250.66 vs 250.102(C)(1)

[ritelec]

When sizing an grounding electrode conductor, is anything over 1100cu - "3/0" max required ? Or do you have to do the 12.5% of area as required by 250.102(C)(1)

 

[texie]

When sizing an grounding electrode conductor, is anything over 1100cu - "3/0" max required ? Or do you have to do the 12.5% of area as required by 250.102(C)(1)

3/0 is max for a GEC. This is the reason that the new Table 250.102(1) was created to attempt to make clear that GEC max out but bonding does not.

 

[infinity]

That's it, if it's a GEC it's never required to be larger than #3/0. The 12.5% would apply to system bonding jumpers, main bonding jumpers, etc. Our 4000 amp services have the same size GEC as our 225 kva transformers.

 

[ritelec]

Thank you