Powerline adapters are a pretty cool way to keep your network wired without having to run cables through the walls, particularly handy if you are renting your place (but even if you own the house and you don’t feel like doing this type of work).

Obviously, wiring the house would be the best choice, but when this is not possible, powerline adapters are a very good alternative, and probably still better than just connecting every device via Wi-Fi.

However, the performance of these adapters vary based on a lot of factors, from the distance between the adapters, the quality of your electrical system and, perhaps most importantly, where you decide to plug your adapters into.

Every powerline manufacturer recommends to plug them directly into a wall socket for maximum performance. You should avoid plugging them in anywhere else, including power strips or UPSs. If you do, they will likely still work, but you won’t get the maximum throughput supported.

I used to have a long ethernet cable running from my core switch in the office to the router in the other room, but since getting a dog who apparently loves to eat copper, I had to find an alternative. I removed the chewed ethernet cable and added two powerline adapters into my network, so it was a great opportunity to run some basic performance tests to see how positioning the adapters will affect the network speed. Here are the results.

About my internet connection

My internet connection is, on paper, 50 Mbps down and 20 Mbps up. Ping is normally around 50 ms during a typical speed test. Normally, I get around 45 Mbps down and 18 Mbps up when connected straight to the router, so these will be the values I will compare the results to.

Before running the tests, I ran a speed test when connected straight to the router with an Ethernet cable, and these are results I got:

My connection today is a bit slower than usual, so we will see if we can get 40 Mbps down and 15 Mbps up using the powerline adapters.

About the adapters

For this test, I’m using the TP-Link AV500 Nano starter kit, which I think is a very good entry level set for the price it usually retails at. Since this test focuses on adapter placement, I expect to see similar results even if using other brands or models.

Test #1: Both adapters plugged into power strips

This is the first test I run because it was the most convenient setup for me. All of the power sockets are already used, so I plugged both adapters into power strips. These are the results:

As you can see, I lose almost half of my speed when both adapters are connected to power strips. The connection still works, but the performance is pretty bad.

Test #2: Only one adapter plugged into a power strip

In this test, I left the adapter connected to the router plugged into a power strip, but I moved the adapter connected to my core switch and plugged it straight into a wall socket. Results:

So this already gives a pretty good result. Out of curiosity, I decided to run the opposite test too, to see if plugging the source powerline or the receiving powerline straight to the wall socket made any difference.

For this test, I plugged the powerline connected to the router straight into a wall socket, and the powerline connected to my switch back into the power strip:

Basically, almost no difference here.

Test #3: Both adapters connected straight into a wall socket

For this last test, I removed all power strips from the equation, and I plugged both powerline adapters straight into a wall socket. These are the results:

As you can see, this configuration is the closest to the performance I get when plugged in straight into the router.

Conclusions

I ran 4 different tests:

  • Connected straight to the router via Ethernet
  • Connected using both powerline adapters plugged into power strips
  • Connected using one powerline adapter plugged into a power strip and one adapter plugged directly into the wall socket (and viceversa, switching the adapters)
  • Connected using both powerline adapters plugged into wall sockets

The best performance comes from plugging directly into the router, of course, but plugging both powerline adapters into wall sockets was a close second.

Connecting only one of the two adapters to a wall socket had a minimal impact on performance, so it’s still a viable solution if all your wall plugs are used already.

Finally, plugging both adapters into power strips certainly works, but the performance is awful. In my tests, I lost roughly 50% of my internet speed.

Basically, do not use powerline adapters with power strips.