Why are there so many different plugs and sockets?

“Why isn’t there a single plug that could be used everywhere?” is a recurrent refrain, particularly among frequent (and frequently frustrated) international travellers. The good news is that there does exist a single international plug and socket system and the IEC wrote the International Standard for it in the 1980s. For the past 20 years the Commission has been publishing a series of standards that cover plugs and socket-outlets for domestic and general similar use as well as another series that cover plugs and sockets for industrial purposes. These standards are available for any country to adopt and use as its own national standard.

So if the problem doesn’t lie in technical specifications suitable for use globally, where does it lie? Well, it’s historical.

When electricity was first introduced into the domestic environment at the end of the 19th century, it was mainly for lighting. The appearance of labour-saving electro-domestic appliances in the early 20th century pushed industry into developing a means of connection to the electricity supply other than through light sockets. The 1920s saw the first two-prong plugs being manufactured in the United States, followed some years later by three-pin plugs. This development was motivated by safety reasons. To make electrical installations in buildings safer, the third pin on the outlet was for earthing. The reasoning behind this was that in the event of a short-circuit to earth, a fuse would blow and disconnect the supply.

While two- and three-pronged plugs can be found all around the world, many countries and manufacturers did not adopt the original US design, instead preferring to develop their own products. In the pre-globalization era, this led to the growth of similarities in regions and continents as companies concentrated on serving their national and regional markets. But there are exceptions to this, too. Take Europe for example: most countries use the same plug and socket systems – common, mandatory standards in the European Union is a harmonizing factor – but the United Kingdom and Ireland have their own designs, as does Switzerland. In many African, Asian or Central American countries, the colonial heritage prevails.

In short, with vested interests built right into our walls, it might be very difficult for any government to legislate the requirement for both its construction and electrical industries, as well as its consumers, to spend great sums of money to change from one plug and socket system to another.

So it is unlikely that, in the short term, we will see a single plug and socket system in use all around the world. Perhaps in the long term, as globalization increases and as technology evolves, we may see movement towards this. For now, when you hear people complain that there isn’t there a single plug that could be used everywhere, tell them that it does exist and that the IEC standardized it. All that remains is for their government to adopt it.

How this zone works

The zone contains two main sections. The first covers IEC standardization work for plugs and sockets and provides both the historical background that led the IEC to develop specific standards along with an overview of current IEC publications. The second section gives practical information, listing the different types of domestic plugs and sockets used by different countries and featuring examples of all the plug types in use.