What is the difference between plenum or nonplenum?
Plenum or nonplenum wire refers to the outside insulation used on the wire. Nonplenum wire uses a standard PVC plastic for the insulation; plenum wire has special plastic insulation around it which, in case of a fire, has special nontoxic fume characteristics. Plenum wire typically is double the cost of nonplenum wire. Safety considerations, as well as building and fire codes, will determine the use of plenum or nonplenum wire.
