IEC 60906-1

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IEC 60906-1 is the international standard 230 V household plug system. It was intended to become the common mains plug and socket standard, to be used one day everywhere in Europe and other regions with 230 V mains. The standard was published by the International Electrotechnical Commission in 1986. So far, only Brazil has plans to introduce it [link]. Although it looks similar to the Swiss plug, its dimensions are different.

This article is only about part one of this standard. 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.

Contents

1 Features
2 Comparison with traditional systems

2.1 BS 1363
2.2 Schuko

3 Dimensions
4 Differences to Swiss plug
5 Class 0 plug and socket
6 See also
7 References
8 External links

Features

The IEC 60906-1 system is rated for AC voltages up to 250 V and currents up to 16 A. It defines both 3-pin connectors for Class I appliances and 2-pin versions for Class II appliances.

The plug

has round (cylindrical) live and neutral pins, which are 19 mm apart and 4.5 mm in diameter (similar to the Schuko plug);
has an insulating sleeve around the base of the live and neutral pin (similar to the Europlug);
is smaller than any other European 3-pin plug, and only slightly larger than the 2-pin 2.5 A Europlug.

The socket

has either a 10 mm deep recess or a 12 mm high rim, to ensure that no commonly used plug can be inserted in a way that establishes contact to one pin while leaving the other pin exposed;
ensures that the protective-earth pin establishes contact before the live and neutral pins;
can be equipped with a child-safety shutter for the live and neutral contacts (similar to BS 1363 sockets);
is compatible with the Europlug;
is compact enough to permit the installation of two sockets in the space needed by a single Schuko or BS 1363 socket.

For most existing Continental 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 explicitely discourages the use of multi-standard sockets, claiming that such sockets are likely to create safety problems when used with plugs from other countries.

Comparison with traditional systems

Thanks to modern injection-molding technology, robust and safe plugs can have much smaller dimensions today than what was considered feasible when the old Schuko and BS 1363 systems were designed in the early and mid 20th century.

BS 1363

The IEC 60906-1 system features many of the advantages of the BS 1363 plug, but avoids the main problems with the system currently used in Britain and many Commonwealth countries:

incompatibility with the ubiquitous Europlug; (though this could easilly be changed if wiring regulations were changed to make it safe to do so)
lack of a practical way to design a migration socket that also accommodates the Schuko system;
large size;
risk of foot injury through a plug shape that makes it likely that the sharp pins face upwards when a plug lies on the floor.

However, unlike with BS 1363, 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, and to introduce national variants of IEC 60906-1 that mandate fuses. However, the mere fact that the same plug might be used without fuses in other regions would require additional precautions should this system ever replace BS 1363 in Britain, such as the use of fuses in sockets or stricter safety requirements for power cords. 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.)

Schuko

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 live and neutral (which made no difference in the IT earthing systems in use when Schuko was invented in the 1920s, but which prevents in modern TN earthing systems occasionally possible minor safety, electromagnetic-compatibility, and cost improvements);
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.

Dimensions

The plug's shape is similar to the Europlug; its front profile is also a flat hexagon, but it is slightly thicker. It is 35.5 mm wide and 17 mm high. The parallel side faces are 26 mm apart, and the two pairs of side faces are orthogonal to each other. In addition to the live and neutral pin, which have the same dimensions as the Schuko plug, the 3-pin version has also a round protective-earth pin. It has the same length and diameter as the live and neutral pins, but has no insulating sleeve around its base. The protective-earth pin's center is offset 3 mm from the center point between the live and neutral pin.

Differences to Swiss plug

Although the Swiss plug looks remarkably similar to the IEC 60906-1 plug, there are a number of significant differences. The Swiss SEV 1011 plug

has the earth pin further away from the center line (5 mm instead of 3 mm)
has slightly thinner pins (4 mm instead of 4.5 mm)
lacks insulating sleeves around the live and neutral pins
is only rated for 10 A

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:

fits into Plug
Class 0
(2 pin) Class I
(3 pin) Class II
(2 pin)
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

fits into	Plug
Class 0 (2 pin)	Class I (3 pin)	Class II (2 pin)
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.

References

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., International Electrotechnical Commission, 1986.

Brazilian Standard NBR 14136, July 2001.

External links

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