hbendillo
Senior Member
- Location
- South carolina
Our company received a telephone call from the owner to resolve some issues brought up by the electrical inspector regarding the electrical service for one of our projects. I was not involved in the original design for the project but after review of the drawings and speaking with the power company we have the following:
A new three-phase 480-volt electrical service was added for the building. The existing service, 208-volt three-phase, remains. The new service was added to feed two new elevators added to the building.
Service Drop: Overhead service drop from a pole mounted, open delta, transformer bank; 3-#1/0 with messenger/neutral cable. Messenger cable tied off to the building and the three phase conductors brought down to the meter through service head and conduit. So no neutral to the service equipment.
New Service: Meter and 200 amp service rated disconnect on outside wall. Conductors from meter to disconnect and then inside to wiring trough in main electrical room: 3-#3/0 & #6 G.
Inspector thinks the ground wire should be a #4.
My take is that the grounding electrode conductor should be sized #4 (These are all copper wire sizes), for meter and service disconnect. Anything past the service disconnect should be sized according to 250-66 which would be #6. The ground wire from the meter to the service disconnect should probably be #4.
This service is strictly providing the three-phase circuits for the two elevators and nothing else.
I have never designed an electrical service to a commercial building without a neutral. I'd like some opinions on the setup for the service and any other issues that I may be overlooking.
A new three-phase 480-volt electrical service was added for the building. The existing service, 208-volt three-phase, remains. The new service was added to feed two new elevators added to the building.
Service Drop: Overhead service drop from a pole mounted, open delta, transformer bank; 3-#1/0 with messenger/neutral cable. Messenger cable tied off to the building and the three phase conductors brought down to the meter through service head and conduit. So no neutral to the service equipment.
New Service: Meter and 200 amp service rated disconnect on outside wall. Conductors from meter to disconnect and then inside to wiring trough in main electrical room: 3-#3/0 & #6 G.
Inspector thinks the ground wire should be a #4.
My take is that the grounding electrode conductor should be sized #4 (These are all copper wire sizes), for meter and service disconnect. Anything past the service disconnect should be sized according to 250-66 which would be #6. The ground wire from the meter to the service disconnect should probably be #4.
This service is strictly providing the three-phase circuits for the two elevators and nothing else.
I have never designed an electrical service to a commercial building without a neutral. I'd like some opinions on the setup for the service and any other issues that I may be overlooking.