There are a myriad of terms used in describing communications cables, i.e. CM, LSZH, PVC. But do you know what these terms really mean and how they can impact your business? Today’s post will explore the acronyms most commonly used and try and make sense of them all. Some of the more prevalent terms used to describe cable (at least in North America) are CM, CMR, and CMP. Whenever you see a “C” and an “M” used as part of a cable’s description, it indicates the cable can be used in accordance with the National Electrical Code (NEC). For the classification of CM, the standard outlines “general use,” or use in any situation where fire does not place restriction on the cable type installed.
CMR cable, or Riser-Rated Cable, is jacketed with a special material that helps prevent fire from spreading from floor to floor in vertical installations. It’s ideal when cables need to be run between floors through risers or vertical shafts.
A more stringent rating, CMP (or plenum-rated cable), is designed to limit flame propagation to under five feet, and to also limit the amount of smoke emitted in the event of a fire. Therefore, it is suitable for installation in air plenum spaces, including the space above a suspended ceiling.
In addition to these commonly used terms, there are a number of others thrown into the mix. Some of those include “PVC,” and “FEP.” These terms are more descriptive of the chemical compounds used in the manufacturing of the cable. PVC is most often associated with CMR-rated cable, and FEP refers more to CMP. It should be noted, though, these terms do NOT signify a product rating or any type of standards compliance – although it is often implied.
Around the rest of the world, other terms and acronyms exist to describe similar cables. A few examples are: LSZH, LSOH, and LSNH. ZH, 0H, OH, HF, NC, and NH indicate that the materials used in the cable production are free of Halogen, where LS indicates “Low Smoke.”
We hope this helps clarify some of the many acronyms you may stumble across. Our industry is famous for them, so we will definitely cover more in the future. If you have questions or would like more information, our knowledgeable sales staff would be more than happy to help!