220V is the most common standard voltage rate for 50c/s power. Later on, some countries want to save cost on modify whole country wiring due to over crowded users, they jacked it up to 230V or even 240V.
I have read the other answers and they miss the main point. In Europe the supply voltage varied between countries from 220V (France, Germany, Spain etc) to 250V in the UK. The European Union considered this variation to be a barrier to free trade within the EU so they published a directive which stated that all states of the EU should have the same supply voltage. Well, this was well and truly bodged by the politicians who allowed the generators and suppliers in the EU to widen their variation on supply voltage, so now in the UK our stated supply voltage is 230 but with a permissible variation that brings us down to 220V and allows us to rise to 250V. The idiot politicians in the rest of the EU have allowed similar bodges in their countries. It plays havoc if you are an electrician trying to work out power or current as you have to use the stated voltage not the actual voltage, what a c**k up!
It drives me nuts to see "220V" or "110V" marked on devices. The standard home voltages in the United States are 120/240V
It designates the power level required to run it. Some "appliances" especially electronic ones have the ability to run over a much wider range, even 100 to 250, which is the range from one common voltage in Japan to the highest voltage expected in the USA.
I depends on what country you live in. Many European countries use 220v but, in the USA 110v is the standard.
Pls help me
