Paul C, it has come up in discussion before especially when discussing an ideal/universal plug-socket system. Apparently it is mainly historical in that early European 220V supplies were derived from two phases of a 3 phase, 127V to ground wye system and thus polarity was not an issue. According to posts on this forum, there are scattered places in Western Europe where this system is still in use.

In my mind, this does not make a non-polarised, single phase, 230V to ground plug system right – but then I am a known ‘polarist’ around here [Linked Image]