Home:  Subscriber Apparatus: GPO LINE INSULATORS AND WALL BRACKET, 1940's


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Fitted to walls, and can still be seen to this day, they were used by the Post Office Telephone Department, to suspend bare wires made of a mixture of Cadmium and Copper in exactly tested proportions to carry the weight of the telephone line over long distances. Before 'Drop Cabling' which was two wires insulated in Vulcanized Rubber, and underground Ducts were introduced in the early 1930's , all telephone lines were suspended airborne between poles and brackets similar to these.

Your comments:

  • These were called potheads in NZ. Invented by mssrs Purves and Sinnot in early 1900's according to one old textbook. The ones we used were Usually single groove and made of black composition (Telenduron?).
    We also used the 'Sinclair-Aitken' 2 piece insulators particularly for party lines. They also got used as teacups by the linemen.
    .......... Arthur Williams former NZPO lineman. Awarua Communications Museum , Invercargill New Zealand, 30th of September 2012

  • I still have one of these installed on my house, and is the only one I can see in my local neighbourhood.
    Do I still need it fitted?
    .......... David Linkson, Croydon, Surrey UK, 16th of September 2011

  • I have an unusual collection Ex GPO and GWR insulators, they are varied, during WW2 they were made of black composite material and can be still be seen around towns. This is a No 16, the No 3 was the most common, This No 16 was used for changing from open copper to a leading in cable. The large Alkinson insulator with the detachable centre, were used as tea cups by the overhead gangs.
    .......... C H Hughes , Bicester Oxon UK, 5th of December 2010

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