standard house current in most of Europe is 220 volts so everything like lightbulbs and coffee pots are 220 volts. In the US, residential wiring is basically 110. There are 3 wires comming into an average US house. The two black wires are both 110 measured to the neutral and 220 volts measured between themselves. All the normal outlets are connected between one of the blacks and neutral. For hi-power appliances, they connect across both blacks.
The European eqivalent is just 2 wires comming in - 220 and neutral. (I'm ignoring any grounds for this discussion) so every outlet is 220.
There are good arguements for both systems but the key is they are different. The standard color codes are different and the ones described for this welder are not the US standard.
If you have ever wondered why most computers have a switch on the back for 110 or 220, it is because they are used all over the world and have to cope with the different power setups.