Difference Between 120V and 240V/230V AC Power Supply
240V/230V is more harmful than 120V when exposed directly to a human body. Voltage drop and I2R is higher in 120V than 240V for the same distance, wire size conductor and wattage application (Watts = Volts x Amps). Keep in mind that is negligible (3 to 5%) in home based wiring systems.