Alas, Greg, I argee - the code committee seemsintent upon expanding, rather than restricting the use of Romex; not the rather recent change allowing it's use in come commercial occupancies.
Maybe that's why we need to head this off at the pass; one is far more likely to encounter metal studs in commercial construction.
Steve, as for conduit being allowed for grounding, you are only partly correct.
Conduit is considered adequate for most branch circuits, and there the use of conduit as a grounding conductor ends. For feeders, and for bonding transformers, etc., a separate ground wire is needed.
If you want to get really pedantic, I was actually referring to using structural steel as the 'grounding electrode conductor,' (as opposed to 'equipment grounding conductor.')
"Common sense" is, right now, enough to make clear that you don't use light steel studs for this purpose, while an I-Beam will work. There is still some question as to the heavier 'sheet metal' structural forms used in those quick-to-erect light steel buildings. If you thought the code debateover 'sheet metal screws' was fun, just wait until we start debating 'structural steel!'
It's already pretty hard to isolate / not ground light steel framing in the course of doing other work - the example cited in this thread notwithstanding. Sort of like suspended ceiling grids; try NOT to bond one some time! Add a metal jacket to your wiring method - as with MC - and I don't think it's possible.
Sure, simply using a metal box will also create this bonding - I can hardly wait to see the arguments over where such would be required - but three remodels later, and it's anyone's guess where the 'isolated' sections are in relation to those boxes.
The more I think about this, I conclude that IF there is a problem, it lies in the choice of wiring method.
