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IEC 60906-1 is an international standard for 230 V AC domestic power plugs and sockets. It was conceived as a common mains plug and socket standard for use in territories with 230 V mains.The standard was originally published by the International Electrotechnical Commission in 1986. Although it looks similar to the Swiss SEV 1011 plug, its dimensions are different. So far, only South Africa has introduced a standard (SANS 164-2) based closely on IEC-60906-1. Brazil used it as the starting point for its NBR 14136 standard, but this does not conform to IEC-60906-1.
This article is only about part one of IEC 60906. Part two, IEC 60906-2, defines a global standard plug for 115 V mains. It is compatible with the systems used today in North America and Japan. Part three, IEC 60906-3, defines a family of extra low voltage connectors.
IEC 60906-1 plugs and socket-outlets are rated 16 A, 250 V a.c. and are intended for use on distribution systems having nominal voltages between 200 V and 250 V a.c. IEC 60906-1 defines both 3-pin connectors for Class I appliances and 2-pin versions for Class II appliances.
The plug has 4.5 mm round pins, line and neutral are 19 mm apart with insulating sleeves. It is smaller than current European plugs with the same current rating.
The socket has either a 10 mm deep recess or a 12 mm high rim, to exclude incompatible plugs. It ensures that the protective-earth pin establishes contact before the line and neutral pins. The socket must have shutters for the line and neutral sockets, and is small enough that two can be installed in the space taken by a single Schuko or BS 1363 socket.
For most existing European systems (Schuko, etc.), it would be possible to design sockets that can accept both the traditional plug as well as the IEC 60906-1 Class I and II plugs, thereby enabling a smooth transition to the new system. However, the IEC 60906-1 standard explicitly discourages the use of multi-standard sockets, claiming that such sockets are likely to create safety problems when used with plugs from other countries.
Brazilian NBR 14136 standard
Brazil uses both 127 V and 220 V mains supplies, but rather than using the IEC 60906-2 standard for the lower voltage it uses NBR 14136 for both. Whereas IEC 60906-1 specifies a single 16 A rating with 4.5 mm pins, NBR 14136 has both 10 A and 20 A ratings, the 10 A plug has a pin diameter of 4 mm, and the 20 A plug is 4.8 mm. The 10 A socket will accept only 10 A plugs, and Europlugs, while the 20 A socket will accept both 10 A and 20 A plugs, plus Europlugs.
Comparison with traditional systems
Thanks to modern injection moulding technology, robust and safe plugs can be smaller today than was considered feasible when the old Schuko and BS 1363 systems were designed in the early and mid 20th century.
The IEC 60906-1 system features many of the advantages of the BS 1363 plug, but avoids the problem of incompatibility with the Europlug. It is smaller than a BS 1363 plug, and is rated for 16 amperes instead of 13. The flat design avoids the risk of stepping on upward-facing pins.
However, IEC 60906 does not mandate a fuse in each plug. It may well be feasible to design IEC 60906-1 plugs with an integrated fuse. Handing over the protection measures to sockets would violate British wiring rules because each plug is hardwired to its power cord and each power cord, depending on wire thickness, requires an appropriate fuse. The socket can not have a universal fuse which would match the power cord's current capacity of each appliance. The other way to meet British wiring rules is to use power cord for 16 Amps (maximum for IEC 60906-1) regardless of device power rating (which would be wasteful of copper and make cords on small appliances unnecessarily bulky and heavy). Also the plug is unlikely to have as low a profile to the wall, making use behind cupboards harder. (It is technically possible to make an IEC 60906-1 plug/socket combination with a similar profile to a BS 1363, but only if the socket has a recess and the cord exit angle exceeds the recommendations of the specification.)
The IEC 60906-1 system also avoids the problems of the Schuko system currently used in most of Europe and large parts of Asia:
- Ambiguity between line and neutral (On the side earth version).
- Lack of a practical way to design a migration socket that also accommodates the BS 1363 system;
- Large size;
- Mateability of Class I plugs with commonly used (non-Schuko) sockets that lack protective-earth contacts.
Although the IEC 60906-1 plug looks remarkably similar to the Swiss SEV 1011 plug, with a few differences. The Swiss plug has smaller pins with more spacing of the third pin.
The Class I and II plugs' shapes are similar to the Europlug; their front profile is also a flat hexagon, but it is slightly thicker. Both plugs are 35.5 mm wide. The 3-pin Class I plug is 17 mm high, whereas the 2-pin Class II plug is with only 14 mm slightly slimmer (the Europlug is only 0.3 mm smaller). The parallel side faces are 26 mm apart, and the two pairs of side faces are orthogonal to each other. As on the Schuko plug, the line and neutral pin have 19 mm center distance and 19 mm length. However, their diameter is 4.5 mm, unlike the Schuko plug, which has 4.8 mm pin diameter. In common with the Schuko plug and Europlug there is an insulating sleeve around the base of the line and neutral pins. The 3-pin version also has a round protective-earth pin. It has the same length and diameter as the line and neutral pins, but lacks an insulating sleeve. The protective-earth pin's center is offset 3 mm from the center point between the line and neutral pin.
Class 0 plug and socket
In addition to the hexagonal Class I and Class II plugs and sockets, Appendix A of the standard also defines a 2-pin plug and socket with oval profile, for countries that still permit the use of Class 0 appliances, which are considered unsafe in most industrialized countries today. The Class II plug fits also into Class 0 sockets; it is up to national regulations of countries using the Class 0 socket, whether they permit an additional dummy hole in it, such that even Class I plugs will fit. However, none of the Class 0 plugs fit into a Class I or Class II socket. This way, the system prevents that Class 0 equipment can be operated easily in regions that do not permit such devices. The full mateability matrix of all plugs and sockets defined in IEC 60906-1 looks like this:
|Socket||Class 0 (3 hole)||Yes||Yes||Yes|
|Class 0 (2 hole)||Yes||No||Yes|
|Class I (3 hole)||No||Yes||Yes|
|Class II (2 hole)||No||No||Yes|
As a result of the increasing global harmonization of electrical safety standards, IEC is phasing out the entire concept of Class 0 appliances from its standards. It is therefore unlikely that the oval Class 0 plug and socket variant will ever be introduced anywhere. The appendix that introduces it was probably merely added to address the concern that a system of country-independent plugs and sockets could permit the easy use of imported Class 0 equipment that does not meet national safety standards.
- AC: Alternating Current
- V: Volts
- IEC 60906-1 IEC system of plugs and socket-outlets for household and similar purposes - Part 1: Plugs and socket-outlets 16 A 250 V a.c. (PDF download requires payment of 66 Swiss Francs.), webstore.iec.ch
- Brazilian Standard NBR 14136, July 2001.
- South African Standard SANS 164-2:2006.
- International standardization of electrical plugs and sockets for domestic use, iec.ch
- South African Plugs and Sockets Standards
- Crabtree, a South African plug/socket manufacturer, started marketing IEC 906-1 connectors as slimline alternatives, crabtree.co.za