2.2.1 European Voltage Harmonisation
The nominal European voltage is now 230V 50 Hz (formerly 240V in UK, 220V in the rest of Europe) but this does not mean there has been a real change in the supply.
Instead, the new "harmonised voltage limits" in Europe are now:
230V -10% +6% (i.e. 207.0 V-243.8 V)
in most of Europe (the former 220V nominal countries), and
230V -6% +10% (i.e. 216.2 V - 253.0 V)
in UK (former 240V nominal)
This is really a fudge and means there is no real change of supply voltage, only a change in the "label", with no incentive for electricity supply companies to actually change the supply voltage.
To cope with both sets of limits an equipment will therefore need to cover 230V +/-10% i.e. 207-253V. This will actually become the official limit for the whole of the EU in 2003.