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NEC Cable Fire Rat ings Guide

Scope:

Cable f i re r at i ngs are somet hing oft en overlooked when your cable purchase ismade, only to be scrut inized by bui lding inspector s aft er the inst al lat ion. TheNati onal Elect r ic Code art ic les 700-800 specify f lamm abi l i t y rat ings for cert aininst al lat ion si t uat i ons, but muddle t he issue by al lowing subst i t ut ions t o bemade among their rat ing syst ems. The purpose of t his document is t o providesome degree of clari t y in deciding which rat ing is appropriat e for yourinstal lat ion environment.

Plenum:A Plenum is defi ned as any enclosed area t hat faci l i t ates environment alair handl ing. An example would be an air condit ioning duct or an air routingdrop cei l ing. However, a plenum can be any air space bet ween wal ls, underf l oors, or above non air handl ing dropped cei l i ngs i f duct work is not sealedcorrect ly. Plenum cables are held to the most str i ngent t est ing of any of t hecables rat ed by t he NEC, r ated f or bot h f lamm abi l i t y and smoke generat ion.

Plenum Rating Codes

Signaling CL2POpt ical Fiber OFNP

Communications CMPCOAX/ Ant enna CATVP

Riser:Riser cables do just what their name suggests, they rise between floors.

Riser cables may also penet rat e ei t her f i re r ated wal l s or f loors. The cables aresubj ected t o f l ame t est s only, and are not held t o as high of a st andard asPlenum rat ed cables. Plenum cables may be subst it ut ed f or Riser.

Riser Rating CodesSignaling CL2ROpt ical Fiber OFNRCommunications CMRCOAX/ Ant enna CATVR

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General Purpose:General Purpose cables may be used anywhere in commercial buildings

ot her t han areas whe re Riser or Plenum cabl es are requi red. The cables aref l ame t est ed and held t o a lower st andard t han ei ther Riser or Plenum cables.Both Plenum and Riser rated cables are acceptable substitutes for GeneralPurpose rat ed cabl es.

Gener al Purpose Rating CodesSignaling CL2Opt ical Fiber OFNCommunications CMCOAX/ Ant enna CATV

Residential:Resident ial rat ed cables are rat ed f or use in homes, t hough t hey may be

used in commercial bui l dings i f conduits included wi t h t he inst al lat ion.Resident ial Cables are held t o a lower st andard t han any of t he ot her 3 t ypes.Plenum, Riser, and General Purpose rated cables may be substituted forResidential rated cables.

Resident ial Rating CodesSignaling CL2X

Opt ical Fiber N/ ACommunications CMXCOAX/ Ant enna CATVX

Low Smoke Zero Halogen:Low Smoke Zero Halogen (LSZH) Cables have been developed to

el imi nate t oxic gasses produced w hen wat er int eracts wit h subst ances releasedwhen a cable s j acket burns. They are recomm ended for use in enclosed areaswit h l i t t le venti l at i on or in areas where sensit ive equipment could be damaged.While r equir ed i n m any sit uat ions by European st andards (RoHS), LSZH is not anNEC; r ather i t s an indicat or of t he j acket and insulat or chemical makeup.Cables may be rat ed Riser or General Purpose in addit ion t o designat ed asLSZH.