Originally Posted by ericloewe
I'm by no means an expert but:
Yellow/Green is ground
Brown or Black is usually neutral
Blue is live
If your friend has problems with that part, he should seriously have an expert do the job.
Yellow/Green is always ground. But in old installations it may have just been bare copper.
In the pictures it looks like there are blue and brown wires which are "new" colors.
Under new colors: Blue is ALWAYS neutral, and brown is ALWAYS live (other permitted colors for live are grey and black - e.g. in 2-way switched circuits, or 3-phase wiring).
(old colors varied - a lot)
The things attached to the wires are connector blocks. European codes usually require individual screw terminals for joining wires (not wirenuts). Although low-quality DIY installations may use things like scotchloks (which are not generally recommended).