TYPE A

This class II ungrounded plug with two flat parallel prongs is pretty much standard in most of North and Central America. At first glance, the Japanese plug and socket seem to be identical to this standard. However, the Japanese plug has two identical flat prongs, whereas the US plug has one prong which is slightly larger. Therefore it is no problem to use Japanese plugs in the US, but the opposite does not work often. Furthermore, Japanese standard wire sizes and the resulting current ratings are different than those used on the American continent.

TYPE B

This is a class I plug with two flat parallel prongs and a grounding pin (American standard NEMA 5-15/Canadian standard CS22.2, n°42). It is rated at 15 amps and although this plug is also standard in Japan, it is less frequently used than in North America. Consequently, most appliances sold in Japan use a class II ungrounded plug. As is the case with the type A standard, the Japanese type B plugs and sockets are slightly different from their American counterparts.

An ungrounded version of the North American NEMA 5-15 plug is commonly used in Central America and parts of South America. It is therefore common for equipment users to simply cut off the grounding pin that the plug can be mated with a two-pole ungrounded socket.

TYPE C

TYPE D

India has standardised on a plug which was originally defined in British Standard 546 (the standard in Great Britain before 1962). This plug has three large round pins in a triangular pattern. It is rated at 5 amps. Type M, which has larger pins and is rated at 15 amps, is used alongside type D for larger appliances in India, Sri Lanka, Nepal and Namibia. Some sockets can take both type M and type D plugs.

Although type D is now almost exclusively used in India, Sri Lanka, Nepal and Namibia, it can still occasionally be found in hotels and theatres in the UK and Ireland. It should be noted that tourists should not attempt to connect anything to a BS546 round-pin outlet found in the UK or Ireland as it is likely to be on a circuit that has a special purpose: e.g. for providing direct current (DC) or for plugging in lamps that are controlled by a light switch or a dimmer.

TYPE E

TYPE F

Plug F, known as CEE 7/4 and commonly called "Schuko plug", which is the acronym of "Schutzkontakt", a German word meaning "earthed/grounded contact". The plug was designed in Germany shortly after the First World War. It is similar to C except that it is round and has the addition of two grounding clips on the side of the plug. It has two 4.8 mm round contacts on 19 mm centres. Because the CEE 7/4 plug can be inserted in either direction into the receptacle, the Schuko connection system is unpolarised (i.e. line and neutral are connected at random). It is used in applications up to 16 amps. Above that, equipment must either be wired permanently to the mains or connected via another higher power connector such as the IEC 309 system. In order to bridge the differences between sockets E and F, the CEE 7/7 plug was developed (see photo above). This plug, which is shown above, has grounding clips on both sides to mate with the type F socket and a female contact to accept the grounding pin of the type E socket. The original type F plug, which does not have this female contact, is still available at the DIY shops but only in a rewireable version. A type C plug fits perfectly into a type F socket.

TYPE G

This plug has three rectangular prongs that form a triangle. British Standard BS 1363 requires use of a three-wire grounded and fused plug for all connections to the power mains (including class II, two-wire appliances). British power outlets incorporate shutters on line and neutral contacts to prevent someone from pushing a foreign object into the socket.

The British domestic electrical system uses a ring circuit in the building which is rated for 30 amps (5 amps for lighting circuits which are usually spurs). Moreover, there is also a fusing in the plug; a cartridge fuse, usually of 3 amps for small appliances like radios etc. and 13 amps for heavy duty appliances such as heaters. Almost everywhere else in the world a spur main system is used. In this system each wall socket, or group of sockets, has a fuse at the main switchboard whereas the plug has none. So if you take some foreign appliance to the UK, you can use an adaptor, but technically it must incorporate the correct value fuse. Most would have a 13 amps one, too big for the computer for example. BS 1363 was published in 1962 and since that time it has gradually replaced the earlier standard plugs and sockets (type D) (BS 546).

British plugs are no doubt the safest in the world, but also the most hulking and cumbersome. That's why people often make fun of them saying that British plugs are mostly bigger than the appliance they're connected to...

TYPE H

This plug is unique to Israel. It has two flat prongs like the type B plug, but they form a V-shape rather than being parallel. Type H plugs have got a grounding pin as well and are rated at 16 amps. In 1989 Israel standardised on a new version of the type H socket: the holes were made round in order to accommodate type C plugs as well. The slots for the prongs have widenings in the middle specifically to allow type C prongs to fit in. The flat-bladed type H plugs (lower picture) are currently being phased out in favour of round-pinned ones (upper picture). This plug is also used in the West Bank and all of the Gaza Strip.

TYPE I

This plug has also a grounding pin and two flat prongs forming a V-shape. There is an ungrounded version of this plug as well, with only two flat V-shaped prongs. Australia’s standard plug/socket system is described in SAA document AS 3112 and is used in applications up to 10 amps. A plug/socket configuration with rating at 15 amps (ground pin is wider: 8 mm instead of 6.35 mm) is also available. A standard 10 amp plug will fit into a 15 amp outlet, but a 15 amp plug only fits this special 15 amp socket. There is also a 20 amp plug whose prongs are wider still. A lower-amperage plug will always fit into a higher-amperage outlet but not vice versa. Although there are slight differences, the Australian plug mates with the socket used in the People's Republic of China (mainland China).

TYPE J

Switzerland has its own standard which is described in SEC 1011. This plug is similar to C, except that it has the addition of a grounding pin. Type J looks very much like the Brazilian type N standard, but it is incompatible with it since type J has the earth pin further away from the centre line than type N (5 mm instead of 3 mm). This connector system is rated for use in applications up to 10 amps. Above 10 amps, equipment must be either wired permanently to the electrical supply system with appropriate branch circuit protection or connected to the mains with an appropriate high power industrial connector. A type C plug fits perfectly into a type J socket.

TYPE K

TYPE L

TYPE M

This plug resembles the Indian type D plug, but its pins are much larger. Type M is rated at 15 amps. Although type D is standard in India, Sri Lanka, Nepal and Namibia, type M is also used for larger appliances. Some sockets over there can take both type M and type D plugs. Type M is also used in Israel for heavy appliances such as air-conditioning circuits (in cases where wall-mounted units are plugged in to a dedicated socket) and certain types of washing machines.

TYPE N

The above type N socket and plug are the official standard in Brazil. This standard was gradually phased in between 2007 and 2010. Type N looks very much like the Swiss type J standard, but it is incompatible with it since type N has the earth pin closer to the centre line than type J (3 mm instead of 5 mm). Type N consists of two pins and a grounding pin. There are two versions: one is rated at 10 amps and has got a pin diameter of 4 mm. The second version, rated at 20 amps, is used for heavier appliances and has a 4.8 mm pin diameter. Type N sockets were specifically designed to accommodate the ubiquitous type C plugs as well.