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How to Choose the Right Cat6a Cable for Your 10G Networks

November 11, 2015

The dramatic growth in data center throughput has led to the increasing usage and demand for 10G network. Category 6a, also named Cat6a cable, is currently the preferred Ethernet cable designed to meet and exceed the requirements for the next generation 10GBASE-T applications. At present, there are various types of Cat6a network cables like UTP, S/UTP, F/UTP and SFTP. Which one is best suitable for 10GBASE-T network? And other considerations will be given in this article too.

What Is Cat6a Cable?

Cat6a Ethernet cable uses four twisted cables and is typically terminated with RJ45 connector in patch cord. It is defined by ANSI/TIA-568-C.2, which can support 10GBASE-T up to 100 meters in channel length which ensure that it can support the fasted Ethernet applications. Cat6a extends electrical specifications to 500 MHz from 250 MHz for Cat6 cable. And it is also backwards compatible with Cat5e patch cable and Cat6 patch cable.

cat6a cable

A new electrical parameter measure of Alien Crosstalk (ANEXT) was introduced to ensure that the Cat6a cabling system can properly run 10 Gigabit transmission, which was initially not a concern for Cat5e and Cat6 whose frequency was up to 100MHz and 250MHz respectively. However, due to operating at a higher frequency of 500MHz for Cat6a, it is important to consider the alien crosstalk effect. The amount of ANEXT depends on a number of factors, including the type of cable, cable jacket, cable length, cable twist density, proximity of adjacent cables and connectors, and EMI (Electro Magnetic Interference). Patch panels and connecting hardware are also affected by ANEXT.

Cat6a Cable for 10GBase-T: UTP vs F/UTP vs SFTP

Cat6a patch cable has been extensively tested and has been proven to support 10GBASE-T networks with plenty of headroom. And there are many types of Cat6a cables which are added different protection materials. Here is a table showing different types of copper Ethernet cables.

UTP cat6a cable
Unshielded Twisted Pair UTP Ethernet cable comprises pairs of twisted wires. It is one of the most basic ways used to help prevent electromagnetic interface.
F/UTP cat6a cable
Shielded Twisted or Foiled Twisted Pair S/UTP and F/UTP network cable have an overall foil or braid screen encasing the 4 pairs of unshielded twisted pairs.
SFTP cat6a cable
Shielded and Foiled Twisted Pair A combination of S/UTP and F/UTP, SFTP cable owns foil shielding around the individual twisted wires and an overall screen which can sometimes be a flexible braid.

With features like extra internal airspace between the twisted pairs, Cat6a UTP cable can minimize crosstalk and ANEXT in 10GBASE-T networks. But the effects of ANEXT do not be eliminated. Therefore, ANEXT measurement is essential for Cat6a UTP cable, which is quite complex and time-consuming.

Cat6a S/UTP or F/UTP cable is better than UTP cable in some degree. The foil shield acts as a barrier reflecting the noise from machinery, lights, motors, and other sources of EMI and RFI. And the foil shield also can protect the data signals from leaking out of the copper cable. In addition, CAT 6A F/UTP cable does a much better job of eliminating ANEXT than CAT 6A UTP, providing significantly more headroom for 10GbE over copper.

Compared with Cat6a UTP and F/UTP cable, Cat6a SFTP patch cable provides the maximum level of protection from interference and is found in the highest performance cables. With the double shield, Cat6a SFTP cable allows for the fastest and stable transmission for 10GBASE-T networks. Furthermore, the additional foil on individual pairs can limit the amount of crosstalk and ANEXT effectively. And Cat6a SFTP patch cable is prevalent in many types of applications like government, healthcare and education.

What Else You Should Consider When Choosing Cat6a Cable?

Besides knowing to choose from Cat6a UTP, F/UTP and SFTP cable, some other parameters of Cat 6A cables also affect its performance. Here are four key considerations to weigh when choosing a Cat 6A cable.

Cat6a cable

Cable Size and Weight

Cat6a cable operates at frequencies up to 500 MHz—twice than that of Cat 6. Controlling noise and crosstalk at higher frequencies has required Cat6a cables up to 50% larger than their Cat 6 predecessors. Larger size means fewer cables can fit into a cable tray or conduit, which is a huge concern in retrofit installations. While many available Cat6a options remain significantly larger and heavier, the newest Cat6a cables are only about 15 percent larger than Cat 6.

Bend Radius

Larger cable diameters mean a larger bend radius which is important when routing cables in tight spaces such as inside wall cavities. The bend radius also affects the ability to route cables for maximum airflow within racks. The smaller the bend radius, the easier the cable is to route and install.

Installation Complexity

Most Cat6a Ethernet cables are larger because they have more and thicker materials. More twists in the copper pairs, larger splines separating the pairs, and thicker outer jackets. All of these lead to longer time to prepare and terminate Cat6a cables. Thinner and more round cables take less time to install.

EMI Shielding

There is a perception that shielded cable provides better noise immunity, but the effectiveness of the shield depends on the quality and reliability of the shield termination, balance of the twisted pairs, and quality of the local and remote ground connection. The impedance of the ground connection can increase higher frequencies and differences in ground potential can couple noise into the conductors. Cable designs that effectively surround the conductors with a Faraday cage can provide an electromagnetic barrier without the potential drawbacks of grounding.


Before deciding on the best Cat6a cable, all factors need to be weighed up so that the Cat6a Ethernet cable you buy is future-proofing for your 10GBASE-T networks. Cat6a UTP, S/UTP, F/UTP and SFTP cables are available for 10GBASE-T. But the SFTP Cat6a patch cable, with better performance, has more advantages over other types Cat6a cables in 10GBASE-T networks.

Related Article: Cat6a Shielded vs. Unshielded: Which Is Better? Quick View of Ethernet Cables Cat5, Cat5e And Cat6

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