I took this picture right next to where I shot the lonely swivel chair. Now I remember that the buildings where in fact part of an old electrical substation (or transformer station). The signs here (in German) warn about “danger high voltage” and enumerate the rules of how to switch off the electricity before beginning any kind of work.
I actually learnt my first trade at an electrical utility Although I did office work we were sent out with the electrical crews to learn about the work our company did. Of course we were not let anywhere near high voltage installations but we could at least observe the workers doing their tasks on the lower voltage side (which with 230V in Europe is still dangerous but survivable). The high voltages in transformer stations were very deadly. I also enjoyed exclusive tours through the power plants. Unfortunately I was not doing photography back then. It would have been a unique opportunity.
These signs here are merely decoration, The buildings are now offices for creative types and start ups. Still I like the fact that they kept them. Most large cities have a rich history of industry that is rapidly vanishing and replaced by glass and concrete office or apartment buildings. So it is great to see some buildings preserved and even used productively.