Mains electricity by country

Plugs

A plug is defined in IEC 60050 as an accessory having pins designed to engage with the contacts of a socket-outlet, also incorporating means for the electrical connection and mechanical retention of flexible cables or cords; a plug does not contain components which modify the electrical output from the electrical input (except where a switch and/or fuse is provided as a means of disconnecting the output from input). Informally, power conversion devices with incorporated plug pins may be also called "plugs", but IEC 60050 refers to these as 'direct plug-in equipment' defined as equipment in which the mains plug forms an integral part of the equipment enclosure so that the equipment is supported by the mains socket-outlet. In this article, the term 'plug' is used in the sense defined by IEC 60050.

The types used in each country are set by national standards, some of which are listed in the IEC technical report TR 60083, Plugs and socket-outlets for domestic and similar general use standardized in member countries of IEC.

The international standard IEC 60884-1 defines the general requirements for plugs and sockets intended for household and similar purposes, IEC 60884-1 does not define specific plug and socket types, which are the subject of national standards in each country. IEC 60884-1 para 9.2 does stipulate that: it shall not be possible, within a given system, to engage a plug with a socket-outlet having a higher voltage rating or a lower current rating. IEC 60884-1 para 6.1 defines the preferred voltage ratings for single phase plugs and sockets as 130 V or 250 V. In the foreword of IEC 60884-1 it states: in order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

The lettering system used here is from World Plugs, which defines the letter names and gives a (not always correct) list of what plug types are used where. Type A makes specific reference to American and Japanese plugs, as does Type B, which is specifically rated at 15 A. Type C is specifically identified as the Europlug (which is defined in EN 50075) and described as a plug which fits into any socket that accepts 4.0–4.8 mm round contacts on 19 mm centres. Type D is specifically rated at 5 A. Type E (grounding pin in socket) and Type F (grounding clips on both sides) are specifically rated at 16 A and defined as having 4.8 mm pins on 19 mm centres. Type G is identified as the fused British plug. The Type H plug is described as unique to Israel. Type I (Australian) is described as having both 10 A and 15 A ratings. Type J (Swiss) is rated at 10 A and is differentiated from Type N. The Type K rating is not shown. The Type L (Italian) description includes both ratings and pin sizes. Type M is described as looking similar to Type D, but with much larger pins. The Type N description is of the two variations of Brazilian plug (Brazilian national standard NBR 14136); however, the original plug and socket is defined in IEC 60906-1 and has been adopted as a South African national Standard (SANS 164-2). The Brazilian version is non-compliant with the IEC standard. Not all plugs are included in the letter system; for example, there is no designation for the plug defined by the Thai National Standard TIS116-2549.

IEC World Plugs is ambiguous in some areas: it does not reference national technical standards that define the dimensions and tolerances of devices. Plugs will usually mate with sockets which are intended to accept plugs classified under the same letter type, but there is no guarantee of this. There is also an issue relating to Type C, the EN 50075 Europlug, which has no dedicated socket in the standard and is designed to fit sockets accepting "4.0–4.8 mm round contacts on 19 mm centres", implying that there must be usage of such sockets in the territories listed as using Type C plugs. Despite this, World Plugs lists seven territories as using only Type C (i.e., no mention of specific plug types whose mating sockets also accept Type C) and twenty-one territories using Type C with no compatible types. This may be for a number of reasons, for instance the Thai standard TIS 166-2549 includes a socket which will also accept Types A, B and C plugs as well as the Thai plug (which does not have an IEC classification letter). Another possible reason is the use of so-called "universal sockets" in use in some countries; these accept multiple plug types but meet no standards and are not classified by the IEC.

The United States Department of Commerce published an earlier guide, which is now obsolescent and which has known inaccuracies. (See History of similar guides section below.)

Multi-standard sockets and adapters

Multi-standard sockets are sometimes used in China and some other Asian countries; these are intended to accommodate plugs conforming to various different standards. They do not normally have earthing (grounding) connections for either CEE 7/4 "Schuko", or CEE 7/5 (French), or their combination CEE 7/7. In multi-standard sockets, the aperture size for NEMA plugs is often the same for both Line (Hot) and Neutral, which allows a polarized plug to be inserted in either orientation, thus defeating the safety feature. Also, in a socket designed to accept both NEMA and BS 1363 plugs, the polarization can only be correct for one type of plug, so only appliances which do not require specific polarization should be connected. Multi-standard sockets made by Lengon are amongst those classified as serious safety risks, because they allow the user to come into contact with live parts.

Adapters that allow insertion of otherwise mechanically incompatible plugs into sockets are useful for travellers, but, as with multi-standard sockets, may not ensure the grounding and polarization intended by a compatible system of plugs and sockets.

Voltage rating of plugs and power cords

Plugs and power cords have a rated voltage (V) and rated current (A) assigned to them by the manufacturer, and these values are required to be marked on the plug. For a plug, the values are normally those specified in the relevant standard sheet. The international preferred rating for household plugs and sockets is either 130 V or 250 V; these are the values for normal use, and at which they are tested. (Plugs and power cords are also required to be tested at higher voltage for a brief period of 1 minute to test their electrical strength in case of fault conditions.) The NEMA 1–15 U.S. 2 pin (Type A) and NEMA 5–15 U.S. 3 pin (Type B) plugs are rated at 125 V. Similar plugs used in countries with higher mains voltages in the range 220–250 V are rated at 250 V. Using an appliance, plug or power cord which is not appropriate for the territory (e.g. one rated for 125 V with a 230 V supply) may constitute a safety hazard.

Type A and Type B sockets at greater than 125 V

Sockets connected to mains voltages above 125 V and which accept Type A or B plugs may be suitable for chargers and power supplies incorporating Type A pins, providing they have a suitable voltage rating.

Differences in standards for those plugs classified as Type I

Type I plugs also have differences in characteristics such as pin length. This means that the uninsulated pins of a Chinese plug may become live while there is still a large enough gap between the faces of the plug and socket to allow a finger to touch the pin. Argentinean connectors have the opposite polarity to those of other Type I countries.

Shaver sockets

National wiring regulations sometimes prohibit the use of sockets within certain areas adjacent to water taps etc. In such cases shaver supply units meeting IEC 61558-2-5 may be permissible. These include an isolation transformer and usually accept multiple two-pin plug types including Europlug (Type C), Australian (Type I) and BS 4573. The isolation transformer often includes a 115 V output accepting two-pin US plugs (Type A). Shaver supply units must also be current limited, IEC 61558-2-5 specifies a minimum rating of 20 VA and maximum of 50 VA. IEC 61558-2-5 requires sockets to be marked with the shaver symbol defined in IEC 60417-5225, the words "shavers only" are also often used but not required. IEC 61558-2-5 has been adopted as a European CENELEC standard EN 61558-2-5 and also as a national standard in some countries, e.g. UK (BS EN 61558-2-5) and Malaysia (MS IEC 61558-2-5).

Voltages

Voltages in this article are the nominal single-phase supply voltages. Three-phase and industrial loads will have other voltages.

All voltages are root mean square voltage; the peak AC voltage is greater by a factor of √2, and the peak-to-peak voltage greater by a factor of 2√2.

History of similar guides

In 1948 the US Government Printing Office published World electric current characteristics. This contained information on voltages used in the cities of many countries, but no information on plugs. The guide was republished by the US Department of commerce in 1954 as Electric Current Abroad. This was updated from time to time and the 1967 version includes some information on plugs, however only 3 types were designated: Type A, illustrated by a US style 2 pin plug, Type B, illustrated by a sketch of a BS 546 type, and Type C, illustrated by a sketch of a BS 1363 type. The 1984 edition uses the letters A to G in the same manner as they are used today. The last printed edition (listing plugs from A to H) was that of 1998, reprinted in 2002, it includes brief textual descriptions of each type illustrated by a sketch, only Type F (described as a Schuko) is specifically linked to a generally recognized type. The International Trade Administration of the US Department of Commerce now publishes a web version: Electric Current Worldwide, which still does not include the full list of plug types; it does not describe Type M or type N. There are sketches and photographs of each type, but no textual description or references to actual standards. Examples of errors in the website include the failure to mention that Brazil uses Type N, although that has been the national standard in that country since 1998; stating that the UK uses type C, which is not permitted there; and claiming that China uses Type H (the Israeli plug) when the main Chinese plug is actually type I.

There are many web sites from unofficial sources which also purport to offer lists of voltages and plug types.

Table of mains voltages and frequencies

Except where other sources are indicated, the plug type, voltage and frequency in this table are sourced from an official web page of the IEC:World Plugs

Entries in the plug standard column refer to the national standards pertaining to the relevant territory, and unless otherwise stated are sourced from IEC Technical Report 60083.