I'm no whiz on lightbulbs, so correct me if I'm mistaken about that lamp being a plain old 120 volt incandescent lamp. If that is so, I've never seen one made for 277 volts, but I have heard of them being used on mine equipment. Are you sure the correct type of lamp is installed?
Are you sure the fixture doesn't have a step down transformer? If so & it is a listed fixture, it is in compliance with 210-6(c)(2).
Anyway, digging out my '87 codebook, this would have been a violation in the '87 code as there was not even a mention about a transformer & listed fixture, had to be a mogul base & electric discharge type lamp type or other type of base (such as fluorescent type socket).
[This message has been edited by Tom (edited 11-11-2002).]
Few things are harder to put up with than the annoyance of a good example.