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Ever wondered why some of the appliances come with 2-pin plugs while others are 3-pin plugs?
Apparently, when electricity was first introduced into the domestic environment, it was primarily for lighting. However, as it became a viable alternative to other means of heating, plus the development of labour saving appliances, a means of connection to the supply other than via a light socket was required. In the 1920s, the two-pin plug made its appearance.
At that time, some electricity companies operated a split tariff system where the cost of electricity for lighting was lower than that for other purposed, and this led to low wattage appliances (e.g. hair dryers, vacuum cleaners etc.) being connected to the light fitting.
As the need for safer installations grew, three-pin outlets were developed. The third pin on the outlet was an earth pin, which was effectively connected to earth (this being at the same potential as the neutral supply line). The idea behind it was that in the event of a short circuit to earth, a fuse would blow, thus disconnecting the supply.
The reason why we are now stuck with no less than 13 different styles of plugs and wall outlets, is because many countries preferred to develop a plug of their own, instead of adopting the U.S. standard. Moreover, the plugs and sockets are only very rarely compatible, which makes it often necessary to replace the plug when you buy appliances abroad.
For more information on the different types of plugs used in different countries, you can visit this website: http://www.travel-images.com/
Originally answered by Ms Eleaner Ang, Librarian, Adult and Young People’s Services
Posted by Yen Yen Toh, Librarian, Adult and Young People’s Services
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