Anyone who has traveled between the United States and Europe has been faced with the challenge of making things like hair dryers work in the different countries. It’s common knowledge that you’ll need an adapter, but most people don’t know why electrical outlets vary between Europe and the U.S.
Probably the easiest explanation is that the development of electricity throughout the world happened at about the same time for most countries. Since there were no conformity standards or real communication on how to create and construct electrical wiring and outlets, electricity varies from the U.S. to Europe. In fact, it actually can vary from one European country to another.
The EU uses a 230V, and although the voltage can vary across countries, appliances pretty much work across all borders. In the U.S. 110V to 220V is used. The design of the sockets can vary radically, so multiple adapters are needed to move about the world with personal electrical appliances.
Another detail is that the Europeans needed to save copper after WWII, so it’s possible to see a large, square pinned plug with a built in fuse in some places. Another challenge in Europe is that various countries make use of two and three pin plugs, so not only will an adapter for European electrical wiring be needed by the American tourist, but he may need multiple adapters!
Another difference between the U.S. and Europe is the frequency of the electricity. In the U.S. the standard is 60Hz, and in Europe, it is 50Hz. If the electrical outlets can be adapted, there may still be a power problem due to the frequency differences.
It’s unlikely that the world, or even the EU will every be completely standardized, so the best thing a traveler can do is research. Know what adapters will be needed in the countries to be visited.