I'm in Australia, using the Australian versions of the TL-PA9020P kit, in case that's relevant.

I have two power circuits in my house (separate circuit breakers – I'm not certain if they're connected to separate phases of the three phase power).

The first (let's call it A) has the power outlets from the front of our house and hence most of the network devices. The internet router is on this circuit. I've got my office, the router and the media center all on this circuit, connected using a set of TL-PA9020P units and it all works fine, I get decent speeds.

The second circuit (let's call it B) has the power outlets from the back of our house and my partner's studio in the backyard. What I want to do is to extend internet access to the power outlet in that studio.

I've setup one TL-PA9020P inside the house and another in the studio and verified that they connect.

In my initial attempt to make this work, I just ran an ethernet cable from a TL-PA9020P on circuit A to a TL-PA9020P on circuit B. It's just like extending a LAN with a hub after all, right?

No. As soon as I connect that cable, the rest of the powerline network goes screwy, the other computers can't seem to find each other or the internet. If I unplug the cable, everything is fine.

So I came here and I found the FAQ in this forum and this diagram:

… and so I bought a $20 desktop network switch and put it between the two TL-PA9020Ps, so there's a switch between circuit A and circuit B.

… Same result. As soon as I make the connection, everything goes crazy.

Can anyone help me figure out why this is going so wrong or give me some advice on how to make it work?

Thanks in advance for any time and help you can offer,

Tim