SN 441011, until 2019 SEV 1011,[1] is the Swiss national standard for AC power plug for domestic use and similar purposes. The plug SN 441011 Type 12 and the socket SN 441011 Type 13 are also known internationally as Type J, and fits in all Swiss sockets.[2]
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”.[3] 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).[4] 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[5] 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).
| Single phase, Live & Neutral | Single phase, Earthed, Live, & Neutral | Three-phase, Earthed, 3 × Live, & Neutral | Cross section of the contact pins | ||
|---|---|---|---|---|---|
| 2.5 A | π × 2² ≈ 12,57 mm² | ||||
| 10 A | Type 11 | Type 12 | Type 15 | π × 2² ≈ 12,57 mm² | |
| 16 A | Type 21 | Type 23 | Type 25 | 4 × 5 = 20 mm² |
The Swiss standard is described in SN 441011 "Plugs and sockets for household use and similar purposes",[6] which contains the following standard sheets:
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.
The 10 A series has been gradually standardized:
Then the 16 A variant (types 21, 23, 25) was introduced in 1997.
Originally, T12 plugs and sockets (the most common in domestic use) posed a safety concern. As the T12 sockets are flat and as the pins of the plugs did not have any insulation, the electrical contact was established in the pins even though the latter remained accessible, not fully inserted.
T13 sockets do not present this risk because they are recessed. When the electrical contact is made, the pins are fully within the recess and are therefore not accessible. T13 sockets were required in wet spaces (bathrooms, kitchens, etc.) and in many workplace environments.
The 2009 revision of the SEV 1011 standard therefore introduced two measures:
Measure 1 alone ensures electrical safety in new installations, but it does not improve the safety of existing installations. However, electrical outlets often remain in place for decades. Measure 2 then makes it possible to improve safety when using existing T12 sockets: when electrical contact is made in a partially insulated pin, the conductive part is no longer accessible, even with a non-recessed socket. Since electrical appliances are replaced comparatively often (more often than sockets), the situation should improve overall in a few years.