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3-phase plugs and sockets
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Denmark has a unique type of 16A three-phase plugs and sockets for domestic indoor use, known as the Dansk Flerpolet System (Danish Multipole System). They are already made for many decades by Lauritz Knudsen. IEC 60309 devices are used for (semi-) industrial and outdoor applications.


Danish 3-phase socket Danish 3-phase socket Danish 16A 3-phase plug Danish 3-phase socket and plug

Old Danish 1-phase socket comparable to 3-phase sockets Stots of Danish 3- and 1-phase sockets
Danish 3-phase connector plug Danish 16A 3-phase plug and connector

1, 2
Three-phase socket, rated at 16A - 400 V. The socket dates probably back to the 1990s. Model for surface mounting, either vertical or horizontal (under a kitchen or workshop bench). The recessed outlet is covered by a lid (see also image no. 4).
3 Three-phase plug, rated at 16A-440V. Three-phase plugs are irreversible because of the shape of the protective earth pin (center pin) and guides/notches at the right hand side of plugs/outlet (see nos. 2 and 6).
Socket no. 1 with a red/green* version of plug no. 3. Note that the lid has a 'hook' to prevent an untimely disconnection of the plug when a pulling force is exerted on the connected cable. Connector no. 7 has a comparable provision; see image no. 8.
5 Classic single phase socket with switch rated at 10A - 250V. The outlet resembles that of three-phase models (nos. 1 and 7). See images 6, 9 and 10 for details. This probably late 1930s model is obsolete now.
6 Comparison of the slots of three-phase socket no. 1,2 (top image) and classic single phase model no. 5. Sockets show the old abbreviations:  zero (neutral), F (phase = line) and J (jord, Danish for earth). Modern markings are copied from plug no. 3.
7, 8
Red/green* three-phase connector with lid, rated at 16A-440V. Image no. 8 shows plug no.4 inserted in connector no. 7.


Two-colored red/green plugs and sockets indicate hardened versions for use in rough (workshop etc.) conditions. They are made from a stronger plastic type but are otherwise identical to their regular domestic versions. Red/green plugs fit in standard sockets as image no. 4 shows.   Information given by Jacob Bohn, Denmark.

Danish single phase 16A socket, classic model Danish single phase 16A socket, classic model

9, 10

Inside view of the classic 10A single phase socket no. 5.

The enlarged image of the earth contact shows that one of six clips is missing (green arrow), because the earth pin has a guide for the correct orientation of the plug (see plug no. 3).

The socket has a two pole switch. Image no. 10 shows the mechanism that makes/breaks the neutral and line connection.


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