I'm about to drill some 5mm diameter x 35mm deep holes to support a new curtain rail and when I used a voltage/metal detector to check for cables etc. it gives an alert for the entire surface of the wall. Is this possible and does it mean there may be a problem with the electrics in the flat?
Possible things I have thought of are:
The detector isn't calibrated correctly. I have calibrated according to the instructions The wall paint is conductive.
What should I do?