The mass bulb production with carbonized filament is associated with Thomas Edison, the optimal voltage of which was 110v. And the first power plant of Edison in New York was 100 volt with 10 percent projected for losses in wires.
When the electricity kick-started in Europe and bulbs with metal filament first appeared, it was essential to increase the voltage. As a result, a standard 220v was applied in Germany when the electrification was made to Berlin. The argument for switching to a 220v distribution capacity was that it decreased the conductor loss by four times. Eventually, Europe went with 220v, which is no surprise as the Germans introduced the AC power in Europe. However, the cost was the main reason because higher voltage allows thinner wires, meaning less copper in the early days of power lines. Therefore, power companies could save money on the wire by using 220v rather than 110v. This is how the 220v-system (later 230v) became the European norm. Besides, contrary to 110v, 220v allows heavy-duty appliances requiring more electrical power.
| 110v | 220v |
| Uses more current but lower voltage | Uses higher voltage but lower current |
| Runs at 50Hz | Runs at 60Hz |
| 50Hz power is less effective in generation | 60Hz is more efficient in generation and transmission |
| Lower voltage requires a thicker wire | Higher voltage requires a thinner wire |
| 115,120 and 125 volts fall under a 110v system | 230, 240, and 250 volts fall under a 220-volt service |
| 110v outlet has three-pronged plugs | 220v outlet has three or four plugs |
| An outlet is visually smaller | Visually bigger and typically round |
| Only white | Dark brown or black |
| Has the lower risk of electrocution | Poses a higher risk of electrocution |