I work in a large specialty machine shop and we are constantly moving equipment.  I want to use buss drop but the safety department requires conduit.  The safety department can't tell me where the regulation to use conduit comes from but I know the NEC allows buss drop.  I think that the conduit requirement got started because the city I am in had an addenum to the code requiring all commercial buildings be wired in conduit.  But the city dropped this requirement sometime in the 1990's.  I have spoken to the city inspector and he will allow me to use buss drop, but the safety department won't.  Can anyone point me to at regulation that requires conduit or some ammo to use to prove my point that buss drop is prefered.