AC Electric
Member
I have a question I was hoping you can answer. 250.64E states " Ferrous metal enclosures for grounding electrode conductors shall be electrically continuous from the point of attachment to cabinets...and shall be securely fastened to the...fitting." Heres my scenario: 6awg CU stranded bare grounding electrode conductor traveling from the main disconnect to the ground rod running within a 1/2" EMT w/compression connectors attached to MD can (direct connection, no coccentrics). The conduit is ran along the face of the building (to protect wire from physical damage) in one complete bonded system (1-LB rigid; 2-connectors on each end of LB; 1-connector on the can; open bottom to allow the electrode conductor to exit to the rods.) Does the mentioned application have any need to install grounding bushings on each end and why?
I recently purchased the NEC handbook for this specific question and noticed that I am required to bond each end. On that article, it is contradicting itself and on the article of using EMT as a grounding conductor when not using a bonding conductor. Looking at the procedure for a mathematical standpoint, if the electrode (A) equals the service disconnect panel (B)-due to the bonding screw; and the service disconnect panel (B) equals the electrode grpounding conductor raceway (C)...then shouldn't A=C? There shouldn't be any potential difference if the conduit is bonded effectively. The concept of using grounding bushings on this application means all conduits coccentric or not, must have a bonding bushing on each end AND cannot be used as a grounding condutor.
I recently purchased the NEC handbook for this specific question and noticed that I am required to bond each end. On that article, it is contradicting itself and on the article of using EMT as a grounding conductor when not using a bonding conductor. Looking at the procedure for a mathematical standpoint, if the electrode (A) equals the service disconnect panel (B)-due to the bonding screw; and the service disconnect panel (B) equals the electrode grpounding conductor raceway (C)...then shouldn't A=C? There shouldn't be any potential difference if the conduit is bonded effectively. The concept of using grounding bushings on this application means all conduits coccentric or not, must have a bonding bushing on each end AND cannot be used as a grounding condutor.