msu-ee
Member
- Location
- Columbia, MO
- Occupation
- Electrical Engineer
I have a complex grounding/generator question and would like to bounce this off some other experts.
I have a new two story building under construction.
The owner decided, during construction, they would like to add a generator to pick up all building loads.
The building was set up with three services, 208v 3 phase, 4 wire.
There are two services feeding the upper floor and one feeding the lower floor (a bank).
The bank has a 600A CT metered service with an MDP located just inside the building.
The upper floor has two tenants and thus two services.
One service is 200A and one is 400A, both fed from a meter center on the outside wall.
I would like to split this building up and supply it with two generators, for cost reasons.
One for the upper level and one for the lower level.
Each generator would have a breaker at the generator.
So here is the question.
Because the neutral and ground are bonded together at the meter center, I was looking as doing a separately derived generator for the upper level.
This would feed through a 250A disconnect on the lower level, splitting it into two feeds, run up to two 4 pole ATS on the upper level.
I would be grounding the generator at it’s pad and provide a grounding electrode conductor from the generator to the ATS’s.
For the lower service, the generator would be a non-separately derived with a service rated 3 pole ATS.
I would also have a grounding electrode conductor from the generator to the ATS.
This ATS would be grounded to the water line, building steel, and ground rod.
Do you see any issues with this?
Any suggestions?
thanks,
Jim
I have a new two story building under construction.
The owner decided, during construction, they would like to add a generator to pick up all building loads.
The building was set up with three services, 208v 3 phase, 4 wire.
There are two services feeding the upper floor and one feeding the lower floor (a bank).
The bank has a 600A CT metered service with an MDP located just inside the building.
The upper floor has two tenants and thus two services.
One service is 200A and one is 400A, both fed from a meter center on the outside wall.
I would like to split this building up and supply it with two generators, for cost reasons.
One for the upper level and one for the lower level.
Each generator would have a breaker at the generator.
So here is the question.
Because the neutral and ground are bonded together at the meter center, I was looking as doing a separately derived generator for the upper level.
This would feed through a 250A disconnect on the lower level, splitting it into two feeds, run up to two 4 pole ATS on the upper level.
I would be grounding the generator at it’s pad and provide a grounding electrode conductor from the generator to the ATS’s.
For the lower service, the generator would be a non-separately derived with a service rated 3 pole ATS.
I would also have a grounding electrode conductor from the generator to the ATS.
This ATS would be grounded to the water line, building steel, and ground rod.
Do you see any issues with this?
Any suggestions?
thanks,
Jim
