How To Pick The Right Data/ Network Cable

If you planning on an installation that requires data cabling, like a computer IT network or a HD video TV system. At some point I’m sure you will ask yourself, what data cable should I buy? Which cable do I need or what is the best quality Ethernet cable. In this article, I discuss many of the makes and types of data cables, an explanation of the terminology and what to look for so that you can make your own informed decision what is best for you.

Best Data Cable

If you’re looking for the best data cable you can find. It’s important to note that “best” is a relative term. Data cables have a wide range of applications including but not limited to, Ethernet/ networks, telephone and voice systems, HD Video systems, CCTV, POE and more. Sure, you could install Cat8 everywhere in your property which would be capable of providing a super-fast connection throughout but more often than not, especially with domestic home AV and communications systems this is completely unnecessary and overkill. It will cost considerably more than is necessary, make your installation more difficult and may not actually benefit you in any way. I frequently get asked to install Cat7/ Cat 8 cables for a single 15m run that will only connect to a Smart TV or something similar, which is completely unnecessary. For your reference as it will be mentioned many times within this blog, ‘Cat’ stands for category.

Data/ Ethernet Cable Categories

There are numerous standards and categories for network cables. The higher the amount of traffic or the faster the internet speed the higher specification cables will be required to support this. All Ethernet cabling standards are backwards compatible with previous standards. An example of this is Cat6 can support 10Gbps Ethernet and also a previous connection speeds like 1Gbps, whereas lower standards like Cat5e can support 1Gbps but not the higher standard 10Gbps.

Cat5

It’s common within the trade to refer to a four twisted pair cable as just “Cat 5”, whereas the installer may actually be installing Cat5e, Cat6 or similar. Category 5 cable has been superseded with Cat 5e cable and there would not be much point in installing it nowadays. Cat 5 was typically used for 10 or 100Mbps networks.

Frequency – 100Mhz (350Mhz max)

Max Data Rate – 1000Mbps

Networks Supported – 100BASE-T + previous standards

Cable Construction – UTP or STP

Cat5e

Cat5e stands for Category 5 enhanced. This has all but completely replaced Cat 5 cables now. Cat 5e cable is very similar to standard Cat 5 cable but was introduced to meet new specification requirements. It includes improvements on attenuation losses, Return Loss (RL) and Cross Talk. Cat 5e is typically used for 100 or 1000Mbps networks.

 Frequency – 100Mhz (350Mhz max)

Max Data Rate – 1000Mbps

Networks Supported – 1000BASE-T + previous standards

Cable Construction – UTP or STP

Cat6

Cat6/ category 6 cable is a further improvement on the Cat5estandard. It is slightly thicker and incorporates a plastic insert called a Star Filler (sometimes referred to as cross-filler, spline, cross-web filler, separator)around which the for internal pairs twist around. Cat6 is typically utilisedfor 1Gbps (1000Mbps) Ethernet networks, usually referred to as “gigabit”, but can also support 10Gbps up to 100m.

 Frequency – 250Mhz (550Mhz max)

Max Data Rate – 10,000Mbps (up to 55m), 1000Mbps (100m)

Networks Supported – 1000BASE-T

Cable Construction – UTP or STP

Cat6A

Cat6A stands for Category 6 Augmented. Cat6A was introduced with the desire to support 10Gbps networks over 100m. Although standard Cat6 can carry 10 gigabit Ethernet up to 55m, this isn’t always suitable for larger computer networks where longer cable lengths may be required. The Cat6 standard specifies cable operating at a minimum frequency of 500Mhz.

Frequency – 500Mhz (up to 550Mhz)

Max Data Rate – 10,000Mbps (100m)

Networks Supported – 10GBASE + previous standards

Cable Construction – UTP or STP

Cat7

Cat 7 stands for Category 7. This specifies a frequency range up to 600Mhz over 100m. Unlike previous standard such as Cat5, Cat 6 etc, where you have the option to purchase a screened (UTP) or screened cable (FTP/STP), Category 7 cable is a fully screened cable. This screening means that Category7 cable virtually eliminates all Crosstalk between pairs and offers very good protection against EMI/ RFI.

Frequency – 600Mhz

Max Data Rate – 10Gbps

Networks Supported – 10GBASE-T + previous standards

Cable Construction – STP only

Cat 8

I’m sure you’re getting it by now, but Cat8 standards for Category 8 and at the time of writing this is the current latest standard. Any further improvements or requirements would probably necessitate fibre optic cabling instead. Cat8 differs vastly on previous standards. It can carry 2Ghz(2000Mhz) and connection speeds of 25Gbps/ 40Gbps over 30m. Cat8 cable is still not widely available on the market and is expensive when compared with previous standards. Cat8 is also a fully screened cable only and does not available in shielded twisted pair

Frequency – 2Ghz

Max Data Rate – 25/ 40Gbps

Networks supported – 25GBASE-T, 40GBASE-T + previous standards

Cable Construction – STP only

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Data Cables Screening Explanation

The are numerous types of screening that are used within data cables. Some will have an external screen surrounding all internal pairs, others will have a screen around the individual pairs, some will have both and others none at all. In this section we name all the different variations that are available. The better cables will incorporate some form of screen as it's the quality of the screen which helps achieve the higher standards and faster speeds.

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U/UTP

The most common type of network cable that is installed is Unshielded Twisted Pair, commonly abbreviated to UTP. Unshielded cable doesn’t have any foil/ metallic screen outside running inside the cable between the twisted pairs and the outside sheath. The purpose of the screen is the protect against external interference such as RFI, EMI and impulse noise. Unlike other cables like coax cables, the twisted of the pairs itself helps minimize interference pick but even it’s particularly important to try to not install UTP cable immediately beside or running parallel with mains electrical cables.

F/UTP

Commonly referred to as ‘FTP’, this type of data cable has a foil screen between the cable sheath and the unshielded twisted pairs. The foil screen helps offer further protection from electro-magnetic and radio frequency interference. This cable also comes with a drain wire which helps ground unwanted interference. Shielded RJ45 terminations should be used with this cable.

S/UTP

This cable is similar to the above F/UTP in the sense that it has four unshielded twisted pairs, but rather than a foil screen it has a braid screen similar to that in coax cables like RG59. This type of cable is most commonly referred to as ‘STP’ cable.

SF/UTP

This cable has four unshielded twisted pairs, surrounding by a foil screen (F) which is then surrounded by a braid shield(S) much like a double-screened coaxial cable. The two screens together offer greater protection from EMI/ RFI/ Impulse Noise compared with other single screened versions and also offer improved grounding due to the braid.

U/FTP

This type of cable has no shielding that surrounds all the four pairs (that’s what the ‘U’ stands for), but rather has a separate foil screen surrounding each individual pair. This too will help protect against unwanted interference and electrical noise pick up and offers further protection against cross-talk between the other pairs inside the cable.

F/FTP

F/FTP cable has both an individual foil screen surrounding each individual pair offering protection against cross-talk between adjacent pairs and a further external screen surrounding all of the pairs together. This offers superior protection against RFI, Impulse noise and EMI.

S/FTP

I’m sure you’re getting it by now, but S/FTP cable has four individual foil screens surrounding each of the twisted pairs to protect/ minimize against interference and cross-talk, and further braid shield that surrounds all four pairs which offers better grounding protection.

SF/FTP

Last, but no by no means least when it comes to protection from the various sources of electrical interference as this cable type offers the best protection. SF/ FTP cable has four individual foil screens surrounding the individual four pairs, surrounding by another foil screen that surrounds all the pairs, surrounded by a further braid screen.

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Pre-terminated Ethernet Cables

A pre-terminated Ethernet cable already has the connecting RJ45 or 8P8C plugs fitted to the cable, meaning no specialist termination tools or fitting is required. Pre-terminated Ethernet Cables are often referred to as patch leads or fly-leads. These can be purchased in a variety of lengths, colours, with or without screening and to various category standards, Cat5e, Cat6 etc. The problem with purchasing these cables are they are not very installation friendly. If you need to route them wall a wall for example you will need to drill a hole larger enough to fit the connector through and not just the cable. You are also restricted by the length that you buy, meaning they are not cut to length, if you purchase a cable too short it won’t reach it’s desired location, too long and you will have excess that you will need to hide.

Fully Wired Ethernet Cables vs 2 Pair Ethernet Cables

A fully wired Ethernet cable has a total of four pairs with8 terminated contacts. This is referred to as 8P8C (8 position, 8 contact),these can be seen if you look at the end of the connector. Some Ethernet cables only have two pairs connected, these are usually terminated into pins 1,2,3 and 6. It’s important to note the distinction because if you’re trying to run 1Gbps Ethernet or higher, the 2 pair Ethernet cable will limit you to 100Mbps.

Stranded vs Solid Cable

The difference between stranded and un-stranded network cables, is referring to the centre conductors in each of the individual pairs. A stranded conductor is lots of small individual strands which together make up the diameter of the conductor and solid (un-stranded) cable is one continuous solid conductor. Un-stranded cable is more flexible making it personally more suitable for situations where the cable is likely to be moved around a lot and solid cable is more durable making it more suitable for longer cable lengths and permanent installations. I personally would never purchase a stranded cable.

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Copper Conductor vs Copper Clad Steel/ Aluminium Conductors

The best data cables utilise a solid copper conductors on each of the internal cables. Cheaper cables may utilise Copper Clad Steel (CCS)or Copper Clad Aluminium (CCA) instead. The clad refers to a thin outer copper coating over the steel or aluminium conductor. The main reason for purchasing CCA or CCS cables would be to reduce the copper content of the cable, which will reduce the cost.

LSZH Data Cable

LSZH stands for Low Smoke Zero Halogen. The difference between these and PVC cables is that in the event of a fire and the cable gets burned, the LSZH reduces the amount of dangerous and poisonous gases. LSZH it increasingly being used for internal data networks, LANs and structured cabling systems.

Crossover Cable

Typically only used for hub to hub connections or connections between network switches. A cross over cable has different terminations on each end. This allows for separate transit and receive pins to be utilised. There are various types of crossover cables. On some only the green and orange pairs are reversed, on others all the pins are. When purchasing pre-terminated cross-over cables, it’s important that you purchase the correct cable for your requirements. When using standard data cabling for a cross-over connection, it’s just a case of terminating the cables within the desired pins.

UV Stable External Cable

If you need to install data cables on the exterior of a property, or anywhere where they might be exposed to direct sunlight and weathering. You must use an appropriate external network cable for this, usually labelled or advertised as ‘UV Stable”, standard indoor cable is not suitable for the task as the outer sheath can quickly break up and become brittle potentially exposing the inter conductor pairs to external weathering and rainwater. External cable shouldn’t be used internally and cable lengths at entry points should be kept to a minimum.

Direct Burial Data Cables

Direct Burial cables as the name suggests are suitable for burying straight in the ground. These cables usually have some sort of jelly or grease to protect against any moisture penetrating into the core of the cable and the outer sheath is UV resistant to prevent in corroding in sunlight overtime. Personally, I prefer to at least route the cable with a conduit or flexi-conduit to protect it in any case.

Armoured Data Cable

Like electrical cables, there are armoured Data/ Network cables available on the market. The purpose of an armoured cable is to offer protection against physical damage, making it perfect for underground ducting, direct burial and mechanical environments. What makes the cable armoured, is underneath the cable sheath, there is a wire armour (usually a galvanised steel) protecting the inner pairs. Armoured cable is not as flexible as non-armoured cable and more difficult to work with.

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Ethernet/ Network & Data Cable Questions

I hoped that you enjoyed this article, if you have any comments or questions please feel free to post them within the Blog Comments section below and I will endeavour to answer these personally. Please be patient when posting your comments as I may not be able to answer as fast as you like. A few groundrules first however.

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Until next time,

Tom.