I found the comments regarding checking your power supply quite interesting - I guess in Europe with 220V as standard we don't really need to worry about it? (Assuming your plugs aren't on a lighting ring or something silly like that)
I once had a blade server chassis delivered with a cable for this.
Fwiw; Europe did standardize on 230V back in 1992. 220V hasn't been used in a generation or so.
There are many places where the power stations have not been updated for many years, so 220 V remains the actual voltage that can be measured on the outlet.