Live or Phase

Neutral

Earth/Ground

Differences in terminology

History of plugs and sockets

Proliferation of standards

World maps by plug/socket and voltage/frequency

Types of plug and sockets

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Type A (North American/Japanese 2-pin)

NEMA 1-15 (North American 15 A/125 V ungrounded) Standardized by the U.S. National Electrical Manufacturers Association and adopted by 38 other countries, this simple plug with two flat parallel pins, or blades, is used in most of North America and on the east coast of South America on devices not requiring a ground connection, such as lamps and "double-insulated" small appliances. NEMA 1-15 sockets have been prohibited in new construction in the United States and Canada since 1962, but remain in many older homes and are still sold "for replacement use only". Type A plugs are still very common because they're compatible with type B sockets.
   Early designs could be inserted either way, but some modern ones prevent the neutral pin from being inserted into the live socket by making it wider than the live one, referred to as a polarized plug. (Note that this isn't the same as positive/negative polarization in a direct current system.) New polarized plugs won't fit in old type A sockets, but both old and new type A plugs will fit in new type A and type B sockets. Some devices that don't distinguish between neutral and live, such as sealed electronic power supplies, are still sold with both pins narrow. When attaching a new polarized plug to a cord, it's useful to remember that the most common type of two-conductor cord for low-power use in North America has smooth insulation on the "hot" side and ribbed insulation on the "neutral" side.

JIS C 8303, Class II (Japanese 15 A/100 V ungrounded) The Japanese plug and socket are identical to NEMA 1-15. However, the Japanese system incorporates stricter dimensional requirements for the plug housing, different marking requirements, and mandatory testing and approval by MITI or JIS.
   Some older Japanese outlets and multiplug adapters are non-polarized -- the slots in the sockets are the same size - and will only accept non-polarized plugs. Japanese plugs should be able to fit into modern North American outlets without trouble, but North American appliances with polarized plugs may require adapters or replacement non-polarized plugs to connect to older Japanese outlets; or even replacement of the wall socket itself.
   Japanese standard wire sizes and the resulting current ratings are somewhat different from those used elsewhere in the world. Japanese voltage is only 100 volts - lower than American voltage - and the frequency in eastern Japan is only 50 hertz instead of 60, so even if a North American plug can be inserted into a Japanese socket, it doesn't always mean the device will work properly.

Type B (American 3-pin or U-ground)

NEMA 5-15 (North American 15 A/125 V grounded) The type B plug has two flat parallel blades like type A, but has a round ground or earthing pin (American standard NEMA 5-15/Canadian standard CSA 22.2, № 42). and is also defined in Italian standard CEI 23-5 and Russian standard GOST 7396 The Europlug is used in Class II applications throughout continental Europe (Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Macedonia, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey). It is also used in Middle East, most of Africa, Argentina, Chile, Uruguay, Peru, Bolivia, Brazil, Bangladesh, Indonesia, Pakistan as well as the former Soviet republics, and many developing nations.
   This plug is intended for use with devices that require 2.5 A or less. Because it can be inserted in either direction into the socket, live and neutral are connected at random.
   The separation and length of the pins allow its safe insertion in most CEE 7/17, French type E, Type H (Israeli 3-pin), CEE 7/4 (Schuko), CEE 7/7 and Type L (Italian 3-pin) outlets.

CEE 7/17 (German/French 16 A/250 V unearthed) This plug also has two round pins but the pins are 4.8 mm in diameter like types E and F and the plug has a round plastic or rubber base that stops it being inserted into small sockets intended for the Europlug. Instead, it fits only into large round sockets intended for types E and F. The base has holes in it to accommodate both side contacts and socket earth pins. It is used for large Class II appliances. Used in South Korea for all domestic non-earthed appliances, it's also defined in Italian standard CEI 23-5.

BS 4573 (UK shaver) In the United Kingdom and Ireland, there's a special version of the type C plug for use with shavers (electric razors) in bath or shower rooms. It has 5 mm diameter pins 16.6 mm apart, and the sockets for this plug can often take unearthed CEE 7/16, US and/or Australian plugs as well. Sockets are often able to supply either 230 V or 115 V. In wet zones, they must contain an isolation transformer compliant with BS 3535.

Variations in sockets Some Type C sockets can only take 4 mm pins or have plastic barriers in place to prevent Schuko or French plugs from entering. However, many can take 4.8 mm pins and have enough room for a 4.8 mm pin round Schuko or French plug to be inserted, with an unsafe result.

Type D (Old British 3-pin)

BS 546 (5 A/250 V earthed) India / Pakistan has standardised on a plug which was originally defined in British standard BS 546. It has three large round pins in a triangular pattern. The BS 546 standard is also used in parts of the Middle East (Kuwait, Qatar) and parts of Asia and the Far East that were electrified by the British. This type was also previously used in South Africa, but has been phased out in favour of the 15 A version there. Similarly, in Ghana, Kenya, and Nigeria, the plug has been mostly replaced by the British 3-pin (Type G). This 5 A plug, along with its 2 A cousin, is sometimes used in the UK for centrally switched domestic lighting circuits, in order to distinguish them from normal power circuits.

BS 546 (15 A/250 V earthed) This plug is sometimes referred to as type M, but it's in fact merely the 15 A version of the plug above, though its pins are much larger at 7.05 mm × 21.1 mm. Live and neutral are spaced 25.4 mm apart, and earth is 28.6 mm away from each of them. Although the 5 A version is standard in India, Pakistan, Sri Lanka, Nepal, and Namibia, the 15 A version is also used in these countries for larger appliances. Some countries like South Africa use it as the main domestic plug and socket type, where sockets always have an on–off switch built into them. The Type M is almost universally used in the UK for indoor dimmable theatre and architectural lighting installations. It is also often used for non-dimmed but centrally controlled sockets within such installations. The main reason for doing this is that fused plugs, while convenient for domestic wiring (as they allow 32 A socket circuits to be used safely), are not convenient if the plugs and sockets are in hard-to-access locations (like lighting bars) or if using chains of extension leads (since it's hard to figure out which fuse has blown). Both of these situations are common in theatre wiring. This plug is also widely used in Israel, Singapore, and Malaysia for air conditioners and clothes dryers.

Type E (French 2-pin, female earth)

French type E France, Belgium, Poland, Czech Republic, Slovakia (after 1 July 2008 also Denmark) and some other countries have standardised on a socket which isn't compatible with the CEE 7/4 socket (type F) that's standard in Germany and other continental European countries. The reason for incompatibility is that earthing in the E socket is done by a round male pin permanently mounted in the socket. Sockets are installed with the earth pin upwards and wired with left as live and right as neutral. The plug itself is round with two round pins measuring 4.8 × 19 mm, spaced 19 mm apart and a hole for the socket's earth pin. It will accept Europlug and CEE 7/17 plugs.
   As with the German plug below this plug will fit some other types of socket either easily or with force. However, there's no earth connection with such sockets. Also in some cases forcing the plug in may damage the socket.

Type F (German 2-pin, side clip earth)

CEE 7/4 (German "Schuko" 16 A/250 V earthed)Schuko plug", is like type E except that it has two earthing clips on the sides of the plug instead of a female earth contact. The Schuko connection system is symmetrical and allows live and neutral to be reversed. The socket also accepts Europlugs and CEE 7/17 plugs. It supplies up to 16 amperes. Above that, equipment must either be wired permanently to the mains or connected via another higher power connector such as the IEC 309 system. It's also used in Spain and Portugal.
   "Schuko" is an abbreviation for the German word Schutzkontakt, which means "Protective (that is, earthed) contact".
   Although Schuko sockets are unpolarized, it's recommended to wire them the same way French sockets are wired (live on left and neutral on right, when looking at the socket), but unfortunately, phase wiring isn't yet officially standardised in most of the countries that use this socket type (please see the main Schuko article for details).

Gost 7396 (Russian 10 A/250 V earthed) The countries of the CIS use a standard plug and socket similar to the Schuko standard, defined in Russian Standard Gost 7396. The contacts are also 19 mm apart, but the diameter of the pins is 4.0 mm instead of 4.8 mm. And hence the connectors are rated at 10 rather than 16 amps. It is possible to insert Russian plugs into Schuko outlets, but Russian sockets won't accept type E or F plugs because the holes are too small. This socket also accepts Europlugs, but doesn't accept CEE 7/17 plugs because they use the larger pin size.
   Many official standards in Eastern Europe are virtually identical to the Schuko standard. One of the protocols governing the reunification of Germany required that the DIN and VDE standards would prevail without exception, so the former East Germany had to conform to the Schuko standard. Most other Eastern European countries use the Schuko standard internally but, prior to its collapse, they exported large volumes of appliances to the Soviet Union with the Soviet standard plug installed. Because of that, many of the Russian plugs found their way into other Eastern European countries.

Type E and F hybrid

CEE 7/7 (French/German 16 A/250 V earthed) In order to bridge the differences between sockets E and F, the CEE 7/7 plug was developed. It has earthing clips on both sides to connect with the CEE 7/4 socket and a female contact to accept the earthing pin of the type E socket. It's also used in Spain and Portugal. Nowadays, when appliances are sold with type E/F plugs attached, the plugs are CEE 7/7 and non-rewirable. This means that the plugs are now identical between countries like France and Germany; only the sockets are different.
   Type E and F plugs that are not compatible with both types of socket are only found if a cheap replacement plug has been attached to a cord that originally had another plug. Better-quality replacements are standard CEE 7/7 and are compatible with both Schuko and French standard sockets.
   Note that the CEE 7/7 plug is polarized to prevent the live and neutral connections from being reversed when used with a type E outlet, but allows polarity reversal when inserted into a type F socket. The plug is rated at 16 A. Above that, equipment must either be wired permanently to the mains or connected via another higher power connector such as the IEC 309 system.

Type G (British 3-pin)

BS 1363 (British 13 A/230-240 V 50 Hz earthed and fused) The British Standards 1363 plug. This design isn't only in used in the United Kingdom and Ireland, but also in Sri Lanka, Bahrain, UAE, Qatar, Yemen, Oman, Cyprus, Malta, Gibraltar, Botswana, Ghana, Hong Kong, Macau, Brunei, Malaysia, Singapore, Kenya, Uganda, Nigeria, Iraq, Tanzania and Zimbabwe. BS 1363 is also standard in several of the former British Caribbean colonies such as Belize, Dominica, St. Lucia, St. Vincent and Grenada. It is also used in Saudi Arabia in 230v installations although 110V installations using the NEMA connector are more common.
   This plug, commonly known as a "13-amp plug", is a large plug that has three rectangular prongs forming a triangle. Live and neutral are 4 × 6 × 18 mm spaced 22 mm apart. 9 mm of insulation over the base of the pins prevents people from touching a bare connector while the plug is partly inserted. Earth is 4 × 8 × 23 mm.
   The plug is unusual in that it has a fuse inside, for protection, in addition to a circuit breaker in the distribution panel. The fuse is required to protect the cord, as British wiring standards allow very high-current circuits to the socket. Accepted practice is to choose the smallest standard fuse (3 A, 5 A, or 13 A) that will allow the appliance to function. Using a 13 A fuse on an appliance with thin cord is considered bad practice. The fuse is 1 inch long, conforming to standard BS 1362.
   UK wiring regulations (BS 7671) require sockets in homes to have shutters over the live and neutral connections for safety reasons (for example to prevent children from inserting metal objects into them). These are incorporated into all BS 1363 sockets and are opened by the insertion of the (longer) earth pin. The shutters also help prevent the use of plugs made to other standards. On plugs for Class II appliances that don't require an earth, the pin is often plastic and serves only to open the shutters and to enforce the correct orientation of live and neutral. It is sometimes possible to open the shutters with a screwdriver to insert other plug types but this should be avoided as such plugs won't have a fuse.
   Recently the UK standard specification has been altered from the old 240V AC to a nominal 230V AC to come into line with the rest of Europe. The permitted variation in the new specification is large enough that the supply hasn't actually had to be changed.
   BS 1363 plugs and sockets started appearing in 1946 and BS 1363 was first published in 1947. By the end of the 1950s, it had replaced the earlier standard (type D) (BS 546) in new installations, and by the end of the 1960s, most earlier type D installations had been rewired to BS 1363 standards. Socket-outlets usually include switches on them for convenience. BS 1363 is considered a very safe system, but the plugs are much larger and heavier than corresponding Euro plugs.

Type H (Israeli 3-pin)

SI 32 (Israeli 16 A/250 V earthed) This plug, defined in SI 32 (IS16A-R), is unique to Israel and is incompatible with all other sockets. It has three flat pins to form a Y-shape. "Live" and "Neutral" are spaced 19 mm apart. The Type H plug is rated at 16 A but in practice the thin flat pins cause the plug to overheat when connecting large appliances. In 1989, the SI 32 was revised to use three round 4 mm pins in the same locations as the older standard. Sockets made since 1989 accept both flat and round pins in order to be compatible with both old and new plugs. This also allows the Type H socket to accommodate type C plugs which are used in Israel for non-grounded appliances. Older sockets, from about the 1970s, have both flat and round holes for "Live" and "Neutral" in order to accept both Type C and Type H plugs. As of 2008, "pure" Type H sockets (which accept only old standard Type H plugs) are very rare in Israel.
   This plug is also used in the areas controlled by the Palestinian National Authority in the West Bank and all of the Gaza Strip.

Type I (Australian/New Zealand & Chinese/Argentine 2/3-pin)

AS 3112 (Australian 10 A/240 V) This plug, used in Australia, New Zealand, Fiji and Papua New Guinea, has an earthing pin, and two flat pins forming an upside down V-shape. The flat blades measure 6.5 × 1.6 mm and are set at 30° to the vertical at a nominal pitch of 13.7 mm. Australasian wall sockets almost always have switches on them for extra safety, as in the UK. An unearthed version of this plug with two angled power pins but no earthing pin is used with small double-insulated appliances, but the power (wall) outlets always have three pins, including an earth pin.
   There are several AS/NZS 3112 plug variants, including one with a wider earth pin used for devices drawing up to 15 A; sockets supporting this pin will also accept 10 A plugs. There is also a 20 A variant, with all three pins oversized, and 25 and 32 A variants, with the 20 A larger pins and the earthing pin forming an inverted "L" for the 25 A and a horizontal "U" for the 32 A (the 5 variants will accommodate all the plugs that are equal or of a lesser current carrying capacity, but not a higher value; for example a 10 A plug will be accommodated by all sockets but a 20 A plug will fit only 20, 25 and 32 A outlets).
   Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as a formal standard in 1938), which was superseded by AS 3112 in 1990. As of 2005, the latest major update is AS/NZS 3112:2004, which mandated insulated pins by 2005. However, equipment and cords made before 2003 can still be used.

CPCS-CCC (Chinese 10 A/250 V) Although the pins on the Chinese plug are 1 mm longer, the Australasian plug can be used with mainland Chinese socket. The standard for Chinese plugs and sockets is set out in GB 2099.1–1996 and GB 1002–1996. As part of China's commitment for entry into the WTO, the new CPCS (Compulsory Product Certification System) has been introduced, and compliant Chinese plugs have been awarded the CCC (China Compulsory Certification) Mark by this system. The plug is three wire, grounded, rated at 10 A, 250 V and used for Class 1 applications.
   In China, the sockets are installed upside down relative to the Australian one.
   China also uses American/Japanese "Type A" sockets and plugs for Class-II appliances. However, the voltage across the pins of a Chinese socket will always be 220, no matter what the plug type.

IRAM 2073 (Argentine 10 A/250 V) The Argentine plug is a three-wire earthed plug rated at 10 A, 250 V defined by IRAM and used in Class 1 applications in Argentina and Uruguay.
   This plug is similar in appearance to the Australasian and Chinese plugs. The pin length is same as the Chinese version. The most important difference from the Australasian plug is that the Argentine plug is wired with the live and neutral contacts reversed.

Type J (Swiss 3-pin)

SEV 1011 (Swiss 10 A/250 V) Switzerland has its own standard which is described in SEV 1011. (ASE1011/1959 SW10A-R) This plug is similar to the type C europlug (CEE 7/16), except that it has an earth pin off to one side. Swiss sockets can take Swiss plugs or europlugs (CEE 7/16). This connector system is rated for up to 10 amperes. There is also a less common variant with 3 square pins rated for 16 A. Above 16 A, equipment must either be wired permanently to the electrical supply system with appropriate branch circuit protection, or connected to the mains with an appropriate high power industrial connector.
   Switzerland also has a two-pin plug, with the same pin shape, size and spacing as the SEV 1011's live and neutral pins, but with a more flattened hexagonal form. It fits into both Swiss sockets (round and hexagonal) and CEE 7/16 sockets, and is rated for up to 10 A.

Type K (Danish 3-pin)

Section 107-2-D1 (Danish 10 A/250 V earthed) This Danish standard plug is described in the Danish Plug Equipment Section 107-2-D1 Standard sheet (SRAF1962/DB 16/87 DN10A-R). The plug is similar to the French type E except that it has an earthing pin instead of an earthing hole (and vice versa on the socket). This makes the Danish socket more unobtrusive than the French socket which is a cavity into the wall to protect the earthing pin from mechanical damage (and to protect from touching the live pins).
   The Danish socket will also accept the type C CEE 7/16 Europlug or type E/F CEE 7/17 Schuko-French hybrid plug. Type F CEE 7/4 (Schuko), type E/F CEE 7/7 (Schuko-French hybrid), and earthed type E French plugs will also fit into the socket but shouldn't be used for appliances that need earth contact. The current rating on both plugs is 10 A.
   A variation (standard DK 2-5a) of the Danish plug for use only on surge protected computer circuits exists. It fits into the corresponding computer socket and the normal type K socket, but normal type K plugs deliberately don't fit into the special computer socket.
   There is a variation for hospital equipment with a rectangular left pin, it's used for life support equipment.
   Traditionally all Danish sockets were equipped with a switch to prevent touching live pins when connecting/disconnecting the plug. Today, sockets without switch are allowed, but then it's a requirement that the sockets have a cavity to prevent touching the live pins. However, the shape of the plugs generally makes it difficult to touch the pins when connecting/disconnecting.
   Since the early 1990s grounded outlets have been required in all new electric installations in Denmark. Older outlets need not be grounded, but all outlets - including old installations - are required to be protected by RCD/GFCI (in Danish) no later than 1 July 2008.
   After 1 July 2008 Wall outlets for type E (French 2-pin, female earth) will be permitted for installations in Denmark.
   Sockets for the Schuko F type won't be permitted. The reason is that a large number of currently used Danish plugs will jam when inserted into a Schuko socket. This may cause damage to the socket. It may also result in a bad connection of the pins, which implies the risk of overheating and fire.

• Adapter plugs exist to allow connection of other plugs (British, American etc.) to Danish (non-computer) outlets. These usually are not sold at the local Danish supermarket so visitors wishing to be safe may contact an electrician. However, many international travel adapter sets sold outside Denmark match type C CEE 7/16 (Europlug) and type E/F CEE 7/7 (Schuko-French hybrid) plugs which can readily be used in Denmark as explained above.

Type L (Italian 3-pin)

CEI 23-16/VII (Italian 10 A/250 V) The 10 ampere style extends CEE 7/16 by adding a central earthing pin. Thus, CEI 23-16-VII 10 A sockets can accept CEE 7/16 Europlugs. This is the plug shown in the illustrations. Outside of Italy, this plug is found in Syria, Libya, Ethiopia, Chile, Argentina, Uruguay, various countries in North Africa, and occasionally in older buildings in Spain.

CEI 23-16/VII (Italian 16 A/250 V) The 16 ampere style looks like a bigger version of the 10 A style. The pins are a couple of millimetres further apart, and all three are slightly thicker. The packaging on these plugs in Italy may claim they're a "North European" type. They were also referred to as industriale ("industrial") although this isn't a correct definition.

Variations in sockets Two types of sockets are in common use in modern installations in Italy. One type has a central round hole and two 8-shaped holes above and below. This design allows the connection of both styles of type L plugs (CEI 23-16/VII 10 A and 16 A) and the type C CEE 7/16 Europlug. The advantage of this socket type is its small face.
   The other type looks like a type F socket, but adds a central grounding hole. This design accepts CEE 7/7 (type E/F) plugs, in addition to type C and type L 10 A plugs; its disadvantage is that it's twice as large as a normal type L socket. Some of these sockets also have extra holes to accept type L 16 A plugs. Another disadvantage of this kind of socket is the impossibility to accept most of the AC/DC wall-mounted power supplies without an adapter or an extension cord, because of its pit-shaped design.
   Older installations often have sockets that are limited to either the 10 A or the 16 A style plug, requiring the use of an adapter if the other style needs to be connected.

Type M (see D)

BS 546 (South African 15 A/250 V) Type M is sometimes used to describe the 15 A version of the old British type D, used in South Africa and elsewhere. See type D for details.

Multi standard sockets

Proposed common standard IEC 60906-1

IEC 60906-1 (Brazilian 16 A/250 V) In 1986, the International Electrotechnical Commission published IEC 60906-1, the specification for a plug that looks similar but isn't identical to the Swiss (Type J) plug. This plug was intended to become one day the common standard for all of Europe and other regions with 230 V mains but the effort to adopt it as a European Union standard was put on hold in the mid 1990s. Brazil — which uses a mix of Europlug and NEMA plugs — later adopted it as national standard NBR 14136 in 2001 and it'll be the only plug permitted to be sold with domestic appliances in Brazil from 2009.

Safety notes

Further Information

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