Museum of Plugs and Sockets logo, small Bulgin and Belling Lee
connectors
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For many decades British companies Bulgin and Belling Lee are producing series of small connectors for lower currents. There is a choice of configurations with 3 to 8 poles. For portable audio and lighting equipment both cable and chassis mounting versions exist for inlets, outlets and plugs.

The collection of classic connectors shown below has been donated to the museum by David Fisher. The material was used in the 1970s for building lighting and sound controllers and theatre use.
Similar versions of some types are still in production. Details are given in the captions below.

 

Bulgin

empty image Bulgin 5A 3-pin plug
Bulgin 5A 3pin outlet
Bulgin 5A 3-pin plug
       
Bulgin 5A 3-pin plug, angled Bulgin 5A 6-pin connector plug
Bulgin 2A 3-pin outlet
Bulgin 2A 3-pin plug

1, 2
Three pole, chassis mount inlet rated at 5A - 250V (image no. 1) and matching connector plug (image no. 2). The three contacts have a equilateral position, but a key ensures correct polarity. Pin diameter = 4.9 mm; pin length = 13.3 mm (L and N) and 13.8 (earth). Inlet and plug have screw terminals.
This model was commonly used to feed power into portable equipment. It is to be regarded as a precursor of IEC 60320 C13/14 connectors.
3, 4
5A - 250V chassis mount outlet (image no. 3) and corresponding plug (image no. 4). The outlet offers the possibility to feed related equipments, for example to connect a turntable to the audio amplifier. Instead of a key, correct polarity is ensured by the earth pin that has a larger diameter than L and N pins (respectively 5.6 and 4.8 mm). Pin length = 13.5 mm (E) and 11.9 mm (L and N). The longer earth pin and the more external position of the outlet earth contact ensures that earth contact is made first. Outlet and plug have screw terminals.
5 A 3-pole, 5A - 250V flex mount connector, with screw tags. Pole position is identical to nos. 1 and 3, but compared to plug no. 2 this angled connector has an 'inverted' type of key. This means that the connector fits in three - 60 degrees rotated - positions into inlet no. 1. Apparently connector no. 5 belongs to another series than nos. 1 and 2.
6 Six pole, 5A - 250V flex mount connector plug, with screw tags. Later, the six pole connectors have been replaced by eight pole models. According to the Bulgin website they are now the standard connector for disco and lighting industry.
7, 8
Three pole, 2A - 250V outlet (image no. 7) and matching connector plug (image no. 8). They have respectively solder buckets and tags. Note the key that is connected to the earth contact. The model is still (2015) in production, but now rated at 3A; see SA2402 (outlet) and SA2403 (connector) in the Bulgin product catalogue.

 

Bulgin 1.5A 3-pin plug Bulgin 1.5A 50V 3-pin plug and inlet
Bulgin 1.5A 50C 6-pin plug and inlet
50A MAX warning on Bulgin plug

9 1.5A - 250V 3-pole angled connector plug, with solder tags. See also caption to image no. 10.
10 1.5A - 50V 3-pole connector plug (left) and chassis mount inlet (right). The Bulgin 2015 catalogue shows that plugs and inlet comparable to each of the 1.5A, 3-pole models still exist, but now they are rated at 3A - 250V; see PX0430, PX0646 and PX0429.
11 Six pole, 1.5A - 50V connector (left) and chassis mount inlet (right). Comparable, modern models are PX0636 (plug) and PX0635 (inlet). They are rated at 3A - 50V.
12 Warning on the cord end of connector plugs shown in image nos 10 and 11. It is presumed that the 250V inaccessibility refers to the diameter of the cord entry (9.4 mm) and the absence of a cord grip.
note
Angled connector plugs (nos. 5, 8 and 9) have inspection ports for checking earth wire connection.

 

Belling Lee

Belling Lee 10A-250V inlet Belling Lee 10A-250V plug
Belling Lee 10A-250V plug
Belling Lee 10A-250V plug
       
Belling Lee 3A-250V inlet and plug
Bulgin and Belling Lee logos


13 - 15
Type L1722 3-pole chassis socket (image no. 13) and line plug (image no. 14), rated at 10A - 250V. Socket contacts are recessed and have solder or snap-on terminals. Plug pins are fully shrouded and have screw terminals.
Image no. 15 shows the inspection port to allow instant inspection of the earth wire connection.
The L, N and E contacts are positioned in a non-equilateral triangle to ensure correct polarity.
Belling Lee 10A power entry connectors are still available (2015).
16
The rear side of socket no. 13 shows a remarkable detail. There are two codes: L1722A/S and P.O.11A (green arrow). The first code is the connector type, whereby A/S refers to a fixed power connector (chassis socket), whereas the 'free' plug has code L1722/P. The second code relates to Post Office. Belling Lee L1722 connectors were frequently used to power in to portable Post Office equipment. PO is later renamed to BT = British Telecom.
17 Type L1436 3--pole line plug (left) and chassis socket (right), rated at 3A - 250V. Most characteristics are identical, to the 10A model. The images of 3A and 10A model have approximately the same scale. Although the 3A plug and socket are undoubtable Belling Lee designs, they have a RS, rather than Belling Lee logo (see image no. 18). RS Components Ltd mainly sells products made by other companies, but has its own RS label too. Apparently a link between Belling Lee and RS have existed, but Belling Lee products are no longer in the RS catalogue.
18 Each of the Bulgin products shown here carry the name BULGIN  MADE IN ENGLAND, or BULGIN ENGLAND.
The Belling Lee logo (bottom left) is shown on the 10A socket and plug. The 3A models have a RS mark (bottom right).
 
note
 
Additional information given by David Fisher:
" Virtually all of the Bulgin connectors were very brittle due to their construction material which was a form of black Bakelite, apart from outlet and plug nos. 3 and 4 which was a later version made of plastic*. The Bulgin line connectors would frequently break if they were dropped onto a hard surface and the rear part would usually shatter and need replacing.
The Belling Lee connectors were much more resilient to impact and would often make a better and more reliable connection especially when frequently plugged and unplugged."
* nowadays Bulgin connectors are made of a phenolic resin, comparable to material used by Belling Lee.

 


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