And some parts of EU still actually have 220V. There's no major practical difference between 220V/230V/240V, it's just that different parts of the world came up

And some parts of EU still actually have 220V. There's no major practical difference between 220V/230V/240V, it's just that different parts of the world came up with slightly different standards. As standardization has progressed, now all of EU is on a nominal 230V ± 6% 50Hz -- in practice the countries are still supplying their old voltages. 230 is presently 220 in Hungary and 240 in UK. Since both are within the mandated 6%, this doesn't cause problems. Eventually, as parts of the grid are serviced and replaced, it will be transformed into unified 230V.