Ok, I'll give more to the story. The guy I worked for the majority of my career taught me that regular old drywall screws were illegal to use because they are not corrosion resistant. I asked my new boss for some hex heads and he wanted to know why I didn't have drywall screws on the truck. I did have drywall screws on the truck, but since I was under the impression I couldn't use em, I didn't think to.
After some discussion and a call to my old boss to find out just where to find this information I have two codes that he cited for his reasoning.
300.6 Protection Against Corrosion and Deterrioration
Raceways, cable trays, cablebus, auxiliary gutters, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the enviornment in which they are to be installed.
358.12 (6) Where praciticable, dissimilar metals in contact anywhere in the system shall be avoided to eliminate the possibility of galanic action.
Location, Damp. Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.
By putting the word "some" in the definition of damp locations, it opens it up to interpretion if the specific basement is moist enough to be considered damp. I would argue that you should not use drywall screws because it would be hard to argue the inspector IF he didn't like the use of drywall screws. Then take into account that drywall screws and normal, everyday emt one-hole straps are dissimilar metals, if an inspector wanted to, he could fail it and not in just basements.
That is our arguement, now I am prepared for all the ridicule for making such a big deal out of something pretty minor.
