Can You Hook a Wi-Fi Router to a Power-Line Adapter?

A power-line adapter is a system for carrying data through the electrical circuit in a house. To use it, you need to connect your router (wired-only or wireless) to an adapter that plugs into a power outlet. You then need another adapter for each device you want to connect to your router this way. The adapter can plug into any other power outlet that is on the same circuit and connects to the device by an Ethernet cable.

Although several different technical standards exist, many manufacturers use a standard called HomePlug. You need to make sure all the adapters you use run to the same standard or the data may not get through to its destination. The most common variant of HomePlug, known as HomePlug AV, offers connections speeds around four times that of the most common form of Wi-Fi.

In a normal power-line set-up, you must plug each device via Ethernet cable into an adapter in the power outlet. This is fine for desktop computers, but is inconvenient for some mobile devices and unworkable with devices that only work with wireless connections such as most smartphones and tablets. One way around this is to connect your main router to a power-line adapter and then plug a second, wireless router into another power-line adapter -- for example in a room that can't get a wireless signal from your main router. You can then use this second router to relay a wireless Internet connection to your other devices.

The main restriction of using the two-router method is that you will usually need to configure the second router to act as a wireless access point rather than operating in standard wireless router mode. This means the second router simply receives and rebroadcasts data without trying to assign it to specific devices; if you don't configure it this way, the two routers could send out conflicting routing information and cause networking problems. Exactly how you configure this depends on the make and model of router, but the general principles are that both routers must have the same SSID (network name) and encryption settings (including password) and that the second router must have its DHCP feature (which carries out the "routing") switched off; the second router must also have a dedicated local IP address that is outside the range the first router allocates to new devices, thus avoiding any conflicts.

Some models of power-line adapters (often billed as a "Wi-Fi extender) have a built-in Wi-Fi receiver/broadcaster. With these models you do not need to use a second router. Instead you can plug your router into an ordinary power-line adapter in a nearby power outlet, then plug the special power-line adapter into a power outlet in another room. With this set-up, the data passes from your router to the ordinary power-line adapter and then through your electrical wiring system to the special power-line adapter; the data then goes via Wi-Fi from the special power-line adapter to your wireless devices.