I have a Contractor who maintains that an acceptable way of bonding/grounding a metal box used in a NM cable installation, would be to wrap the bare equipment ground wire around the screw that is used with the cable clamp. Now there are no cables under the clamp and the clamp is still installed so the bare wire is under the head of the screw and between the screw head and the clamp. I maintain that the Contractor should be using the 8-32 hole provided for installing a GREEN screw and not use the cable clamp screw what-so-ever for grounding. I don't think he should even use the silver colored cable clamp screw in the hole provided for the GREEN ground screw. I need something official for a reference. Thank You in advanc.
There is no code rule that requires the use of a "green" screw for the connection of the EGC. The use of the clamp screw with the clamp still installed would be a violation of 250.148(A), but there is no violation if the clamp is removed and the clamp screw is used to connect the EGC. Don
...Now there are no cables under the clamp and the clamp is still installed so the bare wire is under the head of the screw and between the screw head and the clamp.
Why the heck would you leave an unused clamp in the box anyway? Not only would it prevent the screw from being firmly tightened on the ground wire and is a violation of 250.148(A) but it counts as a conductor in calculating box fill.
Dunno, but whenever I see unused clamps still in place it screems DIY!