SN 441011

SN 441011, overview of the hierarchical Swiss System

The plug-in system defined in the standard for 250 V / 440 V alternating voltage at 50 Hz is structured to be “hierarchically downward compatible”.[2] This means that sockets designed for 16 amps also accept plugs for 10 amps, but not the other way around, and that 2- or 3-pole (single-phase) plugs can also be used with 5-pole (three-phase) sockets. The Euro plug (2.5 A) also fits into all 4 socket types.

In all versions with three or five contact pins (Types 12/13, 15, 23 and 25) the middle pole is the protective contact. Although the contact pins are of the same length, the protective contact is in advance because the sockets for the neutral conductor and phase conductor(s) are sunk deeper in the socket. The offset arrangement of the contacts ensures reverse polarity protection (with a socket, the phase conductor is on the right and the protective conductor is at the bottom).[3] All new sockets are equipped with protective collars. Sockets without protective collars were allowed outside of wet rooms until 2016, but existing sockets of this type can continue to be operated.

The Swiss standard was first described in SEV 1011 (ASE1011/1959 SW10A-R). On 4 December 2009, the TK23 Technical Committee issued the new revised edition of the Swiss standard SEV 1011:2009 for 10-A plugs and 11/12 sockets to provide, among other things, improved protection against contact with partially insulated pins can. As of 1 January 2013, imports into Switzerland of Type 11 and Type 12 plugs are only permitted with partially insulated plug pins. After the year 2016, only sockets type 13 with a recessed socket hole may be brought onto the market.

From the Type 12 proposed in 1937[4] and introduced in 1953, the international standard IEC 60906-1 was derived in 1986, on which only the national standards of Brazil (NBR 14136 or Type N) and South Africa (SANS 164-2) are based. Despite the great similarity, these are not compatible with SN 441011, as the polarity has been reversed in IEC 60906-1 and the earthing contact is only 3 mm offset from the center line instead of 5 mm. (A combined socket, which accepts both plugs according to SN 441011 and IEC 60906-1, would, however, be easy to implement, since a further hole for the earthing contact with the smaller distance would only have to be added opposite the previous central hole.) The hexagonal shape of the Euro plug (2.5 A) is also derived from the Swiss standard. This differs only slightly from the connector Type 11 (10 A).

The Swiss standard is described in SN 441011 "Plugs and sockets for household use and similar purposes",[5] which contains the following standard sheets:

• SN 441011-1: Description of the systems with risk analysis and national deviations from the IEC 60884 series
• SN 441011-2-1: Standard sheets and construction specifications for plug-in devices with degrees of protection IP20 and IP55
• SN 441011-2-2: Multiple and intermediate adapters, extension cables, socket strips as well as travel and fixed adapters
• SN 441011-2-3: Advices

Products according to the outdated standard SEV 1011:2009 may only be manufactured or imported until February 28, 2022.

Until 2019, SEV 1011:2009 (ASE1011 / 1959 SW10A-R) was the relevant standard.

On December 4, 2009, the technical committee TK23 published the new, revised edition of the then standard SEV 1011:2009 for 10 A plugs and sockets of type 11/12 in order to offer, among other things, improved protection against contact with partially insulated connector pins can.

From January 1, 2013, the import of Type 11 and Type 12 plugs into Switzerland will only be permitted with partially insulated pins. After 2016, only Type 13 sockets with a recessed socket hole may be brought onto the market.

Dimensions of the protective collar for sockets

Collars of sockets according to T11 and T21 are at least 16 mm (+1 mm) wide, those according to T13 and T23 at least 21 mm (+2 mm) wide. All collars of these types are at least 36.5 mm long. The respective angles are 45 degrees. Those of three-phase sockets have a dimension of 37.2 (± 0.7) × 39.5 (± 1) mm.

Protective collar depth for sockets

With single-phase sockets (T11, T13, T21, T23) the protective collar is 13 mm (+5 mm) deep, with three-phase sockets 17.5 mm (+1 mm) deep.

Dimensions of the connector

Plugs according to T11 and T21 are between 13 mm and 14.5 mm wide, those according to T13 and T23 between 14.5 mm and 20 mm wide. Connector according to T1 and T13 between 35 mm and 36 mm long. The respective angles are 45 degrees. Three-phase plugs have a dimension of 35.4 (± 0.7) × 30 (± 0.7) mm.

Pin length of the connector

The pins are 19 mm (± 0.5 mm) long on all types. The length of the insulation on the connector pins is 8 mm (± 0.25 mm).

Diameter of the pins and the openings

The pins of the 10 A connector are 4 mm (± 0.06 mm) in diameter. The diameter of the openings in the sockets is 4.5 mm (+0.2 mm). The pins of the 16 A plugs are 4 (± 0.06) x 5 (± 0.06) mm wide, the corresponding openings are 4.5 (+0.2) x 5.5 (+0.2) mm wide.

Distance between conductors

In both the 10 A and 16 A versions, the distance between the phase conductor and the neutral conductor is 19 mm (± 0.15 mm). The protective conductor is offset by 5 mm (± 0.1 mm). In the three-phase plugs and sockets (T15 and T25), L2 and L3 are offset by 8 mm (± 0.1 mm) from the protective conductor, i.e. the distance between L1 and L2 or between N and L3 is 13 mm.

• Europlug
• AC power plugs and sockets
• IEC 60906-1 derived from SN 441011 Type 12/13