Not as much as a metal raceway for a longer length around the conductor, but yes it should. If you can replace the bolt with a non ferrous bolt then it shouldn't.
Does it need to be non conductive or just non ferrous? Not saying your suggestions won't work, but a brass or stainless bolt would be non ferrous also.
Well, just cutting slots in a panel wall between single conductor entries is enough in that application.I don't know, you will have ferrous metal wrapping around 350 degrees of the conduit, I don't know if electrically connecting the ends would make a choke out of that or as you suggest would it have to be ferrous entirely to make a choke. :?
I don't know, and I doubt it's really a problem either way.
Calling 'Gar' to do some bench tests.
Same here, but if a PVC strap would work I went that route.
If you cut a slot from one hole to another and then screw on a ferrous nut that bridges the cut slot you might see extra heating in the locknut, probably only at very high current.
I think the discussion has left the OP's question. There should only be one hole for a GEC but, in isolated phase installations I agree and 300.20 would apply.
It is the effect that running a wire through a ferrous ring or sleeve creates a single turn iron core inductor (also called a choke). That inductance will restrict current flow and create a voltage drop when fault currents, but more likely lightening induced currents are applied to the GEC.
