plugs and sockets
was a registered trademark of the company started out as George H.
Scholes Ltd (Manchester, UK). Wylex introduced in 1926 a three-pin plug
in three sizes, 5A, 10A and 15A. The two smaller plugs were fused.
After the introduction of BS 1363 in 1947 Wylex changed ratings to 2A,
5A and 13A. Plugs and sockets
have been used in both public buildings and homes, but only in parts of
Britain and never on a large scale. In the early years of computerization they
have been used in local circuits that provide for an uninterrupted
power supply without voltage spikes. Wylex plugs and sockets
gradually disappeared at the end of the last century, but the Wylex
brand name - now being a part of the Siemens Holding plc. - still exists for residential miniature circuit breakers.
The increasingly rare plugs and socket shown here have been donated by two enthusiastic visitors of the museum; see Acknowledgments.
Wylex plugs are shown here in full detail, since they are hardly known outside the UK. The same scale is used for image nos. 1-12.
|1||Wylex surface mount socket, rated at 3KW (13 Amps x 240 Volt = 3120 Watt, or 3KW). All Wylex plugs and sockets are polarized (see also no. 7). Live and neutral cannot be swapped when a plug is inserted. The 3 KW sockets shown is suitable for 13A, 5A and 2A plugs. Also the 5-15A dual plug (see image nos. 12-15) fits in this socket|
|2||Cover of a 3KW plug. Most covers of Wylex plugs clearly indicates the type. The plug has a BS 1362 13A fuse.|
|3||Pins of a 13A plug. The round earth pin is longer than the flat live and neutral pins (see table below). This safety feature ensures that earth makes first contact when plugged in.|
fused, dual, 13A plug. 'Dual' means that the top of the plug (not
shown) has an outlet for a 5A or 2A plug. This feature, known as
pick-a-back, is shown in more detail in images 12 - 15. The plug has a
13A BS 1362 fuse.
The straight side of the plug makes it easy to find the correct orientation for inserting the plug into a socket. Moreover, the externally accessible fuse compartment is a convenient addition. Both features suggest that the plug is a relatively modern variant.
|5||Wylex 5A plug. The diameter of 5A plugs is approximately 10% smaller than 13A plugs (47.5 mm / 1.87" versus 53.6 mm / 2.1").
|6||Live and neutral pins of a 5A plug are less wide than 13A pins (compare with no. 3; dimensions are given below). Round earth pins are identical. 5A plugs fit in 13A sockets since both plug variants have the same pin layout.|
|7||Each Wylex plug is polarized, because the live pin is off line with the neutral and earth pin; compare with socket no. 1. The image clearly shows that the round earth pin is (partly) hollow. The inner part makes contact with a short, recessed earth pin of the socket (just visible in image no. 1). The contact zone of the socket earth pin is approximately 6 mm long. The diameter is about 1.5 mm larger than the inner diameter of the plug earth pin. To ensure a firm earth contact the socket earth is somewhat flexible, because it has two, perpendicular, incisions over its full length.|
|8||Fused Wylex plugs are permitted for using in ring circuits. Plugs nos. 2-3, 4 (both 13A), 5-8 (5A) and 10-11 (2A) are fused.
13A plugs have a BS 1362 type of fuse, whereas 5A and 2A plugs have a smaller BS 646 fuse.
|9||Wylex 5A plug for special purposes with a vertical, rather than horizontal neutral pin. Not fused. Note that inner diameter of the hollow earth pin is smaller compared to standard plugs (dimensions are given in the table below). Orientation of the neutral pin and smaller inner diameter of the earth pin prevents the use of this plug in a standard Wylex socket (see no. 1).|
|10||Wylex 2A plug; top of cover.|
|11||Wylex 2A plug. The live and neutral pin are identical to 5A plugs. A 2A plug fits in a standard Wylex socket (see no. 1). However, the essentially round earth pin has two flat sides, which probably means that adapted sockets have existed for 2A plugs only.|
|12||A 5-15A dual plug; note that the image does not show the plug pins (see also no. 14). A pick-a-back, often shortened to piggyback plug is a more common name given to a combination of a plug (15A) and outlet. The width of the L and N slots restricts the outlet to 5A or 2A plugs. Not being fused (see no. 14) and a rating of 15A, are typical features of the original type of Wylex plugs (pre-1947.|
|13||Stack of 3 KW socket, 5-15A dual plug and 5A plug (could also have been a 2A plug).
|14||Partly dismantled dual plug together with a 5A plug. See also no. 15.|
|15||Both dual plug and 5A plug dismantled. The 5-15A dual plug is not fused, but 5A plugs have always been fused.
|Pin dimensions of Wylex plugs|
|width of flat
L, N pins
|length of flat
L, N pins
of round earth pin
of round earth pin
|length of round
|13A, fused||6.4 mm||18.8 mm||10.8 mm||7.2 mm||23.7 mm|
|5A, fused||4.8 mm 1||18.8 mm||10.8 mm||7.2 mm||23.7 mm|
|2A, fused||4.8 mm||18.8 mm||10.8 / 8.5 mm 3||7.2 mm||23.7 mm|
|5A special||4.8 mm||18.8 mm||10.8 mm||5.1 mm||23.7 mm|
|5-15 dual plug
| 8.0 mm 2
||10.8 / 7.9 mm 4
|1||The smaller pin size of 5A plugs compared to 13A points to the existence of sockets for 5A (and 2A) plugs only. See also the 5A outlet of the 5-15A dual plug (image no. 12).|
|2||The larger pin size of non-fused 15A plugs compared to fused 13A plugs suggests that resized sockets have been designed when ring circuit wiring was introduced, which required fused plugs. Non-fused plugs would not fit in the resized sockets.|
|3||The earth pin of 2A plugs has two flat sides, which locally reduces the diameter to 8.5 mm (see image no. 11). This adaptation suggests that sockets must have existed for 2A plugs only.|
|4||For unknown reasons the basal part of the earth pin of some 15A and 13A plugs have a smaller diameter than the top end. See for example the 5-15A dual plug (image no. 14). Other plugs have a white plastic collar around the basal part of the earth pin.|
|Click for information about Dorman & Smith, another competitor of the BS 1363 standard|