I have a loud electrical sounding humming noise that is vibrating through my house, and appears to be coming through the adjoining wall of my neighbour's house. It starts and stops at any time of day or night, even with my electricity / heating / water turned off at the mains.
I have asked my neighbour to flick off his mains switch to try and determine whose house this is coming from, but he is not willing to do this. How can I detect / monitor where exactly the noise is coming from.