Neutral to ground at more than one point.

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makalroy

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Hello, I had a engineer tell me the NEC. allows bonding neutral to ground, at a generator, then the MDP, and then the sub panel. Just not at the load panel inside the building. Is he crazy or am I missing something.

Here?s the set up; Gen to a mdp. that feeds 4 to 8 sub panels that are all out side. Then the sub panel feeds 10 to 20, metal containers that have their own panel inside.
The containers are used for living space, offices, bathrooms or storage.

Thanks for any help, please use code ref.
 
What about 250.30A1 "This connection shall be made at a single point on the separatly derived system from the source to the first disconnecting means or OCPD" 2005 NEC


and 250.30 A 1 Ex.2 would not allow a main bonding jumper at the sub panels.
 
makalroy said:
Hello, I had a engineer tell me the NEC. allows bonding neutral to ground, at a generator, then the MDP, and then the sub panel. Just not at the load panel inside the building. Is he crazy or am I missing something.
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You can bond the equipment to the neutral once in/at each structure as long as there is not a parallel EGC between structures.
 
makalroy said:
What about 250.30A1 "This connection shall be made at a single point on the separatly derived system from the source to the first disconnecting means or OCPD" 2005 NEC
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That's correct. Will there be an EGC between the genny and the building?


and 250.30 A 1 Ex.2 would not allow a main bonding jumper at the sub panels.
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That's always the case when there is (or should be) a separate EGC.
 
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