I was asking for location 'cause all receptacles were British.
At the low maximum current out of the small genny the magnetic part of a normal breaker might not work at all even in a TN-S system. In this case in Germany you will install an RCD at any rate "as maximum short current is not sufficient" for fast tripping of breaker.
Of course I would recommend a TN-S system for this application.
A separate earthing of every machine in one workshop will be a "code violation" in German eyes.
