The mouths are made of metal, pipes are made of PVC, there is no grounding and the problem is that it is all in a single circuit, sockets and lights. I will see if I can interrupt rooms, although I will have to disarm the whole house practically
That is the problem, the job of finding a loss is really complicated, especially if you do not have inspection boxes where you can interrupt the circuit, but it is the only way.
Start by checking the boxes of the light keys and outlet, usually where these problems occur.
The problem is in my room from what I saw, disassemble the ampalmes and leave all the sockets and light disconnected and look at the meter and did not turn, I have connected to an outlet an alarm sensor in the window, those of opening, remove it and it seemed that the loss stopped, I connected it again and the loss returned, then disconnected it again to make sure and the meter kept turning. I will keep looking but I think I will choose later to make the new installation, it is already very old.