Technical article from Blue Sea Systems
In the US the 2 commonly supplied shore-power voltages are 120 Volts (60Hz) AC and 240 Volts (60Hz) AC. The standard in Europe is 230 Volts (50Hz) AC. The voltages will vary depending on the specific location. All of these supplies are single phase, but there are differences in the supply wire configurations and consequently in the power distribution panel structure. The chart below illustrates the differences.
Blue Sea Systems AC power distribution panels feature one hot distribution bus and single pole breakers for all branch circuits. This allows them to be used for 120V (60Hz) or 230V (50Hz), depending on the panel selected. The current panel offerings are not usable for 240V (60Hz) service, although some could be re-wired to handle 240V (60Hz) if 120V is all that is desired for branch circuits.
European ISO standards require Ground Fault protection for the entire AC system. The RCD (Residual Current Device), which provides this protection, must be placed before any circuit protection devices.
Original article from Blue Sea Systems