Museum of Plugs and Sockets logo, small Classic Danish
plugs and sockets
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Examples of Danish sockets and plugs, made in the 1930s - 1980s, are shown here.
Information about the Danish companies Lauritz Knudsen (LK) and Nordisk Elektricitets Selskab (NES) is given below.

On older Danish sockets Line, Neutral and Earth are indicated respectively as P or F (phase/fase),
0 (nul) and J (jord).

 

Danish classic  socket with push button switch
Danish classic  socket with rotary switch
Danish double, Bakelite, unearthed socket made Danish classic switched, watertight socket



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NES unearthed, double socket with switches LK single, unearthed socket with switch and control light
LK switched waterproof socket, details

1 Bakelite socket with press button switch (shown in off position). Socket is not earthed. The additional hole can accommodate an earth pin, but there is no corresponding earth contact. Rating: 6A - 250V. Manufacturer: NES. Dating: 1930s.   {PMR}
2 Bakelite, earthed socket with rotary switch. Rating: 6A - 250V. Manufacturer: NES. Dating: 1930s.   {PMR}
3 Bakelite, double, not earthed socket with separate tumble switches for each outlet. Rating: 6A - 250V.
Manufacturer: LK.
Dating: 1950s.   {PMR}
4a, 4b
Wall socket that can be used in wet conditions. Rating 6A - 250V. As image 4b shows it has a standard tumble switch, similar to socket no. 15. The sealed top cover has a kind of lever to turn the tumble switch from off to on, vice versa. The cover has a closed cavity that can accommodate an earth pin, but there is no earth contact inside. Manufacturer: LK. Dating: 1950s.   {PMR}
5 Double, not earthed socket. Outlets are controlled by press switches. The red bar indicates that the corresponding outlet is switched on. Manufacturer: NES. Dating: 1960s.   {PMR}
6 Single, not earthed socket with switch and control light. Internally, switch, light and outlet are not connected to each other. Each component can be wired separately. It depends on the wiring whether switch and light are controlling outlet or another device elsewhere. Manufacturer: LK. Dating: 1960s - 70s.   {PMR}

LK  unearthed socket with tumble switches LK-NES double, unearthed socket with switches D.A.F. Bakelite, not earthed plug and connector Classic Danish plugs made by HM and B&H

Danish classsic multi-plug
Danish lamp socket, classic model
Danish lamp socket, classic model
Danish lamp plug, classic model

7 Double, not earthed socket with switches. Switches are connected to the top contacts, indicated with P (phase). Rating: 10A - 250V. It is not possible to insert a plug in horizontal position, because the distance between left and right outlet is 4.5 mm larger than the 19 mm spacing between P (L) and 0 (N) pole. This applies also to socket nos. 3, 5 and 8.
Manufacturer: LK
. Dating: 1960s - '70s.   {PMR}
8 Unearthed, double socket, rated at 10A - 250V. Each outlet has its own switch. Switches are connected to the top contacts.
Manufacturer: LK-NES. Dating: 1970s - '80s.   {PMR}
9 Bakelite, 2-pin plug and connector, rated at 6A - 250V. Pin diameter: 4.0 mm.
Manufacturer: Dansk Køleautomatik og Apparat Fabrik - better known as Danfoss - fouded in Nordborg in 1933.
For a while electrical appliances have been made under the trademark D.A.F. (Dansk Apparat Fabrik). Dating: 1950s. Plug: {WN};  connector {PMR}
10 Two-pin plugs, rated at 6A - 250V. Pin diameter: 4.0 mm. Manufacturers: left: unknown company that uses trademark HM; right: B&H stands for Bruhn & Hansen who started production of electrical accessories in 1920 in Copenhagen. In the 1950s the company was renamed to B&H el-artikler and in 2010 to Elworks A/S and is now based in Fredrikshavn, Denmark
Dating of both plugs: 1970s - '80s.   HM plug {PMR},  B&H plug {DH}
11 Dual multi-plug, rated at 6A -250V. It has a Danish certification mark and logo of an unknown company that used initials B&N. The same initials have also been used by the Danish porcelain tableware makers Bucka & NIssen. Although links between porcelain manufacturers and makers of electrical accessories have existed - for example Legrand Limoges (France) - an indication for a comparable link with Bucka & Nissen has not been found. Dating: possibly 1950s.   {PMR}
12 - 14
Lamp socket and plug. Rating: 6A - 250/380V. Plug pins have a hole that helps to keep the plug in a fully inserted position. Lamp sockets have three pin contacts, indicated as 0, M1 and M2. 0 = neutral, M = line, beyond the light switch (M means mellemledning = wire between switch and lamp). Because of plug shape, change of M and 0 pin position is not possible. The maximum load of socket and hook construction is 7.5 kg. Manufacturers: NES as well as LK.   {PMR}

The classic model has probably been produced in the 1950s-'60s.
After that lamp sockets with straight pin plugs have been replaced by models with twist lock plugs (see Danish special plugs and sockets). A much older model consisted of a one piece porcelain ceiling plate with hook. It had fixed wire connections, rather than a separate plug.

empty image Classic, Bakelite LK hospital type plugs
NES, classic hostital type socket with switch

15 Bakelite earthed socket, for special purposes. This late 1930s model has slots for plugs with two flat power pins arranged in tandem position, see image no. 10a. Rating: 6A-250V. Manufacturer: LK.
16 Two Bakelite plugs, rated at 6A-250V, that date back to late 1930s. Plug 16a has flat Line and Neutral pins, whereas plug 16b has a flat Line pin and a round Neutral pin. Type 16b is identical to nowadays used hospital-specific plugs. Image no. 17 shows a matching socket.
Type 16a must have been designed also for special purposes, as alternative to the hospital type no. 16b. Image no. 15 shows the matching socket. Production of plugs with flat pins for both L and N and corresponding sockets have stopped decades ago.
Manufacturer: LK.
17 Hospital socket made by Nordisk Elektricitets Selskab. NES type T, standard and hospital type sockets were introduced in 1959. Rating: 10A-250V. Note the earth contact that consists of a single, brass strip, rather than a ring (compare with socket nos. 15). It seems that brass strips were a distinctive characteristic of NES sockets. A red bar is visible when the socket is switched on, comparable to socket no. 5.   {PMR}

Bender & Wirth adapter for E27 lamp socket
18
Porcelain adapter with 27 mm Edison light bulb screw base and two outlets for not earthed plugs with 4.0 mm pins. A model that has been used in many continental European countries. Given the Demko (D) certification mark, the adapter was made for the Danish market by Bender & Wirth in Kierspe-Bahnhof (Westfalen, Gemany). Dating: 1930s.   {PMR}

 

Logos of Lauritz Knudsen and NES



Logos of Danish companies B&H, B&N, DAF
Logos of Danish companies.  Top row:
  left: old Lauritz Knudsen logo, used up to 1960s;
  middle: logo used after merging of LK and NES in 1968;
  right: modern logo of LK.
Logos on second row:
  left: logo of
NES (Nordisk Elektricitets Selskab)
  right: logo that has some resemblance to Lauritz Knudsen, but it is an older logo
     of the German company Leopold Kostal in Lüdenscheid, found on 1930s plugs.
     The company still exists, but their logo has been updated.

Lauritz Knudsen Mechaniske Etablissement started in 1893 with design and production of electrical fittings, and became the leading Danish manufacturer of all sort of electric appliances. In 1968 LK merged with
NES (see below). In 1995 LK-NES merged with the Finnish group Ahlstrøm and became Lexel A/S. This company was taken over by the French company Schneider Electric in 1999. Laurtiz Knudsen is now incorporated in Schneider Electric Denmark A/S. The name LK is still used as brand name for Danish plugs, sockets, wiring material etc.

The Nordisk Elektricitets Selskab was founded in 1908 by Jensen and Jacobsen. It became the largest competitor of LK.
The NES factory in Valby was closed in 1976, eight years after merging with LK.

Logos on third row:  B&H, see plug 10;   B&N, see plug 11;   D.A.F. see plug 9

 


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