We are currently looking at expanding the structure of an existing electrical room and I had a question regarding the ground grid/ground ring for the new expansion portion of the building.
It appears that the existing building has a ground ring which encompasses the building with ground rods and test wells installed at the buildings corners. When expanding the building we planned on tying into the existing buildings ground ring and running a 4/0 bare copper wire along the perimeter of the new building with ground rods at each of the corners. The bare copper wire will be run within the building slab and stub up above the slab at the proposed equipment locations for switchgear, mcc's, panels etc..
The 4/0 ground ring with ground rods a the corners is what I have typically seen done for such installations. Am I on the right track with this type of ground installation for a new building expansion? Is there NEC reference provides these requirements or is this just a typical industry practice? I know 250.66 has requirements for grounding conductor so I'm wondering if this installation is discussed here?
Also when installing ground rods I have seen them installed as a single rod as well as in a triad configuration. Are there requirements with dictate the use of either configuration?
Thanks
It appears that the existing building has a ground ring which encompasses the building with ground rods and test wells installed at the buildings corners. When expanding the building we planned on tying into the existing buildings ground ring and running a 4/0 bare copper wire along the perimeter of the new building with ground rods at each of the corners. The bare copper wire will be run within the building slab and stub up above the slab at the proposed equipment locations for switchgear, mcc's, panels etc..
The 4/0 ground ring with ground rods a the corners is what I have typically seen done for such installations. Am I on the right track with this type of ground installation for a new building expansion? Is there NEC reference provides these requirements or is this just a typical industry practice? I know 250.66 has requirements for grounding conductor so I'm wondering if this installation is discussed here?
Also when installing ground rods I have seen them installed as a single rod as well as in a triad configuration. Are there requirements with dictate the use of either configuration?
Thanks