Mistral- are you in the UK or Aus?

I agree- it may thus be faulty!

What are the LEDs doing during this time? You should be able to run the TPLINK Management utility on a PC connected directly to each unit and you should be able to see the other unit in the Network...

Firmware upgrade required?

I doubt the units are causing your breaker to flip as I think you are getting power surges which are causing your units to fail which in turn causes the breaker to trip. Get a surge protector and...

Change the SSID of the WiFi to say " Argentina" and see how that goes. I'm guessing there may be a problem with the SSID having non-standard characters? Another test is to drop the security on the...