plenum vs. non-plenum FREE cabling and networking Helpdesk
 Question by David Patton posted 17 Jan 2003
 plenum vs. non-plenum
I am running Cat5E cable through the exposed bar joists in an industrial environment. As far as i understand, i am not required to use plenum rated cable in this case. However, does the plenum rating offer any added protection for the cable in this somewhat harsh environment? I haven't been able to find any info on the inherent differences in the materials between plenum and non-plenum cable.
 Answer by Dmitri Abaimov posted 28 Jan 2003
Dear David,

I would not recommend using plenum in this case (unless this is the only one you have available off-shelf). First of all, this is not a plenum environment, you're correct. Besides, plenum cable increases cost of a system for a factor of two-to-three. You can much better use this money to install more drops, for example, and make your sytstem more flexible. Besides, plenum cables are generally harder for installers to handle, which increases installation time (maybe not significant, but anyway). One other thing I should mention: since the outer jacket material is so expensive, cable manufacturers make the jacket thinner, which makes cable less protected from mechanical problems as well as electromagnetic interference from other cables (alien crosstalk).

Regular cables have outer jacket made of PVC composit. Plenum cables use fluoropolymers, primarily Teflon (r) by DuPont

Dmitri Abaimov, RCDD

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