For the latest Powerline buying advice and recommendations read our newer articles: What is Powerline - buying advice, tips and speed myths and Best Powerline adapters group test.

Powerline networking adaptors aren’t all that well known, but are enormously useful. Instead of stretching Ethernet cables from room to room, Powerline technology allows you to create a network using the existing mains electrical wiring in your home or office.

This means you can extend the network to any room that has a spare power socket. This is especially useful for remote rooms where a Wi-Fi signal might not be able to reach.

See also Group test: What's the best powerline adapter?

It’s a great option – not just for computers, but also for devices such as games consoles or TV set-top boxes that require a wired network connection but may be some distance away from your router (or in a different room entirely).

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How many adaptors do I need?

You need one adaptor for your router and one for each additional device that you want to connect to your network. You can buy adaptors individually, but we’ve rounded up starter kits from a number of manufacturers that include two adaptors as that’s the minimum you need to connect a single computer or other device to your network.

Compatibility betweeen standards

In order to ensure compatibility between products from different manufacturers, most products have adopted a standard networking protocol called HomePlug. In fact, the terms ‘powerline’ and ‘HomePlug’ are often used as though they’re interchangeable, but there are competing standards. HomePlug is the most popular, though.

Kits that support the HomePlug standard may run at different speeds – most of the kits reviewed here adopt the HomePlug AV standard which nominally operates at 200 megabits per second (Mbps), which is fine for web browsing and most streaming video.

However, if multiple computers need to play high-speed online games and stream high-def video at the same time you might want to consider slightly more expensive kits that run at 500Mbps (also known as HomePlug AV2). There are also ‘gigabit’ kits starting to come out, which run at 1000Mbps, although these are still relatively rare and quite expensive.

You can mix and match Powerline adaptors running at different speeds and from different manufacturers – as long as they all support at least HomePlug AV. Naturally, faster adaptors can talk to slower ones only at the lower speed.

Beware of older kits still on sale that are based on an earlier standard called HomePlug 1.0. These run at a maximum speed of 85Mbps – which will probably still be adequate for many home users – but they’re not compatible with faster HomePlug AV products running at 200Mbps or more. They'll co-exist on the same mains wiring, but cannot talk to each other. Most home users should probably stick with newer HomePlug AV products in order to keep things simple.

Other features

As well as providing a simple plug-and-play network connection, there are other features that you might want to look out for too. Most Powerline adaptors only include a single Ethernet port, but you can buy adpators with three or four Ethernet ports, which makes them great for connecting multiple devices to one mains outlet.

If there are rooms in your home that can’t receive a good Wi-Fi signal, look for a kit with a ‘Wi-Fi extender’ option. You plug one of the adaptors into a mains socket in the room in order to create a wired connection to your main router, and then use the adaptor’s wireless features to set up a mini Wi-Fi network as well. Such adaptors also have one or more Ethernet ports.

Finally, some adaptors have a mains passthrough socket, which effectively gives you back the mains socket the adaptor would otherwise be occupying.

HomePlug with Wi-Fi

What are HomePlug's limitataions

There are a few things to bear in mind if you want to get best performance from your powerline network.

  • The distance between sockets shouldn’t be a problem in most homes and office, but the age of the electrical wiring may affect performance in some older buildings.
  • You shouldn’t plug a powerline adaptor into a multi-way extension either – they really need to be plugged directly into a mains socket in your wall. You can try your adaptors in a multi-way extension but don't be surprised if they can't connect to each other or have much reduced transfer speeds.
  • Talking of transfer speeds, you may also find that some electrical devices, such as mobile phone chargers, can cause interference if they’re plugged in somewhere in your home on the same ring main.
  • You can enable encryption in adaptors, but they will only talk to other adaptors on the same mains network (usually wiring that's attached to one electricity meter). This means your neighbours in a block of flats, for example, won't be able to access your network if they install some adaptors too.

For the most part, though, powerline networking really is enormously straightforward. It’s simpler than setting up an Ethernet network, and can reach further than a Wi-Fi network. That makes it ideal for both home and business users who want to connect multiple rooms to their network with the minimum of fuss.