How to Buy Ethernet Cables: what to look for

It is important to select the right Ethernet cable to ensure the best performance is obtained for the best price: Cat 5, Cat 5e, Cat 6, Cat 6a, Cat 7 what is the best buy?

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Buying Ethernet cable is not always as easy as it might seem. There is a huge selection of network cables of different types; Cat 5, Cat5e, Cat 6, Cat 6e and Cat 7, as well as different lengths colours and the like. These are available from a variety of different suppliers.

It is important to buy the right network cable: over-specify it and you will pay too much; under-specify it and the performance will be impaired and the local area network or Ethernet link will not work as well as it might.

Ethernet RJ45 connector on an Ethernet cable
Ethernet RJ45 connector on an Ethernet cable

Selecting the right Ethernet cable will ensure the best performance is achieved for the best possible price.

To ensure the best network cables are bought for the system, it is necessary to have a little understanding of what is needed. It is worth taking a little time to assess exactly what is needed and find out the various options of what Ethernet cables are available.

Aspects like performance, price, availability, quality and more all affect the decision. Although some are difficult to judge, knowing the facts can help make an informed decision about the best Ethernet cable to buy.

Ethernet cable requirements

Local area networks are commonplace these days. Homes with broadband have routers that not only give Wi-Fi, but also have the option of Ethernet connections as well.

Typical routers for the small office or home local area networks often have four Ethernet ports, and those for larger offices will typically be dedicated Ethernet routers and Wi-Fi access points that are be able to be located as required.

The routers and additional switches that can be installed in many local area networks mean that many more Ethernet cables are needed.

Although Wi-Fi is advancing and offering much higher levels of performance, so too is Ethernet, and the associated network cables offer some distinct advantages in many circumstances.

Wi-Fi can be dependent upon the location; whether there are any obstacles on the way, the distance to the router and much more. Ethernet cables offer a reliable level of performance and are often preferred for many offices, and they can be very useful for home local area networks as well.

When thinking about the cable to use, remember that for many connections, it is the Internet connection that is the slowest link. Even fibre broadband will be slower than the average Ethernet cables, so if it is just for Internet surfing only, then a very average Ethernet cable will suffice.

When the better Ethernet cables come into their own are when files are transferred between devices for backing up, streaming video, streaming games, and the like. The faster speeds of the more up to date better Ethernet cables can make a real difference.

Often the issues can arise when older network cables are used. Most of us will have an accumulation of Ethernet cables that have been acquired over the years. These may be from earlier standards and may affect performance. If the cable has come with a new Ethernet router, then it is probably one of the newer categories that will be fast.

Ethernet cable performance

There are a number of Ethernet cable categories that can be seen advertised. Cat 5, Cat 6, Cat 7 are all widely available, with Cat 5 being the oldest standard and Cat 7 the newest network cable category and with the highest performance.

Read more about . . . . Ethernet cable categories.

The different category cables have different levels of performance and as a result it is important to select a cable that will meet the requirements for the system

Using the table below it is easy to see the comparison between the levels of cable performance for when they are bought.

Ethernet Cable Performance Summary
Category Shielding Max Transmission Speed (at 100 meters) Max Bandwidth
Cat 5 Unshielded 10/100 Mbps 100 MHz
Cat 5e Unshielded 1000 Mbps / 1 Gbps 100 MHz
Cat 6 Shielded or Unshielded 1000 Mbps / 1 Gbps >250 MHz
Cat 6a Shielded 10000 Mbps / 10 Gbps 500 MHz
Cat 7 Shielded 10000 Mbps / 10 Gbps 600 MHz
Cat 8 Shielded 25 Gbps or 40Gbps* 2000 MHz

* 25 Gbps for Cat 8.1 and 40 Gbps for Cat 8.2.


One of the good things about the Ethernet cables is that they are interchangeable and they are also backwards compatible. The only real issue with using an older type cable like the Cat 5 is that it won’t support such fast data transfer speeds.

It is possible to plug a Cat 5 cable into a router that has the latest 10G Ethernet interface. The only issue is that the cable will slow the data transfer down. This may or may not be a problem dependent upon the type of file transfers.

Similarly it is possible to plug a Cat 7 cable into an old router that does not support the latest speeds. and it will all work fine.

This means that when buying an Ethernet cable, there is a lot of flexibility - the worst is that the network cable might slow things down a bit.

Ethernet cable length

Ethernet cables come in a variety of standard lengths. Whilst it is possible to construct your own cables, most people will want to use one of the pre-made cables.

Cables are widely available in a variety of lengths: 0.5, 1, 1.5, 2, 5, 10, 20 metres are very common and these cables can be obtained from virtually any supplier that stocks Ethernet accessories.

Long Ethernet cables are also widely available, and maximum lengths of around 75 metres are relatively easy to find, although they will naturally be more expensive than the shorter lengths.

If different lengths are needed, shop around because there is a huge selection available and different stockists will stock different cable lengths, some with a much greater selection than others.

When determining the length for a particular cable run, make sure the cable will be long enough. Typically there needs to be a little slack because cables always seem to need to be longer than the very shortest lengths measured.

Allow a little margin, but not so much that there is a lot of cable length to be used up. Long Ethernet cables can be great, but over do it and they can be a bit too much of a good thing! That said any extra length can be neatly looped together and secured with a cable tie.

Obviously when installing cable into a house along with other permanent wiring, cable in a reel will be bought and terminated as required to the relevant sockets. Reels of Ethernet cable can be bought in reels up to 500 metres or more.


Cable ideas

Ethernet cable are available in a huge number of lengths, 3 feet / 1 metre,   5 feet / 1.5 metre,   are common lengths, but very many more are available.

Check out this link for more Ethernet cables.



Cable colour

Whilst for many applications, the cable colour is not important, in some instances it can be very useful to be able to select the colour.

When there are many cables together it can be helpful to have a variety of different colours and this helps track the cables through and make sure the right cable is connected to the right position.

Having different colours to identify different cables can be very useful where a large router or switch has many connections, or there is a patch panel of some description. Also where there a long Ethernet cables, possibly running with others it can help in identifying the cables.

In some instances an Ethernet cable colour code may be devised for cables with different uses, or those connected to different branches of the local area network. Cable colours can be put to good use like this.

For domestic use on home local area networks, the complexity is much less and colour coding of wires is not normally an issue. Here the colour choice may be required to make it stand out less - grey may be a good choice as it is quite neutral, although there are many more colours to brighten things up.


There are many different suppliers of Ethernet cables. Some may be specialist suppliers and others like Amazon stock a huge number of other items as well.

For commercial installations, there is normally a requirement to go to a supplier with whom there is an account so that items can be bought and the number of different suppliers a company has is minimised.However for many applications it is possible to go to a variety of different suppliers. Amazon is easy and delivery is normally very swift. If quality is an issue, then a reputable make can be chosen from the enormous list of available items.

In other instances a specialist IT or cable supplier may be chosen. It is always a balance between performance (including reliability), availability and cost. That said the quality of most cables is very good and the performance is dependent upon the selection of the Category type.

Ethernet cable choices summary

The big decision when buying Ethernet cables is making the choice of the best cable. Performance benefit over cost.

Markings on a Cat 5e Ethernet cable
Markings on a Cat 5e Ethernet cable

For domestic use Cat 5e cable is currently generally adequate for most applications, although in years to come they may start to limit speeds as they increase further. The Internet connection is normally the main bottle neck and if you are not continually transferring huge files, then using Cat 6 or Cat 7 cable is not likely to make much of a difference. In any case all the Ethernet equipment has to support the higher speeds anyway and any transfer will default to the lowest speed element in any connection.

If you want to be sure of getting the best speeds, then Cat 6 and Cat 6a cables are a good bet. They often don’t cost too much more than Cat 5, and for future-proofing then they are a wise option. Also Cat 5 is now obsolete so it is best not to use it.

Cat 7 cables don’t offer a huge advantage over Cat 6a in real terms at the moment. That said they do offer better shielding and this can help maintain speeds where long Ethernet cables are needed. So for cables that are being installed, say, to wire a home, then it can often best to pay the extra to ensure the best speeds and this will future-proof the system for as long as possible.

Check out the Electronics Notes: Essential Ethernet Equipment List.

For commercial systems, it is obviously worth paying the extra for the fastest cables possible. Small savings at the expense of performance can cost money over the longer term.

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