after reading the code again I agree and i also agree with george's reason but what about the exception to 250-97 where a box with concentric ko's is listed for the purpose of grounding. another words there are boxes or enclosures with concentric ko's that are tested and listed for equipment grounding without a bonding jumper? Is it correct that bonding around reducing washers (donuts) is always required b/c they are not tested or listed to conduct fault current at any voltage?
