What is powerline networking?

In this guide

There’s no doubt Wi-Fi is a wonder of the modern age, making it effortless to connect devices across your home without the need for wires. But sometimes Wi-Fi isn’t the answer and there are occasions when you need to complement your wireless with other solutions.

For times when Wi-Fi doesn't have the reach we've got powerline networking, an affordable and easy way to use wired networks.

What is a powerline network adapter?

Powerline network adapters, aka HomePlugs, are devices which transmit data over electrical wires, transforming an electrical circuit into a data network. This allows you to create a wired network with minimum effort, and without the need for miles of cabling snaking throughout your home or office.

To get started with powerline networking you simply need two powerline adapters and some network cables (which are usually supplied).

One adapter is plugged in next to the home broadband router and linked with a network cable. The other adapter can go anywhere on the same electrical circuit, which for most of us will be anywhere in our home. The other end could provide wired connectivity to a device (such as a computer or games console) in another room, or extend a wireless network using a powerline Wi-Fi booster.

Powerline adapters usually connect automatically and do not require drivers. Once you’ve got that second adapter powered up you can bring internet connectivity and networking to any devices on the other end right away.

What kind of HomePlug adapter should I buy?

There’s a huge variety of powerline gear with many added extras to suit most requirements, so what should you be looking for?


The key differentiator to consider when choosing a powerline adapter is speed.

Early HomePlug models were only capable of a puny 14Mb transfer rate, but today's entry level models offer 200Mb or 500Mb, and the latest hardware boasts of speeds up to and over 1200Mb.

However you should take advertised speeds with a huge pinch of salt.

A 1200Mb adapter will in reality provide a performance of 100-120Mb at best, while the 500Mb models deliver about 60Mb, and 200Mb adapters are typically capable of around 30-40Mb.

(Remember: Mb or Mbps is a measure of speed in Megabits Per Second, not to be confused with megabytes or MB, which is the size of a file. At a transfer rate of 100Mb it would take eight seconds to move 100MB of information).

Consider how this will impact your usage. If you’re just using powerline adapters for web browsing and other low-bandwidth tasks then a 200Mb adapter will easily suffice. But if you’re planning on streaming high definition video or moving large files regularly then it’s worth opting for the higher speed adapters.

Take your broadband speed into account too, otherwise you could find the performance really drops off when using the powerline. Anyone with a fibre or cable connection will want to get a powerline device capable of 500Mb or faster. If you’ve got a very quick connection like Virgin Media’s 300Mb cable you should use the fastest powerline adapters available to avoid limiting the broadband performance.

Finally, it’s very important that you account for the network interface on the devices you’re connecting to the powerline setup. For a long time the standard speed of a wired network connection was 100Mb, and lots of computers and other hardware will be limited to that rate. But if you’ve purchased a computer or other device with a network port in the last few years it likely supports faster "gigabit ethernet".

If you’re planning on using powerline networking for speeds above 100Mb you’ll need to make sure that your router and ports all support gigabit, otherwise it will be limited to the slowest link in the chain. And if you’re building a new network from scratch it’s a good idea to use Cat 6 ethernet cable for the fastest speeds now and in the future.

Ports and passthroughs

A basic HomePlug will have a single ethernet port, but some models offer several network connections so you can connect multiple devices.

The multiport adapters are usually only a little more expensive and worth it even if you don’t need those ports right away. Otherwise to add more ports later on you’ll either need to replace the adapter or use a network switch (which aren’t expensive, but it’s additional clutter)

Some adapters will also have passthroughs for the socket so you don’t lose access to it. Not essential, but a useful thing to have if power points are at a premium.

Wireless extenders

Some powerline adapters also act as Wi-Fi boosters. This is a really great way to bring wireless connectivity to areas of your home where the signal is weak or nonexistent.

Compared to Wi-Fi repeaters which amplify a weak signal the connection should be faster and more stable, though you will still lose some performance. Also be prepared to pay a bit more for this capability.

Frequently Asked Questions about powerline adapters

Can I use a powerline adapter on an extension socket?

Powerline adapters may work with an extension lead or power strip but it can have an impact on speed and reliability. Surge protected extensions in particular may result in a very noticeable difference to performance, and might not work at all.

It can’t hurt to try so experiment with both. If you’re not transferring lots of big files, streaming HD movies or trying to get the maximum broadband speed at the other end then it might not matter, otherwise they should go straight into the wall for the best performance.

Why is my powerline connection so slow?

Distance from your router, other electrical items and the quality of your power lines can all have an impact.

If performance is poor you should try other sockets and run a speed test at each point to find the best position.

Some adapters have indicator lights which give a rough idea of the speed.

Also keep in mind what we said above about the speed of powerline adapters. They may be advertised as 500Mb but that’s wishful thinking. In practice the speed is going to be far slower.

Are powerline adapters backward compatible, and can I mix adapters from different manufacturers?

If you're buying a new powerline setup from scratch you are best off getting the same make and model to ensure compatibility. However, leaving aside the reduced performance when connecting to a slower adapter, mixing powerline kit of different speeds from different manufacturers isn't usually an issue so long as they support the same standards.

The most popular type of home powerline gear is HomePlug. In the same way as Wi-Fi networking has been standardised, the HomePlug Alliance has created specifications for manufacturers to follow to ensure a dependable level of performance and compatibility.

HomePlug 1.0 was the original specification but has since been supplanted by HomePlug AV and HomePlug AV2.

Any adapter meeting a HomePlug AV standard should be compatible with another. But older HomePlug 1.0 devices will not usually work with AV (though they should be able to coexist).

There are other types of powerline standards, notably the competing HomeGrid (aka G.Hn). These devices will not work with HomePlug adapters, but since they’re not widely available in the UK you’re unlikely to encounter this problem.