I entered into a 32-years-old apartment. I checked all sockets with a super-tester. All of them are OK, except two sockets in a single room, where the super-tester shows "no grounding".
I talked with an electrician and he said that it might be related to the "control box" of the room, which is hidden somewhere behind one of the wall. EDIT: This is NOT the fuse-box of the entire apartment, which is visible just outside the door of the apartment. It is a control box for this specific room - a box that collects the wires from the general fuse-box and distributes them to the electricity points inside the room (two sockets and one light-bulb).
To detect this mysterious "control box", I used a radiation-tester. The radiation-tester shows electric radiation of several hundreds V/m near the socket, but, it shows no radiation in a circle of radius 1 meter around the socket, so I do not know how to find the control box.
My questions are:
- How can I find the control box of the room?
- Is this control box really the reason for the lack of grounding in the room? Or is there a different solution?