New 2011 requirements for sizing of GEC on separately derived sys

[Cjmcelectric]

Hello all ,
I was wondering if some can explain 2011 code change for sizing a GEC in separately derived service . I'm mainly talking about the secondary side of transformer grounding to first means of disconnect ?
Thanks

 

[Smart $]

Hello all ,
I was wondering if some can explain 2011 code change for sizing a GEC in separately derived service . I'm mainly talking about the secondary side of transformer grounding to first means of disconnect ?
Thanks

I'm a little confused. Are you referring to a separately derived system or a service. Then are we talking GEC, MBJ, SBJ, EBJ, SSBJ (or some other acronym ).

FWIW, the requirements are more wordy... but AFAIK the sizing hasn't changed.

 

[infinity]

As Smart said you need to clarify what it is you're asking about, although the requirements for GEC's for a service or separately derived system would be the same size. Since you said GEC you would be referring to Table 250.66 which hasn't changed in decades.

 

[Cjmcelectric]

I will clarify and be back

 

[Cjmcelectric]

I am here to re ask my question and clarify it I was mistaken in first post . I mainly was wondering if anyone could clarify article 250.30(5) exceptions 1,2 or maybe give an example

 

[augie47]

I'll give it a shot:
Exception No 1 allows you to connect the grounding electrode conductor to the the equipment ground bar rather than to the grounded conductor IF the equipment bonding jumper is a wire or busbar.

Exception #2 comes into play when your SDS is part of listed service equipment. In those cases the service grounding electrode conductor for the service can be used as your SDS grounding electrode if it is of sufficient size, As best I can tell, this occurs where you have service gear that includes an SDS.