Hi Kyle, The flame ratings are actually all harmonized now. (FT, UL and NEC). Information about the comparisons between the ratings can be found in applicable UL and CSA standards, or in the NEC or the Canadian Electrical Code. I also have seen some emails with some information that is slightly inaccurate, but common assumptions: The NEC "P" ratings (i.e., CMP, CL2P, etc.) are NOT tested for low toxicity smoke. They are just tested for optical density of smoke emissions (visibility). A lot of CMP and CL2P cables out there are EXTREMELY toxic went burning. They just emit less visible smoke. The plastics used to reduce emissions and increase flame retardance produce highly toxic gasses. There is a hierarchy of flame ratings that are spelled out in the UL/CSA standards, as well as the NEC and Canadian Electrical Code: For example, From low to high per Article 725 of NEC: VW-1(CL2X?? I forget!!) wiring from wall to unit, or in electrical conduit CL2 (UL1581) Anywhere VW-1 is allowed, plus in Cable Trays (excpet in Risers or Plenums) CL2R (UL 1666 ?? I forget) Anywhere CL2 and VW-1 are allowed, plus in Risers CL2P (UL910) Anywhere CL2R, CL2, and VW-1are allowed, plus plenums. In the NEC, CMX, CM, CMR and CMP can be substituted appropriately in Article 725 above, as well as the appropriate level of Canadian FT-x ratings... I hope this helps. If you have any further questions, I will try to help.. BR, Robert Tims Engineering Project Leader Software Product Integration Ericsson Internet Applications, Inc. 145 Crossways Park Dr. W. Woodbury, NY 11797, USA Tel: 516-677-1138 Fax: 516-677-1111 Pager: 516-891-8358 Email:[email protected]
-----Original Message----- From: Ehler, Kyle [mailto:[email protected]] Sent: Thursday, October 04, 2001 11:09 AM To: [email protected] Subject: Wiring flame ratings If I may ask a back to basics question. The country specific agency flame ratings for insulated wiring seem to not be harmonized. Some materials such as limited current (signal) interconnect wiring are marked as VW-1 while others are marked with FT-1,2,3,4 or CL-2. VW nomenclature is a UL rating for wiring, while FT-x is a Canadian rating and test method, and CL2 is a NEC rating. Have I left any out? (;^) Is there such a thing as a cross reference table that indicates which is equivalent (and per application?) ? For example, FT4 = VW-1 = CL2 for vert./horiz. raceway? Inquiring minds... Kyle Ehler KCOIQE < mailto:[email protected] <mailto:[email protected]> > Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321
