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.