About Electrical Outlets
Electrical outlets are everywhere. They are so commonplace that people take them for granted, even so far as to be irritated when an old coffee shop doesn't have plenty of them for hooking up a laptop. Despite this ubiquity, few people actually understand how this most basic manifestation of the electrified world works. Does this Spark an idea?
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Identification
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Electrical outlets are also known as power points, power sockets, wall outlets and electrical sockets. As a practical matter, they are all the female half of an electrical connection, with the slots or holes for accepting the prongs or pins of the male half of that connection. The male half always belongs to the electrical device. It is always done this way for the most elementary reason: electrical outlets are invariably wall or ceiling-mounted, and placing electrified, exposed prongs in such locations poses a serious hazard.
Basic Design: Three Contacts
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All wall sockets share a basic design feature in that they have three contact wires. The first is a live wire, sometimes called the hot or active wire. This carries electrical current into the building to your electrical devices. The second contact wire is a neutral wire, which "returns" the current. Practical use of electricity requires this sort of loop-like design. The third contact wire is the ground wire, which only carries electricity in the event of a fault. It is usually connected to parts that may come into contact with people and is a safety feature meant to carry electricity away from where it can do harm.
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Power Sockets and Voltage
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The world operates on two different standards when it comes to the voltage of the AC current that flows into electrical outlets, and this is the first consideration differentiating power sockets internationally. The U.S. uses 120 volts, with similar standards of 100-130 volts being widely used in Japan, Taiwan and across the Western Hemisphere (although there are exceptions, such as in Argentina). 220-240 volts is used everywhere else. This is why American electronic devices taken to Europe and elsewhere require a voltage converter to "step down" the AC current from 220 volts to 120. If the voltage was the same, but the pin designs were different, than a mere socket adapter would be the only hardware required to use the electrical outlet.
NEMA Connectors
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This is the socket style widely familiar to Americans. The basic version consists of two flat, vertically-aligned prongs, with a second consisting of the familiar pair of prongs and a third round pin mounted beneath them. The difference is that the first, two-prong design is ungrounded, whereas the two prong and one pin design is grounded. There are other NEMA sockets in use, but these are usually for specialized devices.
Other Countries
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Europe's standard is called the "Europlug," which uses a two pin system. This is sometimes an ungrounded outlet (depending on the plug inserted into it), which has led France, Belgium, Poland, Czech Republic, Slovakia and Denmark to adopt a new system where the socket has two holes for the live and neutral pins of the appliance, but also a grounding pin built into the socket. This new outlet is not compatible with Europlug devices. The U.K. uses a three triangular prong system, which is also in widespread use around the world. Israel, Denmark, Switzerland, and Italy all have unique outlet designs that are not used anywhere else. In the case of these countries, outlets are in use side-by-side with other pan-European examples.
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