Installed a 250kw diesel generator, engineer called for 2/0 for grounding electrode. Electrical Inspector failed it because he said it must be a 3/0 because the line side of the main disconnect is 3 sets of 400‘s as per 250.66. I agree with the inspector but the engineer is pushing back saying that is not the way to figure ground size for generator, can someone please tell me where to find the the proper grounding size, thanks
Grounding Generator
- Thread starter Sparkylu3
- Start date
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The devil is going to be in the details. If the generator is a SDS (Neutral is switched in the T/S) then there must be a grounding electrode system and 3/0 would be the correct size based on the (3) 400s unless you are connecting to a ground rod or UFER ground where there are exceptions on GEC size.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
In grounding and bonding, use of the correct terms is vital.
Review the NEC definitions for grounding electrode conductor and grounding, snd ssk your question again.
Or, "what color is it and what does it do" Mike Holt.
Review the NEC definitions for grounding electrode conductor and grounding, snd ssk your question again.
Or, "what color is it and what does it do" Mike Holt.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I'm not surprised that you're getting push back from the engineer. This sounds like a boiler plate sizing which we see often. We had a drawing that listed the GEC sizes based on the kva size of each transformer regardless of the derived conductor size. How did the engineer come up with #2/0?
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