A new 800A service grounding for an old commercial facility

[Samardas]

A single line diagram for an 800A utility service shows Neutral and Ground Bus are connected inside the service panel. Also another bonding jumper connects the ground bus to the service panel enclosure. Finally the ground bus is connected to two-grounding electrode system. Cold water pipe is very far (about 75 feet away) and no building steel in the vicinity. Is this grounding setup acceptable (i.e connecting to the 2-grounding electrode system and not connecting to the cold water pipe or building steel) as long as the ground impedance is <=5 Ohms? Grounding always baffles me:?. Please advice. Thanks a LOT!!!

 

[ActionDave]

As long as you are using a wire jumper and not the panel as your connection between your grounding buss and neutral/grounded buss you can land the GEC on any of them but I think it would be a PIA. Just bring the GEC to the neutral and be done.

If the water pipe qualifies as a grounding electrode then you have to run a conductor sized 250.66 to it. 75' ain't that far at all. You already have two ground rods speced so your good to go on that if this is not new construction. If it is you most likely need a Concrete Encased Electrode.