case should be limited to the fixture and immediate area wiring.