In North America we have both 110 and 220, the latter being for larger appliances. So is the American 220 identical to European 220?
This site says no...
In the US, the typical residential supply is 120 -0-120, ie. a 240 V transformer secondary with a grounded center tap. So, you will get a nominal 120 V from earth ground to either hot terminal. Normal residential utility outlets deliver only one of these hot wires, so you get 120 V hot, and a grounded neutral. This is single-phase power. Rarely do single family residences have 3-phase power, but it is much more common in apartment buildings to have 3-phase available. In those cases, you often have a 120-208 V (Wye) system, where any hot to hot wire measures 208 V, while any hot to neutral measures 120 V.
Much of Europe delivers 3-phase power to most residences, and is similar to the US Wye system, except the voltages are 230 V line to neutral, and 400 V line to line.
But, there's LOTS of variations in certain countries.
The US also has some odd systems in older industrial settings, often called open-delta. One uses one center-tapped residential transformer to give both 230 V 3-phase power AND 120-0-120 single-phase supply for office loads from the same transformers and panel. That is called center-grounded open-delta. There is also a system called corner-grounded open-delta, that only gives 230 V 3-phase (or a choice of 230 V single phase loads). These can be hooked up with 2-pole breaker panels, the same as used in residential service.
Jon