I've just replaced a ceiling light - one of the few left from before we bought the house.
I took it off the ceiling, and was shocked to find a single cable connected to it, and another one tucked neatly in the hole in the ceiling.
Which turned out not to be live. Or grounded.
Looking at the switch end showed the lighting ring goes that way, and the light is on a switched spur. There's also a spare cable in the back of the switch box not connected to anything...
It took some ingenuity so I could test that these two loose ends were opposite ends of the same cable. Why did the ****s put it there at all?
I also found that our kitchen fitters have broken the door of the fusebox. It stays on OK when shut, but tends to fall off when the door it opened. But we have bigger problems with them.
Andy