> it takes about 3 years to properly train even a "normal" residential electrician

To pass ordinary wire with predefined dimensions in exposed conduits? No way it takes more than a few weeks.

I'm talking about proper German training, not the kind of shit that leads to what Cy Porter (the home inspector legend) exposes on Youtube.

Shoddy wiring can hold up for a looong time in homes because outside of electrical car chargers and baking ovens nothing consumes high current over long time and as long as no device develops a ground fault, even a lack of a GFCI isn't noticeable. But a data center? Even smaller ones routinely rack up megawatts of power here, large hyperscaler deployments hundreds of megawatts. Sustained, not peak. That is putting a lot of stress on everything involved: air conditioning, power, communications.

And for that to hold up, your neighbor Joe who does all kinds of trades as long as he's getting paid in cash won't cut it.