422.18 Support of Ceiling-Suspended (Paddle) Fans.
Ceiling-suspended (paddle) fans shall be supported independently
of an outlet box or by listed outlet box or outlet
box systems identified for the use and installed in accordance
with 314.27(D).
410.36 Means of Support.
(C) Luminaire Studs. Luminaire studs that are not a part
of outlet boxes, hickeys, tripods, and crowfeet shall be
made of steel, malleable iron, or other material suitable for
the application.