Thanks Larry. I'm not sure what you mean about the plenum cable being ripped out if inspected. This job will definitely be inspected. Could you elaborate?

Peter, as for the definition of a plenum space, or when to use plenum-rated cabling, here are my criteria- There is a 15 ft. high concrete ceiling with a suspended tile ceiling below it at 8.5 ft high. Above the suspended ceiling is open air. No conduit. Daly City, CA 94014 codes apply.