Having a floating and a grounded biphase output are two different things.
I personally have never seen a biphase output generator, with a grounded coil center, but surely possible. I would expect an inverter generator to produce a floating output.
Im not fully there, since a floating output can just as well be at the same 50% voltage level. For example due to common mode capacitors on the output.
Thats true, since all the RCD needs is that bond to ground, whether its a biphase output with grounded coil center, or a “true” neutral with a bond to ground doesnt matter.
But the main point is “ground referenced”. If the output is biphase with a grounded coil center, then adding an external N-PE connection will short circuit one half of the generator coil, which would trip the generators output breaker.
Also correct, but thats one of the main reasons that some electrical code does not allow for more than one output socket on a floating source (and prohibits the use of power strips on it). So you can only plug a single device in and still be safe without an RCD.
I guess this is the main point here. Check what type your generator is, if its output is floating or not, and if it can be grounded externally.
Yes, many. And the deeper you go into grounding the worse it gets.
But generally, the main differences are described as TN and IT networks.
Your local electrical code decides whether you need an N-PE connection or not. But be prepared to stumble into a lot of if’s and when’s as well as “it depends on the situation”. Sometimes theres no clear cut answer even from the code, so you have to decide on a system to use.
The key part is that you take that decision and stick with a system, rather than having an undefined situation where the inverter still uses its N-PE relay but the generator produces a floating output, effectivly switching systems with the ACin switching.