If it was my own facility? Absolutely, so that I would have maximum flexibility for future additions.
For a customer? Only if they are willing to pay for it or it was in the spec/bid. Assuming the conduits are big enough for another wire, the only additional cost is one more conductor, plus the time needed to make 2 more terminations. Buys a lot of "futureproofing" for a small incremental cost.
If the panel is called out as "208/120V", then I would argue that the presence of a neutral is implied, even if unused. If the panel is only specified as "208V", then no neutral.
[This message has been edited by NJwirenut (edited 11-10-2006).]
