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Want to know the difference between CM vs CMR vs CMP Ethernet cables? This guide will explain their fire resistance levels and ideal applications, helping you choose the right cable for your needs
What are Ethernet Cable Jacket Ratings?
Ethernet cable jacket ratings classify safety and performance, as specified by the National Electric Code (NEC). These ratings ensure the safe and proper use and installation of Ethernet cables in various environments. The letters CM, CMR, and CMP represent different types of cable jacket ratings, each indicating varying levels of fire resistance and safety for different applications.
CM cable jackets refer to the outer covering of Communications Multipurpose rated cables, typically made from PVC. They are cost-effective but have potential safety concerns regarding smoke and gas emissions during a fire.
These ratings determine where Ethernet cables can be safely installed. From residential setups to complex commercial installations, knowing the right type of cable jacket rating can maximize cabling performance and ensure compliance with safety regulations.
Here’s a breakdown of what these ratings mean and how they are applied.
Common Ethernet Cable Jacket Ratings: CM, CMR, and CMP
The three main types of Ethernet cable jacket ratings are CM (Communications Multipurpose), CMR (Communications Riser), and CMP (Communications Plenum). Each rating designates Ethernet cables for specific uses based on their fire resistance properties. CM cables, for example, are made from polyvinyl chloride (PVC) and are most commonly used as general-purpose communication cables suitable for non-plenum areas.
CMR cables, on the other hand, are designed for vertical spaces like risers and have stricter fire resistance requirements than CM cables. CMR cable jackets are made from materials like low-smoke PVC or fluorinated ethylene polymer and are designed to prevent fire spread between floors, making them ideal for multistory buildings.
Lastly, CMP cables are designed for use in ventilation spaces, such as air ducts, and have the highest level of fire resistance to meet stringent safety standards. Plenum-rated cables are crucial for areas with air circulation like dropped ceilings and raised floors due to their strict regulations regarding flame propagation, smoke emission, and toxicity.
To determine the jacket rating of an Ethernet cable, check for printed markings along the cable sheath, which typically include its UL listing and fire safety rating, such as CM, CMR, or CMP. These designations, certified by Underwriters Laboratories (UL), indicate the cable's compliance with fire safety standards, with CMP being the highest-rated for plenum spaces.
Knowing these common cable jacket ratings helps in choosing the right cable for your specific needs. Whether you need a basic cable jacket for general use or a safer CMP cable for high-risk areas, understanding the differences between CM, CMR, and CMP will ensure you make the best choice for your installation, including the use of a CMP cable jacket.
What is a CM-Rated Ethernet Jacket?
CM cables, or communications multipurpose cables, are suitable for general use in standard, non-plenum areas. Made from polyvinyl chloride (PVC), they must pass a standardized flammability test to receive their rating. While CM cables have basic fire-resistance properties, they meet minimal safety standards, making them the most basic cable jacket rated for general use.
Primarily used for horizontal wiring within a single floor or area, CM cables are ideal for running cables in walls or rooms where fire ratings aren’t strict, such as in single-story residences. CM cables offer a cost-effective solution for residential installations, providing adequate safety and performance without the need for higher fire resistance.
Unless otherwise specified, most Cat6 and Cat6a Ethernet cables are CM-Rated, meaning they are generally safe for your home.
What is a CMR-Rated Ethernet Jacket?
CMR cables, or Communications Riser cables, are designed for vertical spaces and have stricter fire resistance requirements compared to CM cables. Made from materials like low-smoke PVC or fluorinated ethylene polymer (FEP), these cables enhance fire-resistant properties. CMR cables prevent fire from spreading between floors, making them ideal for vertical installations in multistory buildings.
CMR Ethernet cables are suitable for vertical installations in multistory buildings due to their material composition and fire resistance capabilities. CMR-rated cables can replace CM-rated cables, providing more fire resistance for vertical installations. While they cannot be used in plenum spaces, they offer a higher level of safety for vertical runs, making them a versatile and essential component in multistory building installations.
What is a CMP-Rated Ethernet Jacket?
CMP cables, or Communications Plenum cables, are designed for use in air circulation spaces, such as the areas above ceilings or below-raised floors where air handling occurs. With the highest level of fire resistance among Ethernet cable ratings, they produce minimal smoke and toxic gases when burned, making them ideal for environments requiring strict safety measures.
Typically made from low-smoke PVC or fluorinated ethylene polymer (FEP), CMP cables are constructed to emit minimal toxic fumes, which is vital given the airflow within these environments. Their design ensures enhanced safety and compliance with the highest fire safety standards, making them the best choice for plenum spaces.
Comparing CM, CMR, and CMP Ethernet Cable Jackets
Comparing CM, CMR, and CMP cables reveals significant differences in fire resistance, usage scenarios, and cost. CM cables, made from relatively inexpensive polyvinyl chloride (PVC), offer basic fire-resistance properties and are ideal for non-plenum areas in single-story buildings.
CMR cables, with higher flame retardance, are designed to prevent fire spread between floors, making them suitable for vertical installations in multistory buildings.
CMP cables stand out with the highest fire resistance, producing minimal smoke and toxic fumes when burned, making them essential for air circulation spaces like those above ceilings and below raised floors. The cost of these cables reflects their fire resistance properties, with CM cables being the most cost-effective, CMR cables moderately priced, and CMP cables the most expensive due to their advanced safety features.
Fire Resistance and Safety Standards
Ethernet cable jacket ratings help in assessing a cable’s fire resistance and safety based on where it will be used. These ratings are crucial for compliance with safety standards, such as those specified by the National Electric Code (NEC). CMP cables, for instance, must pass rigorous tests to meet these standards, ensuring they produce minimal smoke and toxic fumes during a fire.
The construction of CMP cables emphasizes low smoke emission to enhance safety in case of fire. In contrast, CMR-rated cables, made from low-smoke PVC or fluorinated ethylene polymer, inhibit fire spread between floors but can still emit some smoke and toxic halogens when burned.
CM cables have the lowest fire resistance, suitable only for areas with minimal fire risk.
Usage Scenarios and Applications
CMP cables are more commonly recommended for various cable needs due to their highest fire resistance and safety in plenum spaces, where air handling occurs. These cables are essential in commercial and industrial environments where stringent fire safety measures are required.
For home installations, CMR cables are often recommended for their enhanced fire protection, especially in multistory residences. CMR cables can be used in place of CM cables, offering more versatility for different installations without compromising safety.
While CM cables are adequate for basic residential use, CMR cables provide a safer and more reliable option for complex setups. If you're installing an Ethernet cable in your home because you are upgrading to a wired gaming connection or a wired streaming connection for your TV, then a CM-Rated Ethernet cable will usually suffice.
Cost Considerations
CMP-rated cables are generally the most expensive due to their enhanced fire safety features. The specialized manufacturing and materials used in CMP cables, such as low-smoke PVC or fluorinated ethylene polymer, contribute to their higher cost. However, this investment can be justified by the increased safety and compliance with stringent fire codes.
While CMR cables are more affordable than CMP cables, they still offer significant fire resistance, making them a cost-effective choice for vertical installations. CM cables, being the least expensive, are suitable for standard, non-plenum areas where fire risk is minimal.
Balancing cost and safety needs is essential when choosing the right Ethernet cable for your installation.
Choosing the Right Ethernet Cable Jacket for Your Needs
Choosing the right Ethernet cable is crucial for ensuring the safety and optimal performance of your network. When selecting Ethernet cables, consider factors such as safety, performance requirements, and budget constraints. The category of an Ethernet cable, such as Cat 5e or Cat 6, is key to determining its speed and bandwidth capabilities.
Understanding the differences between CM, CMR, and CMP cables will help in making an informed decision based on specific needs. Whether setting up a home network or a complex commercial installation, choosing the right cable ensures efficient and safe network performance.
Residential Installations
CMR cables are typically adequate for home runs, offering a good balance of safety and performance for residential applications. Suitable for non-plenum spaces, they are a versatile option for standard installations. Routing CMR cables through walls and floors in residential setups ensures safety and performance without needing higher fire resistance.
CMR cable is adequate for most home applications. However, it is not suitable for use in air ducts. For single-story residences, CM cables might also be a cost-effective choice, given the minimal fire risk involved.
Commercial and Industrial Installations
In commercial and industrial environments, selecting the right cable ensures performance and safety. CMP cables are preferred for applications where fire safety is critical, such as in plenum areas where air handling occurs. These cables provide the highest level of fire resistance and compliance with stringent safety standards.
CMP cable is generally recommended for any cable needs, especially in demanding environments. Investing in CMP cables ensures maximum safety and minimal risk, making them the best choice for commercial and industrial installations.
Frequently Asked Questions
What are Ethernet cable jacket ratings?
Ethernet cable jacket ratings indicate the fire resistance and safety standards of the cables, as classified by the National Electric Code (NEC). Understanding these ratings is crucial for ensuring compliance and safety in installations.
What is the difference between CM and CMR cables?
CM cables are intended for non-plenum areas, whereas CMR cables are specifically designed for vertical spaces and offer enhanced fire resistance to limit fire spread between floors.
Why are CMP cables more expensive?
CMP cables are more expensive because they offer superior fire resistance, including low smoke emission and minimal toxic fumes, which makes them suitable for use in plenum spaces.
Can CMR cables be used in place of CM cables?
Yes, CMR cables can replace CM cables as they provide enhanced fire resistance and versatility for various installations.
What cable should I use for my home network?
For your professionally installed home network, it is advisable to use CMR cables, as they offer a suitable balance of safety and performance. In non-plenum areas of a single-story residence, CM cables may also suffice.