Existing Grounding electrode system

[alixenos]

Hi,

an electrical room that has an existing 1200A main switchboard is updated to have another 1200 A main switchboard being served from a new service.

for the 2nd service, Do we need to provide a new grounding electrode system? what about the existing one? where in the code I can find answers to those questions?

Thank you.

 

[infinity]

The new service has to be connected to a GES. If there is an existing GES you can use it. There is no requirement to install a new GES when adding a service to a building that already has one.

 

[Elect117]

I would add that you will most likely need to connect to the existing system on the new service.

250.50 - "All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system."

250.58 - "... If separate services, feeders, or branch circuits supply a building and are required to be connected to a grounding electrode(s), the same grounding electrode(s) shall be used."

 

[infinity]

I would add that you will most likely need to connect to the existing system on the new service.

250.50 - "All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system."

250.58 - "... If separate services, feeders, or branch circuits supply a building and are required to be connected to a grounding electrode(s), the same grounding electrode(s) shall be used."

And if someone decided to install a new electrodes or a new GES they would have to be connected to the existing GES.