Is there a need for Multiple ground points!?!?!?!

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coke03p

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Hey everyone, once again I have another problem.
Ok I have a generator powering a 350 Amp 3 phase MDP. Out of that it is feeding 6, 60 Amp 3 phase breakers which are feeding 6 Sub panels which have 10, 20 amp single phase breakers each. Is it necessary to carry the ground continuously from the source (generator) through the MDP and to the Subpanels, or can I ground at each panel. Thanks for everybodys help again. We seem to have a great debate over this one here at the shop and I need an answer. Thank you.
 
Re: Is there a need for Multiple ground points!?!?!?!

Couple of questions -

Is this a standby or prime application ?

Is there a transfer switch and a utility source involved at all ?
 
Re: Is there a need for Multiple ground points!?!?!?!

couple of answers...

PRIME POWER

NO transfer switch

NO utility
 
Re: Is there a need for Multiple ground points!?!?!?!

Then, it's my opinion (and certainly subject to arguement) that the installation has to be treated as any other. You are basically "the utility". All of Article 250 would apply and there should be no N-G bonds other than at service entrance.

The generator as installed as a prime source can not be treated as a seperately derived system.

If there are transformers downstream, then they would be SDS's.
 
Re: Is there a need for Multiple ground points!?!?!?!

Well thank you for the info and the code ref. that helps alot. I will definatly show this up to my higher and let them know. I once again appreciate all the help!
 
Re: Is there a need for Multiple ground points!?!?!?!

If you reground the neutral, you will have neutral current on all metal parts it is bonded to, including raceways. It can cause fires, shocks and improper operation of electronic equipment. Don't do it.
I'm pretty sure 250.32(A)(2) will go away with the 2008 NEC. Its currently not allowed in Washsington and New Mexico.
 
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