Conditioned crawl space - plenum or not?

[dont_blow_up]

I'm confused about the definition of "plenum" and "air handling space". I have a residential application where the electrical wiring is routed throughout the crawl space. The crawl space is non-vented and conditioned with both supply and return ducting. Am I understanding it correctly that typical residential wiring methods (Romex) can be used as normal in the crawl space since there are supply and return ducts in the there? As in the crawl space is not considered a plenum or air handling space? On the other hand, if there was a free return air path to the crawl space (which there isn't in this case), then it would be considered a plenum or air handling space and Romex wouldn't be allowed?

 

[hbiss]

Am I understanding it correctly that typical residential wiring methods (Romex) can be used as normal in the crawl space since there are supply and return ducts in the there? As in the crawl space is not considered a plenum or air handling space?

Yes.

On the other hand, if there was a free return air path to the crawl space (which there isn't in this case), then it would be considered a plenum or air handling space and Romex wouldn't be allowed?

Yes.

-Hal