Mike holts daily question today!!

[Jpflex]

Today’s question: a service having 3 sets of 600 kcmil Is to have 3/0 size grounding electrode but my NEC BOOK specifically shows 1/0 required in table 250.66 for conductors 350 - 600?

 

[Barney B]

3*600=1800

 

[roger]

Always read the whole section the table(s) is/are in and the notes accompanying the table(s)

 

[Jpflex]

Always read the whole section the table(s) is/are in and the notes accompanying the table(s)

I assume is has to do with 3 sets or paralleling? I’ll have to look into this

 

[Jpflex]

3*600=1800

Yes I see the note on the bottom now. However I don’t have a visual idea of how this connection hook up works? As far as I know utility hooks to service entrance at service point but this makes it seem as if there is a parallel splice at this point for multiple sets of service/ feeders?

If there were just a diagram to show how this setup looks?

 

[infinity]

I assume is has to do with 3 sets or paralleling? I’ll have to look into this

Yes the wording "3 sets" would imply that they are parallel conductors. So as Barney stated you're SEC's size is 1800 kcmil which is what you would use in T250.66 to come up with a #3/0 GEC.

 

[Barney B]

Perhaps this diagram will help a little. Sorry for the quality of the artwork.