Even over here in European area we do have issue with backfeeded generatours as well. they are no differnt than Americians do with their backfeeded set up.
I have see few small portable generatours blow up from illegal backfeed when the uility system got the power back on.
The lineperson over here in France the EDF ( French POCO ) have one common rules treat them as alive and ground them out ( on primay line )
And I have done quite few repairs from backfeeded generatours and the generatour itself is toasted as useal which I do expect that ( few case the stator will rip apart )
For backfeeded larger unit genrally it will be 50-50 split useally either breaker will trip or stall or damage the generatour or even worst is destory the prime mover aka engine and I have see some funky mess with it.
So., Basically never ever I say never backfeed in the building system at all unless you have proper transfer switch., end of that conneries.
The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )
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