Naval ships don't use neutrals, but use 110/63V floating delta, where both terminals in receptacles are hot. The only time the neutral terminals are actually grounded is when fed via isolation transformers or isolated UPS, but that's restricted to very particular applications and done at the equipment, not the panel. This method of distribution lowers the voltage potential (which is important when considering damage control while flooded with saltwater) and increases fault tolerance- you can short out a phase to ground and the system will still work. There are, of course, no ground wires, just bonding to the ship's hull.
So, what you see are 3-phase panels with all "1-phase" circuits fed from 2-pole breakers and ungrounded cables.
Last edited by SteveFehr; 11/27/07 07:59 AM.
