NEC 250.118, 250.122(F), 392.60

D

Dale001289

Senior Member
Location
Georgia
We have a client who thinks the embedded ‘grounding loop’ that ties into the MCC bus is the EGC for parallel 500 kCMIL cables ran entirely in cable tray from a switchboard feeder CB to the MCC MCB. He doesn’t recognize the cable tray represents the EGC and needs to be tied at each end for low impedance fault path. Not sure how to convince them that the tray itself is the EGC per 392.60 and doesn’t appear in 250.118 and the buried ground loop is only an equipotential grid - not a fault path for the circuits…suggestions?
 
Maybe 300.3(B) -- all conductors, including equipment grounds, generally need to be run together. Embedded grounding loop isn't run with the other circuit conductors.
 
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