Why isn’t there a Standard Voltage among the World’s Nations?

If you’ve ever traveled overseas, you probably already know that there isn’t a worldwide standard for the voltage and frequency of alternating current (AC) electricity. Hopefully you didn’t find out the hard way. For various reasons there are actually four standards that most countries fall under.

  • 220-240v/50Hz
  • 220-240v/60Hz
  • 100-127v/60Hz
  • 100-127v/50Hz

The majority of the western hemisphere runs on 110v/60Hz, with a few exceptions in South America. The rest of the world runs primarily on 220v/50Hz, again with some outliers (Madagascar, Japan, and Saudi Arabia, to name a few). While it would be easy to chalk up the difference in voltage standards to simple rivalries between regions, a close look into the history of electricity around the world sheds light on the real reason for the lack of a universal voltage archetype.




In the 1880’s, Edison developed the first form of voltage – direct current (DC) – primarily out of the need for an electrical distribution system to provide power to his Incandescent Light Bulb, which he invented in 1879. Direct Current is defined as a current that runs continually in a single direction, like in a battery or a fuel cell. For the remainder of the 19th century and the beginning of the 20th, 110v DC current was the voltage standard in the United States.

While the advent of DC current was a revolutionary step forward for humanity in terms of how it formed the foundation for the industrial revolution, it was not without its faults. One of the biggest shortcomings of Direct Current is that it is not easily converted to higher or lower voltages. As a result, the wires used for large-scale electrical distribution would need to carry a very large amount of current, and when electric power is delivered along a wire, higher current amounts to a lot of power being wasted in the wire. In other words, using DC current to power a city would result in approximately a 20% transmission loss.

With public interest in widespread electrical distribution networks on the rise, George Westinghouse, an American entrepreneur and engineer, found a way to capitalize on the deficiencies of DC current through the advent and endorsement of Alternating Current (AC). AC current had all the benefits of DC current without any of the large drawbacks, as AC current could be used in conjunction with a transformer for voltage conversion purposes.




Enter Nikola Tesla. Westinghouse purchased multiple patents for alternating current devices from inventors in Europe and licensed patents from Tesla, who at-the-time was a relatively unknown Serbian-American inventor and engineer. Tesla’s AC devices all ran at 240v and 60hz, instead of at 50hz because “the slower speed 50Hz electrical generators are 20% less effective than 60Hz generators. Electrical transmission at 50Hz is about 10-15% less efficient, (Kurtus, R.)” and 50hz transformers require larger windings than those made for 60hz.

With the partnership in place, AC current began to take hold as a much-improved alternative to Edison’s standard. Consequently, Edison began to feel the price of fully-endorsing an inferior product, and as a result began a campaign to discredit his competition, which included the spreading of misinformation, and even going so far as to publicly electrocute stray animals using alternating current to prove his point. So began The War of the Currents.

In 1893, Chicago held the World’s Fair, and a bidding war was held to determine who was going earn the contract to provide power the fair. While Edison’s General Electric initially held the bid for $554,000, Westinghouse eventually won out after he said he could power the fair for over $100,000 less. In the same year, Westinghouse was also awarded a contract to generate power to the entire Eastern United States using the Niagara Falls. These two events would prove to be the proverbial “nails in the coffin” for the Edison-championed DC current, and AC current has since become the worldwide electrical current standard.




But the story doesn’t end there, as the German company AEG started generating electricity and became a veritable monopoly in Europe. They decided to use 50Hz instead of 60Hz to better fit their metric standards, but they stayed with 120V current. Tesla and Westinghouse soon followed suit by converting their current from 240v/60hz to 120v/60hz.

Now you might be thinking, “doesn’t this mean that the whole world should be using 110v AC as the gold-standard of voltage distribution?” Yes it would…if the story ended there…but it doesn’t!

In the years shortly after World War II, the majority Europe and parts of Asia had to rebuild massive amounts of infrastructure. Those in charge of the rebuild effort agreed that AEG would switch over to 220v current for the purposes of better electrical transmission which created the current discrepancy that stands today. The United States considered making the same voltage switch as Europe during that time-period, but the decided against the move due to the amount of 120V electrical appliances that would have to be replaced per citizen.

So if you happen to travel to another country and plug-in an 120v appliance only to be greeted with an audible “pop” and a cloud of smoke, you now know that you can attribute the blame to two of the most important and influential inventors of the modern era, as well as those charged with rebuilding a war-torn Europe following 1945. Hopefully you’ll have done your homework in advance and won’t have to deal a blown-out appliance…but if you do, at least you’ll have learned about a little-known but important part of our history.

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