Is there an exception to the 6.5ft overhead clearance? Specifically I have a 24" x 24" junction box that only has 24VDC in it and would like to mount it onto a machine that will house an IO rack. (Note: this question is specifically associated with machine building and that will eventually be installed into a manufacturing facility.) The issues is that I have an overhead obstruction at 2" above where I need to put the box. NPFA 79 has the same requirements as as NFPA 70 and it seems as though there should be something in the code about enclosures with less than 150VAC in them.
Thanks for the help!