Greg,
Here in some of my towns the building or fire inspector will fail a job if wire, RX or other, is run through any ductwork in a resi bldg. There is one job here I was looking at and th tin knockers "Panned" a whole main girder. and when they did that, they enclosed not only wires, but there was a large waste line. "Panning" is when the tin knockers put a flat piece of tin across the bottom of your 2 X 10's and they use that area to move air instead of using a piece of ductwork itself.
