Multigrounding neutral in separately derived system

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ciupol

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Hello All. I am new here and have a question. I tried to look for an answer but was unsuccessful. I have a 480:240/120V 1-phase transformer. On the secondary side I will install a panel and put system bonding jumper in the panel. Of course the connection to the grounding electrode conductor will be in the panel as well. Transformer and panel are in separate enclosures. Would it be allowable to bond grounded conductor (neutral) to GEC at transformer enclosure without bonding the enclosure itself to GEC? Enclosure would be grounded through supply-side bonding jumper from the panel. If this is not permitted can somebody, please point me to the appropriate article in the code.
Thanks.
 
The GEC and SBJ are located together in either the transformer or panel, not both. To bond the GEC to the neutral without hitting the enclosure would violate article 250.30(A)1 (A). Welcome to the forum!
 
May help:
transformer.jpg

I believe 250.30(A)(1) may contain the wording you are looking for "any single point"
 
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RUWired said:
The GEC and SBJ are located together in either the transformer or panel, not both. To bond the GEC to the neutral without hitting the enclosure would violate article 250.30(A)1 (A). Welcome to the forum!
Click to expand...
RUWired, thanks for your answer. After reading article 250.30 few more times I think that such installation would violate 250.30(A)(5) rather than 250.30(A)(1)(a). The latter one talks only about SBJ and its location. Please correct me if I'm wrong.

augie47 said:
May help:
Click to expand...
augie47 said:
View attachment 10117

I believe 250.30(A)(1) may contain the wording you are looking for "any single point"
Click to expand...


Augie I understand that SBJ can be installed at only one point in separately derived system and it was not my intention in the original post to install it in two points.
 
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You can use 250.30(A)5 as well. A-5 says the connection of the electrode to the grounded conductor shall be made at the same point where the SBJ is made, and A-1 says the SBJ shall connect the grounded neutral conductor to the enclosure. I don't see any objection to installing an additional GEC at the transformer as long as its connection is to the frame or equipment ground conductor and not to the xo.
 
RUWired said:
You can use 250.30(A)5 as well. A-5 says the connection of the electrode to the grounded conductor shall be made at the same point where the SBJ is made, and A-1 says the SBJ shall connect the grounded neutral conductor to the enclosure. I don't see any objection to installing an additional GEC at the transformer as long as its connection is to the frame or equipment ground conductor and not to the xo.
Click to expand...

I agree. It then is just an auxiliary grounding electrode as permitted by 250.54.
 
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