Multi-family dwelling grounding

[dmott]

I am reviewing a set of plans for a multifamly building. All of the individual units are separated by firewalls. The building is divided into two "halves" with 8 or 9 units. Each "half" of the building is fed from its own service laterals from the same utility transformer. The laterals end at a service disconnect, which then feeds the meter stacks for that half of the building.

The designer shows the grounds for the two service disconnects connected to each other. (services are 600A, 120/240 VAC and the GEC is 2/0).

I cannot determine if this is permitted or not. Part of my confusion arises from the building code definition of a building vs. NEC and how that applies to services and grounding.

Any ideas??

 

[websparky]

Re: Multi-family dwelling grounding

250.58 Common Grounding Electrode.
..............the same electrode shall be used to ground conductor enclosures and equipment in or on that building. Where separate services supply a building and are required to be connected to a grounding electrode, the same grounding electrode shall be used.
Two or more grounding electrodes that are effectively bonded together shall be considered as a single grounding electrode system in this sense.