Bulk Cat6 Cable – STP vs UTP

30/09/2015 0 Comment(s) Bulk Ethernet Cable,

Bulk cat6 cables, otherwise known as category 6 cables, is used as the cabling infrastructure for Ethernet (10BASE-T), Fast Ethernet (100BASE-TX), Gigabit Ethernet (1000BASE-T), and 10-gigabit Ethernet (10GBASE-T), and provides performance of up to 250 MHz. The cat6 cable is backward compatible with cat5 and cat5e cabling since it consists of four unshielded twisted pairs (UTP) of copper wire that terminates with the RJ45 connectors that use either T568A or T568B pin assignments.

The Cat6 standard supports higher performance compared with the cat5 and cat5e specifications, and the specifications for the reduction of crosstalk and system noise are more stringent. It is expected to eventually supersede cat5 and cat5e cabling in the future, though the older cable types continue to be popular for use in network installations.

Some users of cat6 cable advocate the use of UTP, while others prefer STP (screened twisted-pair) because of its superiority in shielding the system from electromagnetic interference. However, it is best to look at the differences between STP and UTP before choosing one over the other.




Ethernet cables consist of four pairs of twisted wires that are enclosed in a single insulating cover jacket. The twists in each pair of wire cancel out electronic magnetic interference (EMI) that may develop in the wiring. Both STP and UTP provide reliable connectivity of electronic equipment, but the quality of the transmitted signals can differ depending on the environment where the cables are installed. STP and UTP wires are similarly constructed from twisted pair of wires, with the STP having an additional shielding material that serves to cancel any external interference from around its path or environment.

Unshielded Twisted Pair (UTP) Cable

The unshielded twisted pair cable is the most common cable used, from category 3 to category 6 Ethernet cables. Though considered inferior to STP because of its inability to shield the system from interferences, it is used quite frequently in installations for home and office networks.

The UTP cable relies on balancing and filtering techniques to block out electromagnetic interference (EMI). It employs media filters, baluns, or a combination of both. The term balun comes from the combination of the words balanced and unbalanced, and refers to a device that joins a balanced line to an unbalanced line. It converts an unbalanced signal to a balanced signal or vice versa, and provides a balance output by isolating transmission lines. Thus, noise that is induced in two conductors such as the twisted pair of wires is cancelled out at the receiving end. Users of UTP avoid the shielding and grounding issues associated with STP.

Compared with shielded cables, UTP cables have the advantage of being thin, lightweight and flexible. Because of its lighter weight, it is much easier to install, troubleshoot, and expand. It provides versatile and reliable connections, and more importantly, it costs much less than STP cables.



Shielded Twisted Pair (STP) Cable

STP cables have additional shielding material that goes around each pair of wire in the cable, which protects the pair from internal crosstalk, and cancels any external interference along the path where the cable runs along the network. Thus, even when external conditions are far from ideal, you will continue to enjoy maximum bandwidth from your cabling.

The conducting shield that encases the twisted pair of wires in STP cables reduces the potential electromagnetic interference. The efficiency of the shielding depends on the material used, including, other factors such as thickness and frequency, grounding practices, and any shield discontinuity. If the effects of the shield are not properly compensated, it will result to increased crosstalk and signal noise.  

Bulk cat6 STP cables are heavier, thicker, and more difficult to install compared to UTP cat6 bulk cables. Some STP cables use a thin outer foil shield and is often called screened twisted-pair cables or sometimes, foil twisted-pair cables. These are thinner and less expensive than the STP cables that use a thick braided shield. Whether using a braided or the thinner foil shields, the STP is more difficult to install, and you have to consider the maximum pulling tension and minimum bend radius to prevent the shield from being torn.

Another issue that you should resolve when installing STP cables are good grounding and earthing practices due to the shield. When the cable is not properly grounded, it can be a source of interference and emissions. The overall signal quality over the network is also degraded when an STP cable is connected to connectors and outlets that are improperly shielded. For the system to work efficiently in reducing interference, each component must be fully shielded, properly installed, and regularly maintained. Such issues are not encountered with UTP cables, which are inherently easier to install and has fewer potential problems.  


As an alternative to using pure STP or UTP bulk cat6 cable for your installations, you can use UTP for cables that run between the wall and your computers, while the shielded or STP cables provide better performance in areas with high interference and for cables that run inside the walls or outdoors. By mixing the usage of STP and UTP cables, you will save on the cost of cabling and at the same time have less problems with interference from other equipment that cause electromagnetic interference.

To summarize, STP cables are more immune to electromagnetic interference and noise than UTP cables, and are better at maximizing bandwidths. However, STP cables are costlier, heavier, and more difficult to install. For home and small businesses, UTP cables continue to be more prevalent and popular by providing reliable connections at lower cost, while large-scale companies that use more high-end applications that require the maximum bandwidth use STP. STP cables are also used in outdoor environments where additional interference can be encountered from other structures.


For most common uses for home and small offices, installing STP or UTP cables will not spell much difference in the quality of your network. Because it is much cheaper and easier to install, UTP is the more logical choice. Cat6 Ethernet cables are quite expensive so when you are planning to install bulk cat6 STP or UTP cables, you can avoid having excess Ethernet cables by building your own cables to the exact length that you need. 

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