Living in London

The electrical voltage is different in the US and Europe. In fact, it is different all over the world. In Japan and most of the Americas the voltage is between 100 and 127 volts. In the rest of the world it is between 200 and 240 volts. Some countries have an alternating current of 50 Hz (cycles per second) and others, like the US, use 60 Hz. Of course, the plugs and sockets are different in most countries as well.

I planned to do a little research on the internet and then write a concise post on why one system was better than the other. Alas, the explanations are more political than scientific.

In the early 1900's Nikola Tesla, a genius ahead of his time, did a number of experiments with electricity. He is credited with creating alternating current and the induction motor. Through his research he concluded that 240 volts at 60 Hz was the best for efficient generation and transmission. It is natural to assume at this early stage in the life of electricity that all the world would follow with 240 Volts at 60 Hz. If only life were that simple.

In the US, Tesla's preference for 240 volts put him at odds with Thomas Edison who already had several patents on devices that ran on 110 Volts. Edison was more politically powerful than Tesla and 110 volts, 60 Hz became the standard.

Originally, Europe was slated for 110 volts as well and a German company, AEG, built the first European generating facility based on 110 volts. However, since they used the metric system, the AEG engineers preferred 50 Hz over 60 Hz because 50 fit neatly into multiples of 10. This turns out to be an unfortunate choice. 50 Hz is 20% less efficient in generation and 10-15% less efficient in transmission. In order to boost the efficiency they doubled the voltage to 240.

Now we have a hodge podge of voltages and plugs in use around the world. Only a handful of countries (Peru, Ecuador, Guyana, the Philippines and South Korea) follow Tesla’s advice and use the 60 Hz frequency together with a voltage of 220-240 V.

Many thanks to the World Standards site for the excellent information on voltage and frequency as well as sockets and plugs.