I assume you mean NM-b, most folks have never seen NMC.
I have asked a similar question myself and the closest thing to an answer I found is they consider the wet location to start on the face of the outside wall but I never really had that confirmed. It is also common to see regular metal device boxes in masonry served by Romex.
It is OK to "fish" Romex through voids in masonry if this is "dry".
