QUESTION FROM: John J. Deery ,

Joe my question is about 250.97. If you run a branch circuit to a safety switch and the conduit enters the enclosure through concentrics or eccentrics, are you required to use bonding bushings when the voltage excedes 250 volts to ground and you pull an equipment grounding conductor and bond it to the enclosure?

My concern: "Is the conduit being properly bonded?"

I spoke to Kevin Huss from Square D at 800-634-2003 TEC support, and was told to date Square D does not have an enclosure on the market with pre-stamped ko's listed by U.L. for the purpose of bonding.

We have new branch circuits being run at our plant 480 volts where the conduits are being landed in pre-stamped ko's of Square D enclosures with equipment grounding conductors, but are relying on the eccentrics and concentrics to bond the conduits.


Joe Tedesco, NEC Consultant