It’s all too easy to underestimate the complexities of office or data center low-voltage cabling requirements. Unfortunately, many people are unfamiliar with the National Fire Protection Association (NFPA) and assume that any cable will suffice for their needs, rather than checking to see if their cables meet NEC (or NFPA 70) requirements.
When planning and budgeting for a new cable installation or hiring a low voltage cabling contractor, businesses should be aware of the various cable ratings referenced in the NEC. CL/CM cables, CMP cables, and CMR cables are examples of these ratings, known as a general-purpose/residential, communications plenum, and communications riser. In addition, there are a few other communications cable ratings that apply to outdoor environments, but that will be the subject of a future blog.
It’s worth noting that the CL/CM, CMP, and CMR designations only refer to the cable’s “jacket” rating and fire resistance properties; they have no bearing on the cable’s data transmission capabilities. Most commercial spaces will need to use plenum or cat6a riser-rated cables To meet fire safety codes. As a result, many people wonder what the difference is between plenum and riser cables.
What exactly is a Plenum?
To understand plenum cabling, you must first understand what a plenum is. “A plenum is a separate space used for air circulation for heating, ventilation, and air conditioning,” according to a Medium article. These areas can return air to the heating, ventilation, and air conditioning (HVAC) system of the building.
Any materials installed in a plenum space, including cables, must be rated for that environment, primarily because smoke from burning cables can easily be sucked into the HVAC system and spread throughout the building.
READ MORE: Villain Perfume Review
What is a Riser?
A riser is a vertical shaft or series of rooms within a structure that allows primary utilities like electrical conduits, water supply lines, and communications cabling to be distributed vertically. For example, the riser for communications cabling could be a separate room on each floor or a shared room with electrical equipment. The room is self-contained in either case and is not used to recirculate air to the HVAC system. As a result, the requirements for fire resistance for materials installed in these rooms are less stringent than those for plenum spaces. Plenum Cabling is a term that refers to a type of cabling that is used.
Plenum cabling, also known as CMP according to the NFPA’s NEC guidelines, is the cabling that has a jacket made of polyvinyl chloride (PVC) or fluorinated ethylene polymer (FEP). When compared to other plastic polymers, these materials are more fire-resistant and emit fewer toxic fumes.
Plenum cables are required when running cables through plenum spaces. Plenum cabling is more expensive than riser cabling because plenum cables are built to a higher fire resistance standard. While plenum cabling can be substituted for riser cabling in a “riser” space, riser-rated cables cannot replace plenum-rated cables in a plenum space.
READ MORE: Saree Silhouette Review
What is Riser Cabling, and how does it work?
The National Electrical Code (NEC) defines riser cables as the cabling that meets the fire resistance standards for installation within a vertical riser or a non-plenum environment.
An HVAC system with a ducted-return configuration, for example, is one example of this because separate ducts are used to recirculate air to the system rather than using the entire space above the drop ceiling. In the event of a fire, this helps prevent the spread of smoke and toxic fumes throughout the HVAC system from burning cables (or drop ceiling tiles).
To summarize the differences between the plenum and riser-rated cables, the cost is a significant consideration. Still, it comes down to how fire-resistant their jackets are and how much smoke they emit if they burn. Plenum cables have a higher fire resistance than riser cables, making them a lower risk in a building fire (which are, in turn, safer than general-purpose cables).
READ MORE: Dinoshake Review
When deciding between Plenum and Riser Cabling, there are a few terms to keep in mind. When looking for plenum or riser rated cables, here’s a quick rundown of acronyms and other terms to be aware of:
Cables with the letters CL, CM, and CMG. Residential-grade or general-purpose cabling is referred to as this. In riser or plenum environments, it is not suitable for commercial use.
CMR Cables are a type of cable. Riser for communication. Approved for use in stairwells. CMP Cables are a type of cable used to connect Plenum on Communications Approved for use in plenums and risers.
The National Fire Protection Association (NFPA) is a non-profit organization dedicated to preventing fires. The National Electrical Code was created by this organization.
The National Electrical Code (NEC) is a set of rules that govern electrical installations (NFPA 70). This guide is intended to establish a standard for electrical safety in residential, commercial, and in g elesdustrial structures.
READ MORE: Park Avenue Voyage Review