In article ,
JB writes:

You can eliminate Denmark for a start.

Why's that? (I've never been there).

Denmark is one of the countries which has some supplies where
neither main conductor is near ground potential. Some supplies
are 3-phase 230V delta (meaning you get the 230V between phases
and there's no 'neutral'). One leg of the delta is grounded
(so I suppose you could say 2 of the possible 3 230V supplies
have a neutral), but the other 230V supply has neither terminal
near ground potential as they'll both be around 132V from ground.

--
Andrew Gabriel