The device for connecting to the network, which consists of an outlet and a plug connected to it, looks different in different countries of the world. The design of electrical plugs and sockets is developed depending on the standard of electrical networks.
A Brief History of Electric Plugs
The kit with which you connect household appliances to the electric current network is called a “plug connector”. It consists of:
- socket - a socket in the form of a socket to which electricity is supplied;
- plug - a device, which is fixedly mounted or connected to the device using a cable, for connecting to the mains.
A patent for a plug connection in the form of a socket and plug in 1904 was received by Harvey Hubbell. Introducing a new type of connection, he intended to replace the unsafe connection of electrical appliances with lamp cartridges (Edison's method). By about 1920, the Hubbell method began to be introduced everywhere. The invention of the Schucko contact system (Schuko), a kit consisting of a socket, grounded with staple-shaped contacts, and a power plug, helped to establish itself as a safe and simple means of delivering electricity to household appliances.
The introduction of innovations in different countries in the 20th century went hand in hand with the development and adoption of electric grid standards. They include two main parameters:
- voltage (unit - Volt);
- frequency (unit of measure - Hertz).
It is interesting that in one country both one standard and several can be used. Some countries have decided to harmonize standards. Today there are at least twelve of them.
Types of Plug Connections
Some types of outlets can plug in other types of electrical plugs. If you are going on a trip, you should not rejoice if the type of forks matches the domestic one. It is worth clarifying one question - does the standard of electric networks coincide with the one that is used in our country.
How are plug connections classified?
So, the main reason for using different types of electric plugs in different countries is the state standard for electric networks.
Type A and B (American)
In the United States, two types of electrical outlets are used: type A and type B. Type A is two-pin, type B is three-pin. Both types work under voltage of 120 V with a frequency of 60 Hz. For these outlets, Nema 5-15R type connectors are provided.
The type A plug design firmly fixes the plug in the outlet: the neutral contact is wider than the phase contact. Type A plugs can be used for both types of outlet designs. In the past, they were provided for devices that do not require grounding. In modern homes, sockets of this type are not used, because they are not safe.
Type B plugs require a flat, long grounding contact that eliminates the possibility of plugging the plug into the wall outlet incorrectly. If the appliance fails, this design of the socket eliminates the possibility of electric shock in the event of a leak: grounding will work until the consumer contacts the current.
Type D (Asian)
The plug type D, the so-called "Asian" type, the design is three circular contacts located in the shape of a triangle. Type D sockets are defined by the old British standard BS 546, which was valid in developed countries until 1962. Type D plugs are found in countries formerly in the British colonies, where the UK was involved in electrification. The socket provides grounding and is designed for amperage up to 5 A, operates under a voltage of 220-240 V.
Used in Asian countries. However, over time, this type was considered obsolete, and it was withdrawn from circulation by replacement with later versions, designed for 15 A.Connectors of this type can still be found in Sri Lanka, Burma and India, Bangladesh and Namibia. It is used mainly in developing countries and, according to various sources, make up about 15% of the use of sockets of other types in the same states.
Type G (British)
The type G plug is defined by the British standard BS 1363, which was introduced immediately after World War II - in 1946. It is large enough. By design, it consists of three large polarized contacts and a fuse hidden inside. The polar contacts are flat, rectangular in shape, with insulation at their base.
A fuse protects the power cable that carries current to the devices. This is justified by the features of the electrical wiring used in the United Kingdom. Sockets are designed for voltage 220-240 V and a standard frequency of 50 Hz. The current is allowed up to 13 A.
For connectors of this type, the design provides for the presence of protective curtains that open when the ground contact is connected. Even if the grounding of the device is not provided, in its place is a plastic imitation.
The history of the emergence of British-style sockets is associated with a shortage of copper in the period from 1941 to 1945. The structure of the connectors made it possible to save scarce metal. The presence of a built-in fuse explains the large-sized plug. According to British standards, a household electrical network allows a large current strength, therefore, grounding is necessary to ensure safety. Sockets of this type are used in the UK, Ireland, Singapore, Cyprus.
Type I (Australian)
Type I forks are also called Australian forks, as they are used primarily in Australia and New Zealand. The socket is designed for voltage up to 240 V and current strength up to 10 A, which is less safe for humans, compared, for example, with American sockets, but it is easier to implement technically. The Australian standard has undergone significant changes over time: from 1937 - C112, from 1990 - AS 3112, from 2015 - AS / NZS 3112: 2004.
According to the latest changes in the standard, by design, the type I plug is 2 flat pole-knife contacts with insulation located at a distance of 1.37 cm from each other at an angle of 30 degrees to the vertical, a house, and a grounding pin. 90% of these outlets have a switch for added safety to humans. There are also plugs with a wider grounding pin that work with currents up to 15, 20, 25 and 32 A. 20-, 25- and 32-amp plugs have a special design that is incompatible with a connector designed for less current.
Type H (Israeli)
Type H forks are called Israeli. Mains voltage up to 230 V at a frequency of 50 Hz. Sockets are designed for amperage up to 16 A. They are used exclusively in Israel and in disputed territories. Regulated by the Israeli standard SI 32 (IS16A-R).
Initially, the plug consisted of three flat contacts: neutral, phase and ground - located at an angle of 45 degrees, in the shape of a triangle or the letter Y. The distance between the polar, phase and neutral, flat pins is 1.9 cm.
Over time, practice has shown that with active use of equipment with high power consumption, flat contacts overheat, which is unsafe. So, in 1989, changes were made to the standard: flat pins were replaced with round ones with a radius of 2 mm. Despite the fact that the Israeli type sockets are three-pin and unique in this country, the connector is suitable for two-pin type C plugs - europlugs, as well as for the old type H plugs - with flat contacts.
Type K (Danish)
Danish type K forks are used mainly in Denmark and Greenland, partially represented in Bangladesh and Madagascar, Guinea, Senegal and the Faroe Islands, that is, only 2.8% of 246 countries. Visually, the Danish connector is like a smiling emoticon.The plug consists of two feeding round pins located on a round base 1.9 cm from each other. The semicircular grounding pin is also located on the plug and enters a special socket on the outlet.
The connectors, according to the design, are polarized, that is, a wire with the presence of potential - phase - of a special shape. However, a universal standard for connecting phase and neutral wires does not exist. Most outlets are equipped with a switch for safety reasons when plugging or unplugging the plug.
The socket and plug are defined by the Danish standard SRAF1962 / DB 16/87 DN10A-R. Since 2008, they must have a grounding and residual current device (HFI). Designed to operate under voltage up to 250 V, with a current strength of up to 10A and a frequency of 50 Hz.
Socket type K - a product of exclusive in Denmark company Lauritz Knudsen. So, in order to expand the market for electrical equipment, the country also uses type E sockets - with two contacts and a French-type grounding socket.
Type C and F (European)
Type C and F forks are widely used throughout the world, especially in the Russian Federation and countries of the former USSR. Plugs of various standards are suitable for type C plug connectors. Plugs C in most cases are suitable for sockets F and vice versa, however, there are significant differences between them.
Europlug type C (Europlug) consists of two round pins with a radius of 2-2.4 mm. The pins are 19 mm apart. The connector, respectively, with round holes. Grounding is not provided here. The socket is designed for voltages up to 250 V at a frequency of up to 50 Hz and a current strength of up to 2.5 A. In the technical literature, the name CEE 7/16 can be found.
A Type C plug is considered obsolete in the modern world because grounding is not provided for it, however, it is used almost everywhere in the world. The most relevant option for the current needs of humanity is the F type plug.
The type F socket is designed for high current strength - up to 16 A, operates under voltage in the range of 220-240 V, with a frequency of up to 50 Hz. Indicated in international documentation as CEE 7/4. This type of plug is also known as "Schuco" (from it. "Schutzkontakt" - protective contact). The standard was patented by German inventor Albert Buttner in 1926 and was distinguished by the presence of a grounding pin for household appliances.
Type J (Swiss)
Swiss type J connectors and plugs are regulated by SEV 1011 (ASE1011 / 1959 SW10A-R). Used in Switzerland and Liechtenstein. The Swiss plug is almost identical in design to the Euro plug (type C) and compatible with it. The difference is that the type J plug has a round grounding pin mounted offset. There are plugs without grounding, they are designed for currents up to 10 A. For a current of 16 A, a plug with an earthing contact and square pole pins is provided.
The Swiss plug is not completely harmless when used in everyday life, since the pole pins do not have insulation in the place of attachment to the base, which means that with a loose fixation of the plug in the socket, the possibility of electric shock is not excluded.
The connectors make internal and external. The internal connector has a separate plug-in design located in a box inside the wall. The external connector is mounted on the wall in a one-piece housing. J-type plugs come in different types: with tapered ends, they are suitable for both external and internal connectors, another type of pins is only for external.
Sockets operate under voltage up to 230-250 V, with a mains frequency of up to 50 Hz.
Type L (Italian)
Type L forks are called Italian because they are used in Italy and in Chile. The Italian standard CEI 23-16 / VII provides for two types of sockets designed for different amperage - 10 and 15 A. The variety of models is defined historically: until 1974, electricity was sold for different purposes at different rates.So, in the houses double counters are installed and double wiring is carried out.
Sockets of both types provide grounding. The plug is three located on the same line of contact. The pins, with a radius of 2.5 mm, are located at a distance of 26 mm from each other, in the center - between the pole pins - there is a grounding pin.
The 10 A and 15 A plugs differ only in size, 15 A larger. Sockets for sockets do universal for both models. They are also suitable for type C plugs. Sockets are rated for 220-240 V. The fuse is not designed. Sockets can be installed both horizontally and vertically.
An interesting fact is that type L sockets inside the country are sometimes called industrial, although they have never been used in production.
Since Italy is integrated into the European Union, universal sockets are currently popular, which are suitable for both classic Italian plugs and common Europlug and Schuko plugs.
Residents of Russia and the CIS countries, where a common standard is used, will not have to adapt to new plugs and sockets, having arrived in most European, on the African Mediterranean, in India, China, Turkey and Thailand. Having carefully studied the map indicating which countries use the standards and plug connections, travelers will save themselves from additional problems and costs.
