View Single Post
Old 14th Jan 2012, 3:12 am   #46
emeritus
Dekatron
 
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
Default Re: Another unusual plug and some other questions

The information on the "Wandsworth" sockets was most informative. They were used on the Becontree council estate in Essex until the houses were rewired in the 1960's. They were still being used in a Becontree barber's shop that I used to visit in the early 1970's. I always wondered why the earth pin was slotted!

Regarding the date of introduction of mains plugs, I have some GEC catalogues for 1893 and 1912.

The 1912 catalogue only lists 2 pin plugs for domestic use, "Midget" gauge at 3A [ apparently corresponding to the later 2A plugs] ; 5A "Standard" gauge that is still used as the UK shaver plug, 10A "Union" gauge, and "Goliath" gauge 25A. Mechanically robust plugs rated at 25A and 50A for use in theatres were also available. Also illustrated was a range of Concentric mains plugs that were essentially larger versions of the present coax TV plug interface. Apparently the Royal Navy used them. Switched sockets were not available.

A range of earthed connectors was available for industrial and naval use. Reference is made to a Board of Trade report of 1910 that discusses the properties of and defects of the earthed mains connectors then available which I am trying to track down [the IET library doesn't have a copy].

The 1893 catalogue lists 5A, 10A and 20A 2 pin plugs, with a choice of switched and unswitched sockets, together with the once-universal BC adaptor and its ES cousin. In addition, Coaxial plugs were available in 5A and 10A versions that were essentially larger versions of the present low voltage DC power plugs. The 2 pin plugs appear to have been available prior to 1893, but the coax plugs were new. GEC seemed to have been keen on promoting them as most of the illustrated electrical appliances of the 1893 catalogue are depicted fitted with the coax plugs.

It could be that the what is now the UK 2pin 5A shaver plug gauge can trace its origins back to at least 1893, making it a contender for the oldest mains plug gauge [other than lamp bases] that is still in use.
emeritus is offline