It wasn't weatherproof! They had washed down the area, and directly sprayed the box with water. When the breaker kicked an inexperienced electrician reset the breaker witout checking what had happened. Had this been in a house, I think it would have burned to the ground. As it was in a factory and the wall was fire retardent there was no other damage. As for the switch, it melted the center. Service was from 277 and there were three switches installed. You are correct on the voltage