I've had several projects where a ground wire is required to be run.
That's a standard that is enforced at our local international airport (perhaps you've heard of it...O'Hare).
It's a requirement in Health Care occupancies.
I HATE relying on the conduit as the path. I've seen lousy couplings, busted connectors and gaps caused by expansion or evn just getting whacked by a passing forklift truck.
Unfortunately, I don't think there's much chance of a separate wire becoming a Code requirement soon...not with the price of Copper going nuts.
