The situation in germany is essentially the same, but that's why net supply by these is limited to 800 W. I don't think anything changes w.r.t. earth leakage, why would the presence of the solar supply change anything from the RCD and fault point of views, respectively?
Not expert but one difference is that in Germany the standard wiring is radial circuits with 16A MCBs while in the UK it's ring wiring with 32A MCBs.
So in the UK we have 2.5mm^2 wires in a ring on a 32A MCBs... Of course a 2.5mm^2 wire is rated ~20A so any issues with the ring (sockets still work since connected from the other branch) can burn the wire before the MCB trips...
The "standard" wiring is 1.5mm² on 16A MCBs which are rated to trip at 1.13-1.45x nominal current (so 18-23 A). So this is already mildly improper because you can pull elevated currents continuously and dramatically shorten the life of the insulation.
We would call it "a serious code violation." It's prohibited in the NEC and always has been, it's objectively less safe.
From what I understand the UK allowed it because of a severe postwar copper shortage and it persists to this day because it's allowed and a bit cheaper.
> From what I understand the UK allowed it because ...
I'd say "severe post-WWII money shortage". After wartime expansion, the global copper industry could physically meet peacetime demands. But the UK was very close to national bankruptcy. And the Luftwaffe had turned an awful lot of their prewar housing into rubble. So - any cost that could be cut, was.
If your generator is plugged into their own circuit, it wouldn't change much.
If you plug it into an overloaded ring final (which is not uncommon in the UK - half our house's sockets are on a single ring), you have to rely on the generator being able to detect faults to protect that circuit.
You could also overload that circuit's wiring. If you have a a 16A Ecoflow, plug it into a 32A ring, you could draw 48A before tripping the grid circuit breaker, potentially causing significant heat in the wires. Dinky 3A generators won't do that but I don't think they're the limit our government are talking about.
