To begin understanding the reason for this difference, we must first consider that electricity is defined by two measurable factors: the first is voltage, measured in volts, and the second is current, measured in amperes. They are distinct; the former relates more to the “pressure” of the electrical flow, while the latter relates to the “flow” or “quantity.” Multiplying volts (pressure) by amperes (flow) yields power, which is measured in watts.
In a country with a voltage of 110, a 60-watt light bulb requires 0.54 amperes, whereas in a country that uses 220V, the same bulb needs 0.27 amperes.
The cost factor
The difference does not lie in the amount of electricity needed; what matters is the power, as that is what you pay for. This power is expressed in kilowatt-hours.
The biggest difference lies in the wiring: 220V is “less refined,” meaning it can be carried by thinner cables. Wiring a house or building for 110V is more expensive. That may well have been an initial reason why a country chose one voltage over the other. However, there is another factor to consider: safety. Obviously, an electric shock from 110V is not as dangerous as one from 220V.
The Safety Factor
In the late 19th century, industrialized nations were implementing their power transmission systems; Thomas Edison held one vision for this, while Nikola Tesla held another. Edison advocated for the use of Direct Current (DC), which operated at 100V and was difficult to convert to other voltages. Tesla maintained that Alternating Current (AC) was superior because its voltage could be easily modified—reducing costs—and it could be transmitted over long distances.
Edison attempted to discredit Tesla’s system by electrocuting animals to death, but Tesla prevailed by using himself as a human guinea pig, demonstrating at a fair that a 220V current could pass through his body without harming him. He reportedly used rubber-soled shoes and high-frequency current to achieve this.
Due to cost considerations and the ease of transmitting electrical energy, Europe and the vast majority of countries worldwide adopted a 220V standard, whereas the United States and aligned nations in the region retained 110V. Thomas Edison’s light bulbs, which operated on 110V, were already in widespread use by that time.
In addition to the differences in voltage and amperage used, the world is also divided when it comes to power outlets—but that is something we will cover in a future article.