Distance to Ground Grid

[charlie b]

An existing ground grid consists of 9 ground rods in a 3x3 array, with 10 foot spacing. The tenant insists that they need this grounding electrode system, in order for their equipment to work properly. However, a new building addition under design will have the existing grid under its footprint. So I am planning to put a new ground grid, same design, on the other side of the addition. That will put it around 150 feet away from its point of connection to the existing building. The new addition will have a separate service and interior electrical distribution system. The addition will house the same types of equipment as the existing building.

Three questions:

1. Does it matter how far a ground grid is located from the building it serves?
2. Can I connect both the existing building and the addition to the same (new) ground grid?
3. The shortest path that a grounding electrode conductor could take from the existing building to the new ground grid would have it running under the addition. It would therefore be inaccessible for most of its length. Is that a problem?

 

[PaulMmn]

Will the existing grid be left in place and functional? And, assuming the floor of the addition is concrete, will that be a "ufer?" (sp)

 

[tom baker]

Moderator DereckBC is an expert on radio systems and towers, he would be the one to answer this question.

 

[charlie b]

Paul: My current plan is to demolish the existing grid once the new one is in service. I don't know whether the existing grid would cause issues with the structural design, but I will check.
Tom: The equipment is not a radio tower, but rather a flight simulator.

 

[don_resqcapt19]

i would leave the existing one and not worry about the distance on the new one, as the grounding systems are not really doing anything functional, they just believe they are.