DocBrown napisał(a):What is kakelit ? Maybe you think about bakielit ?
Oh, sorry, that's my stupid mistake, of course bakielit:)
DocBrown napisał(a):This switch from your last photo is very, very nice, but this wire is awfull

Is it copper, or aluminium ? If aluminium, You should immediately replace it, and I'll reccomend you to place new wire in PVC pipe, wires should not be placed directly on the wall without any protection, especially if they have only one layer of insulation.
Wire on your photo is very dangerous, because it has only one layer of insulation, and is placed directly on flammable surface, the insulation might be in poor condition, so it makes serious risk of fire, or electric shock

Can you post photos of whole electric installation in your flat ? I'm afraid that your installation must be replaced as soon as possible, because it is very dangerous
But about wires I'll disagree with you. All instaliation in one room I made abuot 5 years ago but it's made by old technology and all elements of it are autentic and made before WW 2. Only wires are new, soft, made of copper. They are instaled on old autentic ceramic izoliators (no contact with brick wall). You are right, that wires has only one layer of insulation, but it is quite thick, so it is safe to use theese cabels in open air. No risk of fire or electric shock

Now imagine, if wires wuold be in PVC pipe, when all room is decoraded using old technologies, doors, windows and locks are autentic, furniture, switches and sockets also old - the wiew of PVC pipes in such room wuold be auful

When I was instaling that old autentic instaliation, I was looking for wires, made by autentic technology, with cloth insulation, but I cant get it in Lithuania and sending it from other cuontries was too expensive for me

Now in Vilnius opened a special electricity instaliation made by autentic old tecnologies shop, but that type of wires are very expensive there:( So I did it in the way you see and I'am not going to replace it:)
I don't know how it's in Poland (I havent seen such istaliation, besides wisiting Poland many times

), but in Lithuania instaliation technology with small isoliators was quite popular and was used from begining of XX century till 1975, so now you can find such instaliations in old houses (in my instaliation all izoliators are made before WW 2)
here are some pictures:

Here are some of my small izoliators

And two of my old bakielit switches. Black is very old, with wooden handle.

Brown is made by "Brabork":
