Beginner's Guide to Network Cables

Written by Don Schultz, trueCABLE Senior Technical Advisor, Fluke Networks Copper/Fiber CCTT, BICSI INST1, INSTC, INSTF Certified

 In today's digital landscape, where connectivity reigns supreme, understanding the nuances of network cabling is paramount. Whether you're setting up a home network or managing a complex enterprise system, the right cabling solution can make or break your data transfer efficiency. The choice of what communications cable (and where) to use can be extremely confusing. This guide aims to demystify the world of network cables, equipping you with the knowledge to make informed decisions and ensure seamless communication across your digital ecosystem.

Understanding the Fundamentals of Network Cabling

Ethernet is not a cable. Ethernet is a protocol. The Ethernet protocol defines how data is transmitted between one device and another on a wired LAN or WAN. Physical cable started with coaxial many decades ago and now fiber optic cabling is becoming very popular. For the most part, however, wired LANs typically use purpose constructed copper twisted pair Category cable to transmit these Ethernet signals. This is how the term “Ethernet” became conflated with the generic term of “Ethernet cable”. It is understandable, as for more than 30 years the common go-to for Ethernet connectivity has been the copper twisted pair category cable.

Network cabling serves as the backbone of any wired connectivity infrastructure, facilitating data transmission between various devices. These cables come in different types, each designed to cater to specific requirements and applications. At the core of network cabling lies the Ethernet cable, a twisted pair of copper wires that enables point-to-point or wide-area network connections.

Copper twisted pair Ethernet cabling has evolved over the years, with each iteration offering improved performance and capabilities. From the early days of Category 3 (Cat3) cables to the current industry maximum of Category 8 (Cat8), these cables have become increasingly adept at handling higher data transfer speeds and minimizing electromagnetic interference.

Exploring Alternative Network Cable Types

 While copper twisted pair Ethernet cables are the most prevalent in wired networking, it's essential to be aware of alternative cable types that may cater to specific applications or environments. One is old and one is the future.

• Coaxial Cables: Widely used in cable television (CATV) and broadband Internet installations, coaxial cables offer superior shielding against electromagnetic interference. However, they are gradually being replaced by twisted pair cables in most networking applications. See Coaxial vs Ethernet cable - What's the Difference? for more information.

Example of coax cable with F-connector

• Fiber Optic Cables: Offering unparalleled data transfer speeds and immunity to electromagnetic interference, fiber optic cables are the preferred choice for high-bandwidth applications and long-distance data transmission. They are commonly used in backbone networks and data centers. That said, fiber optic cabling is finding its way into the home (FTTH) at a rapid pace due to higher data speed demands. This is largely driven by an increasing need for high-definition (HD) video applications. See Fiber Optics In The Home - Why and When?

Example of fiber optic cable

While copper twisted pair Ethernet cables remain the primary choice for most residential and commercial networking applications, understanding the capabilities and use cases of alternative cable types can help you make informed decisions for your specific networking needs. As such, we will discuss copper twisted pair cabling in depth! Starting with…

Deciphering the copper Ethernet Cable Categories

When shopping for Ethernet cables, you'll encounter various categories, each denoted by a "Cat" designation followed by a number. This categorization system is designed to help you identify the cable's performance capabilities and suitability for your network needs.

• Category 3 (Cat3): Still recognized in the ANSI/TIA standard, Cat3 was previously used for 10 Mbps networking and voice communications. Very few, if any, installations are seeing Cat3 installed today. At best, Cat3 may be run to repair existing old infrastructure. You are not likely to encounter it.
• Category 5 (Cat5): Once a widely adopted standard for data networking, Cat5 cables are now considered obsolete for modern applications. They support data transfer rates up to 100 Mbps and are suitable for very basic network connections. Any installation wired with Cat5 should be retrofitted with Cat5e or higher for modern networking requirements.
• Category 5e (Cat5e): An enhanced version of Cat5, Cat5e cables handle gigabit Ethernet speeds up to 2500 Mbps (2.5 Gbps). While still in use, they are gradually being phased out in favor of more advanced alternatives.
• Category 6 (Cat6): The current industry standard, Cat6 cables are designed to support data transfer rates up to 10 Gbps over a maximum distance of 55 meters. Up to 100 meters Cat6 is ideal for 5 Gbps. Cat6 offers improved crosstalk and interference protection, making them ideal for high-bandwidth applications. It should be noted that some manufacturers label their cables as “Cat6E”. No such Category exists and this is deceptive marketing. Any manufacturer labeling their cabling with faux Categories should be avoided. What else are they being deceptive about?
• Category 6A (Cat6A): Offering superior performance, Cat6A cables can reliably transmit data at speeds up to 10 Gbps to the full 100 meters that any Category of Ethernet can be run. Cat6A features enhanced alien crosstalk prevention techniques and makes Cat6A an excellent choice for demanding network environments.
• Category 7 (Cat7) and Category 8 (Cat8): These cutting-edge cable categories are primarily used in data centers and high-performance computing environments, supporting data transfer rates of up to 40 Gbps for very limited distances, otherwise they are equivalent to Cat6A. It should be noted that Cat7 is not an ANSI/TIA standard, and is instead recognized by ISO/IEC outside of North America. Cat8 is the North American equivalent.

When selecting the appropriate cable category, consider your: 

• Current and future network requirements
• Bandwidth demands
• Distances over which data needs to be transmitted

It's generally recommended to future-proof your network by opting for a higher category cable, ensuring seamless scalability as your needs evolve. This should be done within reason, however. Certain installations may never need anything more than Cat6 (PoE surveillance cameras for example). Cat6A may be a better choice than Cat8, as Cat8 is nothing more than Cat6A past 98 feet. Installing Cat8 would cost more money and add additional installation challenges while getting you nothing. In short, more money does not necessarily mean better performance! Incidentally, if you are considering Cat8 you are likely better served with fiber optical cable, which we will discuss later.

Solid or Stranded: Understanding Cable Construction

Ethernet cables are available in two primary wire configurations: solid and stranded. While both serve the same purpose of transmitting data, their construction and intended applications differ.

• Solid Cables: As the name suggests, solid cables use eight solid insulated copper conductors, twisted into four pairs. These cables are known for their durability, heat dissipation, and longer data transmission capability. Solid copper conductors trade away flexibility as this type of cable is not designed for frequent handling. This is the type of cabling typically used for permanent installations, such as in-wall or under-floor wiring.
• Stranded Cables: Similar to solid copper conductors, stranded copper conductors are constructed of fine copper hairs and then insulated into four twisted pairs of eight conductors. This construction provides increased flexibility, making them suitable for applications where frequent movement or bending is expected, such as patch cables connecting devices to wall outlets. Stranded copper cabling trades data transmission distance and heat dissipation for flexibility.

When planning your network cabling, consider the installation environment and potential for cable movement. Solid cables are ideal for fixed, long-term installations, while stranded cables offer greater flexibility and are better suited for interconnecting devices or temporary setups.

Don’t construct frequently handled patch cords with solid copper Ethernet cable. Too many issues can occur at the terminations due to how 8P8C connectors are designed. See Choosing the Right Termination - Keystone Jack vs RJ45 Connector vs Field Termination Plug for more information on the correct terminations and how to build a structured cabling system correctly.

Shielded or Unshielded: Protecting Against Interference

Electromagnetic interference (EMI) can be a significant concern in network cabling, potentially causing data corruption or signal degradation. To mitigate this issue, Ethernet cables are available in both shielded and unshielded varieties.

• Unshielded Twisted Pair (UTP or U/UTP): As the name implies, unshielded cables do not have any additional shielding around the twisted pairs. Be aware that the UTP twist rate already imparts a shielding effect negating much external EMI/RFI. While cost-effective, they may be more susceptible to EMI, particularly in environments with high levels of electromagnetic radiation.

Example of Unshielded Twisted Pair Ethernet Cable

• Shielded Twisted Pair (F/UTP, FTP, and STP): Shielded cables incorporate a conductive shielding layer, typically a braided or foil shield (or both), around the twisted pairs. This shielding helps to reduce EMI and crosstalk, making STP cables a better choice for environments with potential interference sources. Shielded cabling comes in many different varieties. Please see Ethernet Cable Shielding Types for more information.

Example of Shielded Twisted Pair Ethernet Cable

When deciding between shielded or unshielded cables, consider the level of EMI present in your installation environment. Shielded cables are recommended for:

• Industrial settings
• Areas with high electromagnetic radiation (certain medical settings)
• Locations near potential interference sources like motors or electrical equipment

For residential or low-EMI environments, unshielded cables are typically more than adequate.

Installing shielded Ethernet cable requires a great deal more attention to detail. Often presenting installation challenges such as reduced flexibility, increased termination difficulty, weight, and the need to bond the cable shield to your AC system ground, the decision to install shielded Ethernet cable should not be taken lightly!

Cable Jacket Ratings: Ensuring Safety and Compliance

Ethernet cables are designed with different jacket ratings to ensure safety and compliance with building codes and regulations. These ratings determine the cable's suitability for various installation environments and applications.

• CM or CM/G (Communications Multipurpose): CM-rated cables are suitable for indoor use in residential and commercial settings. They are the most basic cable jacket rating and do not provide any fire resistance.
• CMR (Communications Multipurpose Riser): CMR-rated cables offer fire resistance and are designed for use in vertical cable runs, such as risers or shafts, where fire safety is a concern.
• CMP (Communications Multipurpose Plenum): CMP-rated cables are the most stringent jacket rating, designed for use in air handling spaces like plenums or air ducts. These cables produce minimal smoke and toxic fumes in the event of a fire, ensuring safety in critical areas.
• CMX (Communications Multipurpose Outdoor): CMX-rated cables are designed for outdoor installations, offering protection against UV radiation, moisture, and extreme temperatures.

When planning your network cabling installation, ensure compliance with local building codes and regulations by selecting the appropriate cable jacket rating for your specific environment and application.

Choosing the Right Ethernet Cable: Other Factors to Consider

With a myriad of options available, selecting the right Ethernet cable can be a daunting task. To help you make an informed decision, consider the following factors:

1. Network Speed Requirements: Assess your current and future bandwidth needs to determine the appropriate cable category. Higher categories support faster data transfer rates but may come at a higher cost.
2. Distance Limitations: Different cable categories have varying distance limitations for reliable data transmission. Ensure that the cable you choose can support the required distances in your network layout. Be aware that temperature can greatly affect your distance limitations in any given installation environment. See Temperature's Effect on Ethernet Cable Length.
3. Installation Environment: Consider the level of electromagnetic interference, potential for cable movement, and environmental conditions (indoor, outdoor, plenum spaces) to select the appropriate cable construction and jacket rating.
4. Future-proofing: While it's tempting to opt for a cable that meets your current needs, consider future-proofing your network by choosing a higher category cable that can accommodate evolving bandwidth demands.
5. Budget: While high-performance cables may offer superior capabilities, they often come at a higher cost. Strike a balance between performance and budget constraints to find the most cost-effective solution for your needs.

By carefully evaluating these factors, you can select an Ethernet cable that not only meets your current requirements but also provides a solid foundation for future growth and scalability.

Installation Best Practices: Ensuring Optimal Performance

Proper installation is crucial to ensuring the optimal performance and longevity of your network cabling system. More installations have been ruined by poor installation practices than any other factor. A well constructed Cat5e structured cable system will massively outperform a poorly constructed Cat6A structured cable system!

Here are some best practices to keep in mind:

• Avoid Sharp Bends and Kinks: Sharp bends or kinks in the cable can cause damage and signal loss, compromising data transmission. Always follow the recommended bend radius guidelines for your cable type. For guidelines that address trueCABLE’s specific bend radius guidelines in addition to generic guidance please see Obey the Bend: Bending Radius of Cable.
• Maintain Proper Cable Termination: When terminating Ethernet cables, it's essential to follow standardized wiring schemes to ensure compatibility and proper data transmission. The two most common wiring standards are T568A and T568B, which define the specific order and color coding of the individual wires within the cable. While both standards are widely accepted and compatible with most networking equipment, it's crucial to maintain consistency throughout your installation. Mixing wiring standards within the same network can lead to connectivity issues and performance degradation. When installing your network cabling, choose either the T568A or T568B standard and adhere to it consistently across all cable terminations, patch panels, and wall outlets. Clearly documenting and labeling your chosen wiring standard can also facilitate future maintenance and troubleshooting efforts. For more specific information about T568A vs T568B please see T568a vs T568b: Which To Use.
• Use Cable Management Solutions: Implement cable management solutions, such as cable trays, raceways, or cable ties, to organize and protect your cables from physical damage or excessive bending. Avoid the use of nylon ties to bundle cables. Much preferred are Velcro (hook and loop) straps for this task, even outdoors.
• Use service loops to address adds/changes and termination corrections at the head and remote ends of your installation. Service loops are often overlooked and should be accounted for in run (drop) length in addition to any “oops” factors you are figuring into your calculations. See Service Loops: Discovering Purpose, Placement, and Preparation.
• Test and Certify Your Installation: After installing your network cabling infrastructure, it's essential to perform thorough testing and certification to ensure optimal performance and identify any potential issues. Cable testers and certification tools are specialized devices that verify the integrity of your cabling system, checking for proper wiring, continuity, and adherence to performance standards. Professional-grade cable testers, such as those from reputable brands like Fluke, can provide detailed test reports for each cable run, indicating pass or fail results based on industry standards. This is a complex topic and not everyone has access to (or can afford) a Fluke certification device. There are workable ways around this issue. Please see Testing 10 Gigabit Ethernet Over Copper on a Shoestring Budget.
• Label and Document Your Cabling: Properly label and document your cabling system to facilitate future maintenance, troubleshooting, and upgrades. Nobody wants to be guessing at which run is what! Please see How To: Dressing Ethernet Cables into Patch Panels for more information.

By following these best practices, you can maximize the performance and lifespan of your network cabling infrastructure, ensuring reliable and efficient data transmission throughout your network.

Establishing a Centralized Network Hub: The Concept of Node Zero

In a well-designed network cabling infrastructure, it's essential to establish a centralized location known as "Node Zero." This location serves as the convergence point for all network cables running throughout your home or office. In the commercial space, this is referred to as a TR or telecommunications room. Businesses may have many TRs, with one or more per floor in multi-story buildings being quite common. This centralized aggregation point is typically seen with networking racks and patch panels. This can take many forms depending on the scope of your installation. In a residential example, this could be under the basement stairs out of the way in a dust proof enclosure. See Advanced Residential and Small Business Physical Ethernet LAN Setup for just how that looks.

By centralizing your network cabling, you can simplify cable management, facilitate future expansions or modifications, and ensure a more organized and efficient network infrastructure.

Ideally, your “Node Zero” should be a well-ventilated area, easily accessible for cable runs, and free from excessive heat, moisture, or other environmental hazards. Common locations include utility rooms, closets, or dedicated network cabinets.

Determining the Optimal Number of Network Cables per Room

When planning your network cabling layout, one crucial consideration is determining the appropriate number of network cables to run to each remote room. While there is no one-size-fits-all answer, there are ANSI/TIA recommendations. In particular, TIA 570-D (the residential standard) provides some guidance on outlets per room. See Life Easier: ANSI/TIA 570-D Residential Communications Cable Best Practices Explained for more information.

Generally, several factors should guide your decision:

• Room Type and Purpose: Evaluate the specific needs of each room based on its intended use. For example, a home office or media room may require more network connections than a bathroom or utility room.
• Current and Future Needs: Consider not only your current network device requirements but also potential future expansions or additions. It's generally advisable to install more cables than you currently need to accommodate future growth. The standard currently recommends two runs per room at a minimum (for copper twisted pair).
• Ease of Installation: If running additional cables in a particular room is relatively straightforward, it may be prudent to install extra cables during the initial installation to avoid disruptions and additional work in the future.

A common approach is to install two network outlets on the opposite side of the wall cavity from the electrical outlet, as network devices often require both power and network connectivity. Opposite side installation (approximately 16” separation) absolutely ensures you maintain your distance from AC power induced EMI sources, which is important. For high-demand areas like home offices or media rooms, you may want to consider installing additional outlets or running spare cables for future flexibility.

Implementing a Patch Panel: Simplifying Cable Management

Patch panels come in a number of varieties. Please see Punch Down, Feed-Through, and Toolless Keystone Ethernet Patch Panels Explained to get an idea of what is available. Patch panels are a core component of structured cabling systems, and this is known as rack to jack. trueCABLE recommends patch panels when possible, and definitely when 12 or more runs are involved. In larger or more complex network installations, a patch panel is all but required for your cabling infrastructure. Patch panels are centralized termination points where permanent "building wiring" cables from various locations converge, allowing for easier cable management and interconnections.

By terminating the building wiring cables on the patch panel, you can use shorter, more flexible Ethernet patch cables to connect devices or switches to the appropriate ports. Similarly, the remote run locations are terminated to keystone jacks and patched into with patch cords as well. This modular approach simplifies cable organization, facilitates moves, additions, or changes, and provides a cleaner, more structured cabling environment. 

Primary advantages of patch panels:

• Let you organize your cables into one place
• Permits easier cabling labeling and documentation
• May increase performance by suppressing ANEXT (alien crosstalk) between cables, especially with Cat6A pushing 10 Gbps
• Allows for easy bonding and grounding of shielded cables
• Utilizes the IDC (Insulation Displacement Contact) style of termination such as punch downs or keystones that greatly increase network reliability, dramatically reducing termination induced communications issues

While not strictly necessary for very small residential networks, a patch panel can be a worthwhile investment for those seeking a more organized and scalable cabling solution.

Pro Tip: A shielded tool-less keystone patch panel can easily accept unshielded Ethernet cable in addition to other types of communications cable such as fiber optic and even coaxial, HDMI, BNC, and RCA couplers. This is what is known as a “multimedia patch panel”. If shielded runs are required, then shielded keystone jacks are used and the shielded patch panel should be grounded (called bonded to ground). This won’t affect your unshielded keystone jacks and cabling. This is of particular use for residential and small business installations where mixed media types are common.

Summing Up…

If you want to learn more about fiber optic or Ethernet technologies, please check out the rest of our Cable Academy! Our online learning platform provides comprehensive resources and training materials to help you gain a deeper understanding of these technologies and make informed decisions. Visit our Cable Academy today to learn more about our fiber optic products and services.