Plenum is *also* usually better shielded than standard PVC, thus good for running in walls, where you most likely would be running it along power lines, etc. Yes, Plenum IS required for HVAC systems, etc...I was one of two in a massive upgrade at my old high school, and we had to beg for 3 spools of the stuff. (This was two years ago - cable ran about $350 a spool then) _______________________________________________ TCLUG Mailing List - Minneapolis/St. Paul, Minnesota Help beta test TCLUG's potential new home: http://plone.mn-linux.org Got pictures for TCLUG? Beta test http://plone.mn-linux.org/gallery tclug-list at mn-linux.org https://mailman.real-time.com/mailman/listinfo/tclug-list