Single-phase voltage and frequency

Look-up table (single-phase voltage, frequency and plug/sockets)

Plugs and sockets

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Trick to know the local voltage and frequency

Three-phase voltage, frequency and number of wires

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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 A and B plugs have two flat prongs with a hole near the tip. These holes aren't there without a reason. If you were to take apart a type A or B socket and look at the contact wipers that the prongs slide into, you would find that in some cases they have have bumps on them. These bumps fit into the holes so that the outlet can grip the plug’s prongs more firmly. This prevents the plug from slipping out of the socket due to the weight of the plug and cord. It also improves the contact between the plug and the outlet. Some sockets, however, don't have those bumps but just two spring-action blades that grip the sides of the plug pin, in which case the holes aren't necessary.

There are also some special outlets which allow you to lock the cord into the socket, by putting rods through the holes. This way, for example vending machines cannot be unplugged. Moreover, electrical devices can be "factory-sealed" by the manufacturer using a plastic tie or a small padlock through one or both of the plug prong holes. For example, a manufacturer might apply a plastic band through the hole and attach it to a tag that says: "You must do X or Y before plugging in this device". The user cannot plug in the device without removing the tag, so the user is sure to see the tag.

Type A and B plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type A or B plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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 A and B plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type A or B plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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 D plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type D plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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 H plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type H plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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 J plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type J plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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 M plugs are among the most dangerous ones in the world: the prongs are not insulated (i.e. the pins don't have a black covering towards the plug body like type C, G, I, L or N plugs), which means that if a type M plug is pulled halfway out, its prongs are still connected to the socket! Little children run the risk of electrocuting themselves when pulling such a plug out and putting their fingers around it.

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.

Type N is actually based on the international standard 230 V household plug system, called IEC 60906-1. In 1986, the International Electrotechnical Commission published this standard, which was intended to become the common standard for the whole of Europe (and, by extension, all other regions with 230 V mains). Unfortunately, the effort to adopt it as a European Union standard was put on hold in the mid-1990s. Brazil had been using as many as 10 (!) different types of plugs and sockets, including the frequently used type C. In order to put an end to this proliferation of different types of sockets and plugs, the Brazilian Association of Technical Standards (Associação Brasileira de Normas Técnicas (ABNT)) published the standard NBR 14136 in 2001 and started implementing it in 2007. This Norma Brasileira 14136, however, is not completely identical to IEC 60906-1. The biggest difference is the fact that the Brazilian standard has a pin diameter of 4mm for the 10A plug and 4.8mm for the 20A plug, while the original IEC 60906-1 standard has a single pin diameter of 4.5mm and a maximum current of 16A.

Although type N plug and socket are among the safest in the world, Brazil's standardisation on one single plug and socket does entail some risks. Why? Simply because Brazil is one of the few countries that does not have a standard voltage, but at the same time it has only one official type of socket! In other words, you cannot tell the difference between a 220 V and a 127 V socket! (Click here for an exhaustive list of all 27 Brazilian federative units and their respective voltages.) Most states use 127 V electricity, but a couple of them are on 220 V. This means that a 127 V hairdryer bought in the state of Minas Gerais will be destroyed when plugged into a compatible 220 V socket in Distrito Federal! Make sure you check out the local voltage before plugging something in! (Click here for a trick to know the local voltage.) It must be said, though, that many appliances sold in Brazil are dual voltage, but that's definitely not the case for all of them.