A friend has a guesthouse located 20 feet from the main house. I would like to install a 'powerline' device bridge in the guesthouse for wifi.

Is there a simple test that can be performed, before purchasing the Powerline device, to confirm that the endpoints will work with the powerline device?

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    You can determine this by the circuit breaker, however, unless the guesthouse is on the same circuit as something on the main house PowerLine isn't going to be useable. – Ramhound Dec 6 '18 at 17:30

Go to your house circuit breaker and switch off the master circuit breaker.

If both the guest house and main house power circuits go off then chances are the powerline network device will work.

They work best on the same ring mains, but so long as you are on the same supply from the street then chances are you should be fine. Some consumer boxes (circuit breaker groups) have filtering between breakers which can interfere with powerline devices on different rings though. YMMV.

If the guest house and main house are on separate electricity supplies then it may not work well, if at all.

  • "switch off the master circuit breaker" -- Not a good test. Ideally the endpoint should be on the same branch circuit. Then on the same phase. – sawdust Dec 6 '18 at 18:25
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    @sawdust - I think Mokubai's train of thought is that, if the guest house is on the circuit is on the same breaker as the main, turning off the master switch is a fast and dirty test. Of course, it's horrible for electronics. – Ramhound Dec 6 '18 at 22:10

After turning off all electronica in main and guest houses, go to your house circuit breaker and switch off the master circuit breaker.

If both the guest house and main house power circuits go dark then you can test further.

Then, if you have an electrically-saavy friend with a Fox and Hounds circuit tracer, invite them over for a beer or six. Before the beer is opened, they can inject an audio tone (with the 'Fox' part of the set) on the circuit leg from the PC, and if the 'Hound' (amplified speaker) can hear it in the guest house, then it may, repeat may, work. If it cannot be heard, it won't work.

Why the uncertainty? Because power line networking requires being on the same phase leg of the same circuit, and with a Fox and Hounds set, you don't know if you're on the same phase leg.


I strongly advice against the use of this powerline adapter. I tried to use the exact same model in my old house just to improve the wifi on the second floor and the speed was only 20Mb/s at best. The devices were in the same phase, 15 feet apart.

The poor performance wasn't the only problem, the devices disconnected from each other randomly and the quickest way to make them connect again was to pull one off the socket and insert it again.

I don't know about other powerline adapters, but I bet you will have way less trouble if you try to run an ethernet cable to connect both houses.

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    Definitely considering the ethernet option if owner is agreeable – gatorback Dec 7 '18 at 3:18

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