Ethernet Cable Jacket Ratings: CM vs. CMR vs. CMP

Updated on Nov 1, 2021 by

Because ethernet bulk cables are installed in walls and ceilings, they must meet fire safety standards. The National Electric Code (NEC) has established fire ratings for ethernet cables, the most common of which are CM, CMR, and CMP. An explicit analysis of CM vs CMR vs CMP ethernet cable jacket ratings will be provided below, which may help you to learn and to choose the right fire rated cable.

CM vs. CMR vs. CMP Cable

CM vs. CMR vs. CMP Cable Jacket: What are They

CM Cable Jacket

CM stands for "Communications Multipurpose", it is a cable jacket fire resistance rating defined in Article 800 of the NEC. The CM cable jacket fire rating is the most basic ethernet jacket fire rating specified by the industry burn test standard UL 1581 and CSA FT1 standards.

Made from relatively inexpensive polyvinyl chloride (PVC), the CM cables are generally the minimum jacket ratings suitable for in-wall installation of ethernet cables and are appropriate for installation inside a residence or a single-story commercial building. As with any in-wall-rated cable, the goal is to prevent fire from traveling along a cable from one part of a building to another. The Ethernet cables labeled "Type CM" must pass a standardized flammability test before the cables are put into use.

CMR Cable Jacket

CMR stands for "Communications Multipurpose Cable, Riser", it is a cable jacket fire resistance rating defined in Article 800 of the NEC. The CMR cable jacket fire rating is a flame-resistant jacket standard specified by UL 1666 and CSA FT4 standards.

And what is CMR cable? Made from relatively inexpensive polyvinyl chloride (PVC) and insulated with high-density PE, the CMR cables are also referred to as "riser rated cables" and are typically developed for vertical cabling applications. It is designed to prevent fire from spreading between floors through risers or vertical shafts. The fire resistance requirements for CMR are much stricter than that of CM. And CMR cable is more flame-retardant and consequently more expensive than CM cable.

CMP Cable Jacket

CMP stands for "Communications Multipurpose Cable, Plenum", it is a cable jacket fire resistance rating defined in Article 800 of the NEC. The CMP is the highest grade of ethernet jacket fire rating and complies with the UL 910 plenum test and CSA FT6.

Made from fluorinated ethylene polymer (FEP) insulation and low smoke polyvinyl chloride (PVC) outer sheath, the CMP cables are also referred to as "plenum-rated cable", and are suitable for installation into air plenum spaces like a dropped ceiling or raised floor. CMP cables (plenum-rated cables) can restrict flame propagation to no more than five feet and limit the amount of smoke emitted during a fire and they won't give off toxic fumes when burned due to the more clean and self-extinguish material.

Cat6 CM vs. CMR vs. CMP Cable

CM vs. CMR vs. CMP: What's the Difference?

Now that you already know each ethernet cable jacket type and its fire rating. Let's sum up the differences between the CM cables, the riser rated cables, and the plenum rated cables in the table below.

Jacket Material
low smoke PVC; FEP
UL 1685; CSA FT1
UL 1666; CSA FT4
UL 910; CSA FT6
Fire Rating
Application Scenarios
in wall
plenum places & drop ceiling
cabling on the same floor
non-plenum vertical cabling
raised floors
Cable Price
The cost of CMP cable is much higher than the others.
CM cables cannot replace CMR cables and CMP cables, CMR can be used in any non-plenum spaces indoors, while CMP can alternate all.

Application of CM, CMR and CMP Cable

Given these differences, then how could you choose the appropriate fire rated cable?

CM vs. CMR vs. CMP: Which to Choose?

To maximize cabling performance, it's important to ensure that the type of fire rated cable selected meets the standards outlined for your particular project.

CM cables: a direct connection between devices within a short distance. If you are to use the CM cables on the same floor or use them in residential and commercial buildings, you can choose the CM option.

CMR cables: CMR cables can also be a great choice if you are not required to run cables through air ducts. It can be more cost-effective than CMP and has relatively high safety standards.

CMP cables: CMP cables can be used for any type of cable needs. Meeting the strictest safety standards, the CMP cable can allow peace of mind that if a house fire were to occur, there would be less risk of toxic fumes being inhaled.

Knowing the information about CM, the riser rated cable, and the plenum rated cable, please make a wise choice based on your own needs.

Some Related Terms: CMX, PVC and LSZH

CMX: CMX is also a cable jacket type. Made of LLDPE (Linear Low-Density Polyethylene), cables with the CMX jacket have UV-resistant and weatherproof properties. They are meant to withstand harsh sunlight, wind, rain, and extreme temperature changes. However, they are not fire-rated.

PVC: As mentioned above, PVC is the material that makes up the Ethernet cable jackets with CM, CMR, and CMP ratings. Ethernet cables labeled PVC CM, PVC CMR, or PVC CMP on the jackets are often seen in the market.

LSZH: Low Smoke Zero Halogen cables are built with a jacket material free from halogen for different applications. The LSZH cable is slightly inferior to the Plenum type and is commercialized mostly in Europe.

FS Cable: Ethernet Bulk Cables with CM/CMR/CMP Choices

FS provides various ethernet bulk cables covering Cat5e, Cat6, Cat6a, and Cat7 types. For CM vs. CMR vs. CMP cable jacket ratings, all of the three are available for your different deployment demands. FS bulk cable has innovative craftsmanship to guarantee performance & security and a user-friendly design to optimize your experience for sure. Choose FS ethernet bulk cables, ideal for multiple network applications in offices, hotels, smart homes, data centers, etc. Besides, the outdoor direct burial cables provide you another option to extend your Internet connections even in harsh or extreme environments, perfect for your outdoor or burial installation projects. Find the right cable for your project from FS.

FS Ethernet Bulk Cables

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