djk,
The supply here in NI was always 230v nominal and thus when CENELEC harmonization was introduced it was relatively unimportant. As PaulUK says there was no real effect in UK.
I have many contacts in NIE so I will run your comments by them. Discussions may have been prudent on the HV system as we have a significant network at 110kv.
Belfast used to have a 6kv system with phase rotation opposite to everywhere else in NI!
Maybe that was the start of our troubles!
Regards,
