Buying Ethernet Cable for your Network

If you are buying Ethernet cable for the first time, focus on these four features and you'll make a good decision. Other factors are worth considering in certain circumstances so if in doubt, read on.

• Speed (Data Rate): the speed of a cable refers to the amount of data it can transmit per second. 100 Mbps means the cable can transmit 100 million bits of data a second. In a commercial network, speed is usually dictated by the equipment you are connecting (for example, a network switch with Gigabit Ethernet ports). In the home, choose a cable that can support the speed of your Internet connection, plus some room for speed upgrades in the future. A cable's Category designation (e.g. Cat5e, Cat6, etc.) is an easy way to identify the speed of a cable. See Table 1: Category Cable Summary for more information.
• Shielding: some Ethernet cables are shielded to protect the cable's conductors from electromagnetic interference (EMI) caused by power lines, large machinery, radio, lighting, etc.. Shielding also prevents parallel conductors inside the cable jacket from interacting with one another. See Ethernet Cable Shielding for more information.
• Cable Length: The maximum length of an Ethernet cable is about 90 meters. Good quality cables with shielding and thicker conductors can reach further but some trial and error will be required. Keep in mind that cable runs are rarely straight so plan on extra cable for some twists and turns. 

Ethernet Cable Categories

The "Cat" in Cat5e, Cat6, etc. is short for "Category." Network cables are divided into categories based mainly on bandwidth (measured in MHz), maximum data rate (measured in megabits per second) and shielding.

• Cat5: Introduced in 1995, Category 5 cable has a data rate of up to 100 Mbps. It is used for standard 10BaseT and 100BaseT (Fast Ethernet) networks, and can distribute data, video and telephone signals at distances up to 100 meters (328 ft.). Cat5e is not an official designation but is used by manufacturers to describe an enhanced Cat5 cable that is capable of speeds up to 1 Gbps. Its higher data rate is achieved by increasing the number of twists, making it more resistant to crosstalk. Cat5e is recommended for new sub-Gigabit network installations.
• Cat6: In comparison to Cat5e, Cat6 cable provides greater bandwidth and data transfer rates up to 1 Gbps over 100 m, the same as Cat5e. However, at shorter distances of up to 37 m (121 ft.), Cat6 is able to achieve 10 Gbps speeds thanks to its improved shielding and higher bandwidth. Cat6 includes a physical separator called a "spline" between the four pairs to reduce crosstalk and foil shielding to reduce electromagnetic interference. Cat6 cabling is backward compatible with the Cat5/5e standard. Introduced in 2009, Cat6a is an "augmented" Category 6 cable with a bandwidth of up to 500MHz.
• Cat7: The Cat7 specification is a proprietary standard developed by a consortium of companies and is not endorsed by IEEE or TIA/EIA. While substantially similar to the performance characteristics of Cat6a, Cat7 cables features proprietary GG45 connectors and robust shielding. Cat7a (Category 7 Augmented) is a further refinement of Cat7, capable of 40 Gigabit speeds over 50 meters and 100 Gbps up to 15 meters. The proprietary nature of the Cat7 and Cat7a standards and lack of support from IEEE and EIA has resulted in a relatively small installed based for Cat7/Cat7a.
• Cat8: With a bandwidth of up to 2 GHz (2000 MHz) over 30 meters and a data rate of up to 40Gbs. Cat8 cable is ideal for switch-to-switch communications in a 25GBaseT or 40GBaseT network. Its conductors are wrapped in foil to virtually eliminate crosstalk and enable higher data rates. The result is a heavier gauge cable that is quite rigid and can be difficult to install in tight spaces. When it uses RJ45 connectors, it is backwards compatible with previous standards. Cat8 is the go-to choice for high-performance applications such as data centres, server rooms, and other high-density environments. Despite its many network performance advantages, Cat8 is not without its drawbacks. Its limited distance range is a major obstacle, with its high-speed data transfer only possible over a channel distance of up to 30 metres. Moreover, the cost of Cat8 cable is significantly higher than that of older cable types like Cat6, making it less practical for smaller or less demanding networking applications. Adding to the complexity, Cat8 introduces connector confusion, as four types are available and ratified by either ANSI/TIA or ISO/IEC. While ANSI/TIA Cat8 and ISO/IEC Cat 8.1 (Class 1) use the more common ‘RJ45’ connector and are fully backward compatible with Cat5/5e and Cat6/6A, ISO/IEC Cat8.2 (Class 2) utilises either TERA, ARJ45, or GG45 (GigaGate 45) connectors, which are different but technically superior to the RJ45, as they relocate the pins to move the pairs further apart in the connector, thereby reducing crosstalk. Despite its advantages in terms of speed and bandwidth, Cat8 Network cable is typically only recommended for high-performance applications such as data centres, server rooms, and other high-density environments. It is important to carefully consider the distance requirements, cost, termination, and equipment needs of your networking application before choosing to use Cat8. For some applications, fibre optic connections may be a more cost-effective solution.

What type of Ethernet cable should I buy for my home network?

Even with a speedy WiFi6 router, your connection to the Internet is usually the bandwidth bottleneck. Currently, the fastest Internet plans available from the major carriers offer download speeds of 1 gigabit per second (1,000 Mbps). If you already have the fastest Internet access available from your provider, use Cat6a cable. This will give you some headroom for future speed increases. For Internet download speeds up to a gigabit, Cat5e is a good choice. You'll save a little money over Cat6a and the thinner cable will be easier to install.

Ethernet Cable Length

The further a signal has to travel along a cable, the more it will degrade (a process known as attenuation) until it reaches the point where it can no longer be detected, or is too distorted to be interpreted by the receiving device. Attenuation can also be caused by noise due to electrical currents and radio frequencies. Cables with shielding to minimize noise will work reliably over greater distances.

The maximum length of a Cat5e or Cat6 Ethernet cable is about 295 ft. (90 m), plus up to 16 ft. (5 m) of patch cable on either end, for a total of 328 feet or 100 meters. Beyond this, the signal begins to degrade, reducing the speed and reliability of the connection. Good quality cable can support runs in excess of 100 meters but data transmission speed may be reduced. Higher data rates can also be achieved over shorter distances.

Ethernet Cable Shielding

Cable shielding is a layer of material that is wrapped around the wires inside a cable to reduce interference and improve signal quality. The shielding helps to prevent external electromagnetic interference (EMI) and radio frequency interference (RFI) from affecting the data transmission over the cable.

Shielded Ethernet cables can employ two types of shielding:

• Conductor Shielding protects each twisted pair using aluminum foil or braided wire strands
• Cable Shielding wraps all twisted pairs in aluminum foil or braided wire strands