For the UK that's correct, " In the UK, the declared voltage and tolerance for an electricity supply is 230 volts -6%, +10%. This gives an allowed voltage range of 216.2 volts to 253.0 volts." ( https://www.spenergynetworks.co.uk/pages/voltage_changes.aspx )
I've rarely come across equipment, that can't tolerate 240 +/- 10% though, the few that didn't tended to be cheap chinese imported power supplies.
Biting the hand that feeds IT
