I mentioned in another thread I had the details of where our plug & socket configuration came from. I've since OCR'ed the article which was printed in "Australian Amateur Radio Action" vol 9, issue 12 (March 1987). Here it is:

"Unless they've been overseas, or stayed in an international-standard hotel, the majority of Australians probably take the ordinary 3-pin electricity mains plug and socket for granted. But anyone who has encountered the various non-interchangeable types of 2-pin and 3-pin plugs and sockets in use in Europe, the UK and the USA will be aware of Australia's good fortune in having a standard design throughout the country.
Shortly after World War 2, in about 1949, the UK adopted a 13A parallel flat pin design which incorporates a fuse in the plug, but Australia had adopted its standard long before this. Tracing its history, however, was more difficult than I had expected and involved me in some correspondence.
My first letter, to the Energy Authority of New South Wales, produced the information that "existing Authority records do not include the history of the origin of the standard three-pin, flat pin plug and plug socket. Plug and plug sockets used in this country comply with the requirements of Australian Standard AS-3 112-1981 'Approval and Test Specification for Plugs and Plug Sockets'as published by the Standards Association of Australia. This standard was first published in 1937 as AS-Cl 12 and the Standards Association of Australia may have a copy of the original issue plus each subsequent revised edition in its library at Standards House, 80 Arthur Street, North Sydney 2060.
'A measure of control over the sale of certain 'prescribed' and 'proclaimed' electrical articles and fittings, including plugs and plug sockets, has been exercised in New South Wales since 1938. The initial scheme in 1938 operated under the provisions of the Local Government Act 1919 and the present scheme operates under the provisions of the Electricity Development Act 1945.
"Plugs and plug sockets are 'prescribed articles' pursuant to the Electricity Development Act 1945 and, as
such, may not be sold, hired or exposed or advertised for sale or hire unless they have been approved by the Authority or the approving authority in another State and are marked with the allotted approvals marking. Similar legislation applies on each Australian State or Territory
"The approval marking takes the form of a letter identifying the State of origin approval, eg 'N' for NSW, 'V' for Victoria, 'Q' for Queensland, etc, followed by a number allotted by the approving authority) identifying the person or company to who the approval was granted."
The Standards Association of Australia told me that the background information on the origin of the three pin, flat pin plug and plug socket was rather sketchy due to the time elapsed since its initial adoption. However, they supplied the following'.
"(a) The majority of the work would appear to have been carried out in Victoria by SECV with the help of Australian manufacturers.
"(b) The design is virtually identical to a pre-existing American configuration except that the pins are 2 mm to 3 mm longer.
"(c) The configuration was first published as an Australian standard in 1937 as AS-C 112. The current edition of this standard is AS-3 112-1981.
"(d) The current configuration also covers 15 amp and 20 amp 3-pin flat pin configurations. Again, Australia is in the fortunate position as the system was designed so that any plug will fit a plug socket with the same or a higher current rating but not the reverse.
"(e) This system is also used in New Zealand, Fiji and New Guinea, and to some extent in Argentina."
The State Electricity Commission of Victoria was rather tardy in replying to my letter, but a follow-up phone call produced the following:
"Archival records and minutes of meetings dating back to 1927 have been reviewed as staff have had the opportunity to do so and, although some references were noted of comments on the three-pin flat pin plug system, there are no specific comments on the origin of same.
"Inquiries have been made of former Electrical Approvals Board members and other long-serving personnel, but to date no specific information has been unearthed. At the present time we are following two lines of inquiry with retired personnel, but as one has been on extended holidays we have not been able to get in contact with him."
The SECV also made the suggestion that "one possible line of inquiry which may be fruitful may be Mr K Gerard of Gerard Industries (Clipsal) in South Australia as that firm has manufactured three-pin plugs and sockets for many years, possibly over 50 years."
And it was here that I struck gold. Mr Gerard was prompt in his reply and I cannot do better than quote directly from his letter to me:
Prior to World War 1 and during 1914-18, various plugs and sockets were imported from England and used in Australia.
During the early 1920s, it was difficult to import English plugs because of the shortage in production and at the same time it was noticed that a various assortment of plugs was being used in Australia and these plugs had round pins.
"Some American plugs, sockets and cord extension sockets were imported and these were of the flat pin type, ie 2-pin flat pin plug with the pins parallel and the 3-pin flat pin plug which had the configuration of the present 3-pin plug. Late in the 1920s, Ring Grip Ltd of Victoria and Gerard lndustries Pty Ltd (Clipsal) made 3-pin accessories to interchange with the US design.
"As Australia was committed to the 'earthing' system of supply, it was realised that a 3-pin plug was required.
"About 1934 a meeting was called by the SEC V, who was the leading supply authority in those days, at which a representative of the SECV, Standards Association, Mr Tivey from General Electric, Mr Fred Cook from Ring Grip, and Mr Geoff Gerard (my brother) from Clipsal were present. General Electric were importing their own 3-pin plug, etc, from the USA at that time. "The meeting, after reviewing all the plugs (English and American) being imported into Australia, decided to adopt the American 3-pin flat pin plug as an Australian Standard. The manufacturers' representatives considered flat pins were easier to make and their installation machines at the time were capable of making flat pins better then round pins.
"In adopting the USA configuration, the pins of the Australian design were shortened by 3 mm in length because of better safety standards against 'wrongful' insertion into sockets that were then produced and also to lessen the probability of personal contact with the pins when inserting plug into socket.
"A standard plug gauge was suggested, being similar to the one used by Clipsal in their plant, and this was submitted to the Standards Association of Australia and was finally published in a Standard Specification AS-Cl 12 for plugs and sockets in 1937.
This was adopted by all State supply
authorities and hence this 3-pin plug manufactured in Australia by Ring Grip and Clipsal became an Australian Standard.
"The design of 3-pin plugs has had a number of changes over the years since then, but the configuration of the pins has remained the same. People who travel to the USA, UK and Europe realise how fortunate we are to have a standard plug and socket throughout Australia."
I am indebted to those who went to considerable trouble researching on my behalf for supplying me with the information used in the preparation of this article."