Ethernet FAQ-Plenum vs. Riser vs. Communications Cable

GET, LLC remain committed to providing more information about structured cabling for computer networks. This particular blog post examines the difference in use of three of the most popular cabling solutions and where the application is used in a building space.

In order to discuss Plenum (CMP) rated cable we must first discuss what plenum space is. Plenum space is the space in ceilings or between floors, which facilitates air circulation for heating and cooling systems. If air can travel between rooms in a building freely that air occupies a plenum space. The danger is when a fire breaks out. If the fire enters the plenum space, it encounters an oxygen rich environment that feeds it. By using plenum rated cable, one mitigates further fueling of the fire and reduces the toxicity of the smoke.

Riser Cable (CMR) is another designation found on cable and this is intended to be run between floors and not in a plenum space. Riser cable has a fire rating but not as strict as CMP so therefore CMP can be used in CMR applications, but CMR can never be used in CMP applications.

Communications Cable (CM) is general use cable suitable for in wall applications. It is rated to go in wall. It may not be used in applications where CMR or CMP is required, but CMR or CMP can be used for CM applications.


For more on structured cabling solutions for your respective business or building, please give GET, LLC a call at 671-797-0789 or see our website at www.get-guam.com for more details on how we can be of assistance.