Thank you Gentlemen. My initial post was a bit premature … I should have read a bit more before posting … :(.
In any event, I think I have the answers to all my questions now and, while the Sonoff R2 POW has good features, it is not suitable to install in simple plugs/contraptions … while being consistent of the building code where I live. Yes, this is a hobby, but at the same time one does not want to mess with ‘exposed’ wiring as (from personal experience) the home insurance company won’t like it too much.
I’ll continue my search for power monitoring, and post findings if/when I find something ‘suitable’.
It is not as bad as you think.
If you got a wired lamp, just cut the wire, and connect the two loose ends to the Pow R2 in and out. Thats basicly all you have to do. (remember to unplug the lamp first ofcouse ).
You can also connect two pices of wires to the Pow R2, and wire a plug (femaleat one end, and a male at the other). Then you just add it to your exsting wired lamp. Like an self made extension cord, with the Pow R2 inbetween.
It really is that simple.
Another option is to get a plug socket like these with power monitoring:
But if you need it behind your wall box, then its probably way too big ofcouse. There are suitable devices for this purpose. But I´m not sure if they´ll run WiFi.
I did post that link as an example of using a smartplug insted of a Sonoff POW R2 to measure the energy (power). I could have mentioned any smartplug devices, this was just an example for showing options for measuring the energy