I'm a bit confuzed. We have installed a 400amp panel with a main breaker that is fed from a 400amp disconnect that is fed from the bus bar in a distribution panel that is 2 switches downstream from the buildings service entrance The engineer states that our 400amp panel ground requirement is calculated from 250.122 table. The ahj states that we must use 250.66 table which covers grounding electrodes for services. Who is correct? Thanks.
AHJ vs. EE on grounding.
- Thread starter Hoodood
- Start date
- Status
That's what I thought. Thanks for confirming. Yes, it's an indoor mall. Landlord metered too.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
What kind of ground requirement are you asking about?
The equipment grounding conductor with the incoming primary to the transformer, the bond between X0 and frame, the grounding electrode conductor from the separately derived transformer or the grounding conductor that leaves the transformer secondary out to the load?
The equipment grounding conductor with the incoming primary to the transformer, the bond between X0 and frame, the grounding electrode conductor from the separately derived transformer or the grounding conductor that leaves the transformer secondary out to the load?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The part in bold is by definition a feeder and would require an EGC based on T250.122.
If you're using metallic conduit you don't even need wire type EGC.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Update, AHJ folds!
Update, AHJ folds!
Thanks to all! We called the AHJ and whipped out the code book. My boss said change the ground for the inspector. I said NO, I have the code references. It took a minute or two before the inspector said OK. But no sorry? Win some lose some. It's nice when you win! Thanks again guys.
Update, AHJ folds!
Thanks to all! We called the AHJ and whipped out the code book. My boss said change the ground for the inspector. I said NO, I have the code references. It took a minute or two before the inspector said OK. But no sorry? Win some lose some. It's nice when you win! Thanks again guys.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Inspectors make mistakes too. One advantage of "knowing the code" is to have an intelligent challenge when you think that someone is incorrect. Or just post the question here.
GerryB
Senior Member
- Location
- woodbridge, ct. USA
Maybe you'll get your "sorry" on the next job
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
I don't think the inspector owes you an apology. We all learn every day, and this time it was the inspector who learned something. The next time it might be you. When you fail an inspection legitimately, do you apologize to the inspector? I don't. We fix it and move on.
- Status