The requirements for masts as supports differ from previous NEC versions. Have you kept up with Code rule changes? Do you know what changed here?
Previously, Sec. 225.17 consisted of a single paragraph. With the 2014 Edition of the NEC, the requirements are both spelled out better and broken out better.
The first requirement is at the “root” of 225.17. If you use a feeder and/or branch circuit mast, then only feeder and/or branch circuits may be attached to it. Someone else running communications cable, for example, might find that mast rather convenient but they are barred from using it.
The strength requirement is expanded from what it was in the 2011 NEC, and now stands out in its own subsection [225.17(A)]. The basic requirement (carried over from 2011) is the mast must be “of adequate strength” to withstand the strain imposed by the conductors, or it must be supported by guys or braces.
The requirements in subsection 225.17(B) are new. You can’t attach the conductors to a mast between the weatherhead (or end of the conduit) and a coupling, if the coupling is above the point of securement to the structure (or is above the structure).
