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plenum rated cat5e cable questions

J

JCROCCO

Senior member
Is there anything special about plenum rated cable? If so, I dont mind using it, tho it costs more.

My other question is "Is ther anything then special about the rj45 connectors of plenum rated cable?". We are using a storage space that is part of a plenum for the rack location of our switch, router, server, etc. If the cable is plenum rated, is there anything special to do about the termination points of the rj45 connectors? If I was to make and use home made cables from bulk using plenum rated cable, will there be any problems with the jacket, or connection, or loss of rating? Can the connectors themselves be in the plenum?

Thanks.
 
Plenum cables are used to meet fire codes of buildings. Ask your building administrator and they should be able to tell you whether or not you need it. Basically they don't produce toxic chemical when burned.

I use regular RJ-45 connectors for plenum cables and they work just fine. I'm not aware of any special grade of ends that you need to use, specifically for plenum cables.


 
Plenum cable DOES emit toxic fumes: it takes a higher flash point to ignite.

Plenum cable is not meant to be terminated with an RJ45: the cable is much stiffer than standard plastic sheath stuff and has very little strain relief.

Plenum cabling should be punched down to a panel (or at least an info outlet).

(for the record, Low Smoke Zero Halogen (LSZH) cabling emits the least toxins, but it still burns, and it's still toxic when it does)

FWIW

Scott
 
Is it not a good idea to have plenum rated cable ends (connectors) and equipment in a plenum space?

Is it not a good idea to make your own cable connectors for plenum rated cable?

The Cat5E runs will be from the wall jacks to a punch down patch panel in the plenum space. Is this acceptable?

If plenum cables are not meant to be terminated (home made), should I just then buy plenum rated patch cables for connecting the patch panel and the router to the switch?
 
Well, actually, you don't "make" cables for plenum rated spaces. The cables run from an info outlet near the user to a panel located in the closet after the cable surfaces from the plenum space.

There are no "Plenum Rated Connectors" because it's not meant to be terminated with an RJ45. Panels are not "plenum rated;" info outlets are not "plenum rated" because they are not devices you would (normally) find in a plenum airspace.

For the same reason, you would not find "plenum rated" patch cords. People do not exist in plenum spaces (though I realize some devices might .... like Access-points).

The usual solution, as far as I have ever heard, is that the cabling and info outlet should be put into conduit (and a box). A normal jumper (i.e., non-plenum) is used to connect the device. There is not enough toxic output from a single jumper (relative the the other toxic smoke generated in a commercial environment) to violate code.

The other solution would be enclose the whole shebang in a NEMA-rated cabinet (inside the plenum airspace).

If this is a commercial establishment, you might want to check out the National Electric Code relating to low-voltage electrical wiring.

Good Luck

Scott
 
Very good description thank you. I have found virtually nothing regarding this on the web. As Such, we have decided to not use a plenum return, and thus the point is moot for now, but the info was GREAT. Thanks again.
 
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