It seems that I may have intruded more than enough on the topic in "Electrics UK" of "Help replacing 2 2 way 2 gang switches that are labelled different." - for which I apologise.
It may (or may not) be of interest to some in the UK to read of "The origins of the Australian Plug" as set out in https://cool386.com/plug/plug.html
There are many interesting "comments" in this document, including :-
"Around 1930 an attempt was made by Clipsal and Ring Grip (the predominant electrical accessory manufacturers at the time), along with the State Electricity Commission of Victoria to adopt the American design as the Australian standard. Associated General Electric was importing the American design from its U.S. counterpart, General Electric, and promoting its use here.
The American design was chosen over the British design because it was easier for local manufacturers to make flat pins instead of round ones."
In more detail it is noted in https://en.wikipedia.org/wiki/AS/NZS_3112
"Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as a formal standard in 1938). The Australian standard of 1937 was the result of a "gentlemen's agreement", reportly from 1930, between manufacturers Fred Cook of Ring-Grip, Geoffrey Gerard of Gerard Industries and Brian Harper Miller of the State Electricity Commission of Victoria (SECV). The design was based on an American plug and socket-outlet first intended for use at 120 V which was patented in 1916 under U.S. Patent 1,179,728 by Harvey Hubbell Inc. By the early 1930s this design had been up-rated to 250 V 10 Amp capacity and this USA firm was supplying the Australian electrical industry with its sockets. Current Australian plugs fit these American outlets perfectly. (While this socket-outlet never became a NEMA standard design, the 50 A NEMA 10-50R, has a similar pin configuration in a larger form.)
Argentina, Uruguay and China based their plugs and sockets on the same design.
New Zealand also adopted the Australian design, since Australian equipment and many electrical appliances were exported to that country."
Also :-
"American wall box dimensions (were) adopted in Australia.
It may also surprise some that it wasn't just the three pin socket we adopted from the U.S, but also their wall box dimensions. Not only are the switch plate dimensions the same, but even the screws to secure the switch or socket into the wall box have the same thread (6-32). It is possible to install an Australian fitting into a U.S wall box and vice versa."
To which I would add - when "metrication" came along in the 1970s Australia, did not change the (thread) "design" of these screws but just re-specified them and continued to manufacture and use them. (https://www.bunnings.com.au/hpm-51mm-long-screws-for-powerpoints-and-switches-10-pack_p7034597 is an example.)
Hence, "modern" electrical wall-plate screws can still be used to secure new devices in walls which were built and fitted with "electrical accessories" in the 1930s - if such still exist !
It may be of interest that the "Digital Museum of Plugs and Sockets" makes this comment at (https://www.plugsocketmuseum.nl/Australian_3hd.html )
"(any Australian) plug can be inserted in a socket of the same or higher rate, but not in a socket with a lower rate. That means that a 10A plug fits in each of the four types of sockets (actually, there are five), but a 32A plug can only be used with a 32A socket. An elegant and safe system."
(See https://commons.wikimedia.org/wiki/...cket_styles_for_different_current_ratings.jpg )
It may (or may not) be of interest to some in the UK to read of "The origins of the Australian Plug" as set out in https://cool386.com/plug/plug.html
There are many interesting "comments" in this document, including :-
"Around 1930 an attempt was made by Clipsal and Ring Grip (the predominant electrical accessory manufacturers at the time), along with the State Electricity Commission of Victoria to adopt the American design as the Australian standard. Associated General Electric was importing the American design from its U.S. counterpart, General Electric, and promoting its use here.
The American design was chosen over the British design because it was easier for local manufacturers to make flat pins instead of round ones."
In more detail it is noted in https://en.wikipedia.org/wiki/AS/NZS_3112
"Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as a formal standard in 1938). The Australian standard of 1937 was the result of a "gentlemen's agreement", reportly from 1930, between manufacturers Fred Cook of Ring-Grip, Geoffrey Gerard of Gerard Industries and Brian Harper Miller of the State Electricity Commission of Victoria (SECV). The design was based on an American plug and socket-outlet first intended for use at 120 V which was patented in 1916 under U.S. Patent 1,179,728 by Harvey Hubbell Inc. By the early 1930s this design had been up-rated to 250 V 10 Amp capacity and this USA firm was supplying the Australian electrical industry with its sockets. Current Australian plugs fit these American outlets perfectly. (While this socket-outlet never became a NEMA standard design, the 50 A NEMA 10-50R, has a similar pin configuration in a larger form.)
Argentina, Uruguay and China based their plugs and sockets on the same design.
New Zealand also adopted the Australian design, since Australian equipment and many electrical appliances were exported to that country."
Also :-
"American wall box dimensions (were) adopted in Australia.
It may also surprise some that it wasn't just the three pin socket we adopted from the U.S, but also their wall box dimensions. Not only are the switch plate dimensions the same, but even the screws to secure the switch or socket into the wall box have the same thread (6-32). It is possible to install an Australian fitting into a U.S wall box and vice versa."
To which I would add - when "metrication" came along in the 1970s Australia, did not change the (thread) "design" of these screws but just re-specified them and continued to manufacture and use them. (https://www.bunnings.com.au/hpm-51mm-long-screws-for-powerpoints-and-switches-10-pack_p7034597 is an example.)
Hence, "modern" electrical wall-plate screws can still be used to secure new devices in walls which were built and fitted with "electrical accessories" in the 1930s - if such still exist !
It may be of interest that the "Digital Museum of Plugs and Sockets" makes this comment at (https://www.plugsocketmuseum.nl/Australian_3hd.html )
"(any Australian) plug can be inserted in a socket of the same or higher rate, but not in a socket with a lower rate. That means that a 10A plug fits in each of the four types of sockets (actually, there are five), but a 32A plug can only be used with a 32A socket. An elegant and safe system."
(See https://commons.wikimedia.org/wiki/...cket_styles_for_different_current_ratings.jpg )
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