There is an industrial building with a 480V open delta service. Is it common to run 3 phase, without an Equipment ground? I had an electrical engineer tell me the equipment ground is not needed because if a leg hits ground, it would not trip the breaker until a second phase also grounds out. The situation is a cable tray with just the 3 phase conductors in it, and then conduit will be ran to a 200 amp disconnect.
The NEC wants us to run equipment grounds in all systems, right?
Is it a poor design, not to have an Equipment ground?
Thanks - SJT
