Does anyone see an issue with running 480V 4000V Busduct under a raised floor? The floor does is conditioned and the busduct would be fully enclosed, just as if it were abouve the ceiling.
BTW: This access floor does not fall under article 645.

If the floor space is accessable for the lenght of the duct, I don't see why not, others may not agree.....

As long as the busway fits within the limitations of 300.22(C)(1), then it's fine.