Bonding and grounding of a 3000 amp 120/208 3phase service

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I have a new 3000 amp gear installed in a plant environment . We have installed new transformer and ground grid outside. So the bonding of the neutral is done at the transformer we have grounds installed in with are feeders coming to the main. I had planned on running 3/0 to building steel but do I need to hit the water main . This building has multiple services and the water main has already been bonded.
 

Gregg Harris

Senior Member
Location
Virginia
Occupation
Electrical,HVAC, Technical Trainer
I have a new 3000 amp gear installed in a plant environment . We have installed new transformer and ground grid outside. So the bonding of the neutral is done at the transformer we have grounds installed in with are feeders coming to the main. I had planned on running 3/0 to building steel but do I need to hit the water main . This building has multiple services and the water main has already been bonded.

250.58 Common Grounding Electrode. Where an ac system is connected to a grounding electrode in or at a building or structure, the same electrode shall be used to ground conductor enclosures and equipment in or on that building or structure. Where 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.

Two or more grounding electrodes that are bonded together shall be considered as a single grounding electrode system in this sense.
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
IMO. If your building steel is effectively grounded (250.52) and you bond to it and it in turn is bonded to the water line, you have met the Code requirement,
A properly size bonding jumper from building steel to water would serve for all the services.
 

iceworm

Curmudgeon still using printed IEEE Color Books
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North of the 65 parallel
Occupation
EE (Field - as little design as possible)
I have a new 3000 amp gear installed in a plant environment . We have installed new transformer and ground grid outside. ...
Curiousity Q:
I'm guessing the service is on the transformer primary. The 208 secondary is an SDS, not a service. Yes? No?

ice
 

Gregg Harris

Senior Member
Location
Virginia
Occupation
Electrical,HVAC, Technical Trainer
IMO. If your building steel is effectively grounded (250.52) and you bond to it and it in turn is bonded to the water line, you have met the Code requirement,
A properly size bonding jumper from building steel to water would serve for all the services.

I would agree it would be one complete grounding electrode system.
 
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