Leviton’s plenum patch cords are assembled using plenum rated solid-conductor cable (the same cable used for horizontal runs). The rating does not apply to the plugs and boots because they are made from a polymer material, and the exposed surface of the plug/boot would be very small. Below is an excerpt from paragraph 18.2 of the UL standard concerning Plenum ratings. Sub-paragraph “e” is most relevant.
“Material in a compartment handling conditioned air for circulation through a duct system shall have a flame spread rating of not
more than 25, and a smoke developed rating of not more than 50, when tested as specified in Surface Burning Characteristics of Building Materials and
Assemblies, CAN/ULC-S102, and their requirements for Standard Method of Tests For Surface Burning Characteristics of Building Materials, UL723. This requirement does not apply to the following.
e) Molded or formed components (not liners) of polymeric materials in such quantities
that their total exposed surface area within the compartment does not exceed 0.93 m2 (10 ft2).”
Based on the size of Leviton’s plug/boot, you would have to include over 6000 connections in a plenum space before you approached the 10 ft2 of exposed surface area. The standard goes on to say that polymer products that exceed the surface area limitations can have a UL flame
rating of 94-5V to qualify for plenum spaces. The polycarbonate used in our plugs & boots has a UL94-V0 rating. Again, the flame
rating is not a factor because the parts are so small.