Path: utzoo!attcan!uunet!husc6!purdue!decwrl!cookie.dec.com!devine
From: devine@cookie.dec.com (Bob Devine)
Newsgroups: comp.sys.dec
Subject: Re: Plenum-Rated Ethernet Transceivers
Message-ID: <8805181618.AA12795@decwrl.dec.com>
Date: 18 May 88 16:18:07 GMT
Organization: Digital Equipment Corporation
Lines: 21

> Nobody seemed to know anything
> about the meaning of their NEC 725 (?) specification vs. this crazy
> sticker with an apparent misspelling.
 
  There are *many* regulations regarding building codes.  I suspect
what happened here [cable allowed in "air carrying space" but not
in "plenums"] is due to a local or national fire code.  For a plenum
you want to have non-PVC cable so that the toxic fumes caused by a
fire burning the cable are not circulated by the plenum.

  The "NEC" stands for the National Electrical Code.  From what I 
remember, it is Article 800 that controls cabling.  Article 800
defines 4 types of cables (this is the entent of my notes, if
you want more info you'll have to get the actual regulations):

1. Communication cable = general stuff, probably what you bought
2. Communication riser cable = for use in shafts, is fire-resistent
3. Communication plenum cable = used in plenums, no toxic fumes
4. Communication cable, limited use = for use in noncombustible pipes

Bob Devine