Flush-mounted sockets in FertigKeller

Hello everyone, are the recesses for the electrical flush-mounted boxes made at the precast concrete plant for prefabricated basements or are they drilled later on the construction site?

Thank you very much in advance for your answers

At our place, installation levels were simply created in the insulation on the exterior walls. However, it is also partly a [Wohnkeller]. The rest of the basement is surface-mounted.

At our place, an installation level was simply created in the insulation on the exterior walls.

With insulation on the inside, or how am I supposed to imagine that? In general, the concrete walls are not very suitable for usual chiseling work, but there are flush-mounted boxes that can be concreted in directly at the factory. However, this requires that all boxes and all wiring routes are determined in advance.

What was stated in the construction service description of the general contractor or in the offer of the trade.

Usually, one tries not to drill into the exterior walls but to use surface-mounted boxes, to move flush-mounted boxes into the interior boxes, or if absolutely necessary, to use the TomTom solution.

With insulation on the inside, or how am I supposed to imagine that?

Yes, inside, you naturally lose surface area inside.

These are 8cm panels with aluminum foil but don’t ask me the name anymore. On that, battens, OSB, and drywall.