In my living room there are two light switches, the cables of both come out of the same hole in the ceiling. I would like to use both switches, one for dim, ambient lighting, the other for game nights etc. Hence I installed an additional lamp.
Sadly the second lamp doesn't turn on. While my mains tester indicates that blue, brown and both black cables are live (see image), only the combination of blue and any black cable works. When attaching brown and black to a lamp, the lamp doesn't turn on.