I ask because my local Home Depot employees who claim to be electricians told me that any communications cable installed in a commercial building must be plenum rated. (They don't even know what a plenum is). I am aware of the definition of a plenum. And from everything I can find in the code, I only have to use plenum rated cable when installing in a plenum. But, I'm trying to get other input, because, once again, the Home Depot guys sware that that's the rule - ANY commercial wiring.
