CMR CAT6 in environmental air space

[tommym]

Can CMR rated CAT6 cable be installed in gutters, flex, or conduit under an 18" raised floor that is used to supply environmental air? The area is office space, does not fall under 645. The communications contractor is installing this cable in a 17 story high rise. The installation is modular utilizing 4"x12" enclosed cable tray, 6"x6" screw cover gutter and flex. Article 800.53A and Table 800.53 list CMP cable. The communications engineer on the project stated that "plenum rated is only necessary if the cable is run exposed" and the present installation meets the code. The installed Type CMR cable is not exposed. Need your help guys.

 

[leecordochorea]

Requirement for plenum rated cable applies only to exposed cables running through plenum spaces. Since your cables are in raceway and not exposed, they need not be plenum rated.

 

[tommym]

Does 800.53(A) apply? (2002 NEC). "Listed plenum communications raceways shall be permitted to be installed in ducts and plenums as described in 300.22(B) and in other spaces used for environmental air as described in 300.22(C). Only Type CMP cable shall be permitted to be installed in these raceways."

 

[don_resqcapt19]

Tommym,
800.53(A) only applies when using "listed plenum communications raceways". (note the code section is 800.154(A) in the 2005 code) If you are using metal raceways, this section does not require the use of plenum rated cables. Also note that you may need to be looking at Article 725 and not 800 as many code experts say that computer wiring is covered by 725 and not 800. 725.3(C) sends you to 300.22 for this application.
Don