ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades History of the Australian plug

Well, I don't have any crowfoot plugs handy (I've rarely ever seen them), but several such are illustrated in the 1960 WESCO catalog. They all appear to have longer ground pins.

What represents an improvement in the 5-15 (apart from backward-compatibility) is that the u-shaped ground pin is too wide to be inadvertently inserted in a live slot.

Although T-slots and older parallel devices have a 250V rating, I doubt they were ever used much on circuits over 120V, since appliances with these plugs were, and are, so common.

Any other plug could be used within its maximum rating. Crowfoots were used for 240V circuits, and for 120V grounding circuits.

I need to get my scanner hooked up, so I can post pages 198-199 of House Wiring by Thomas W. Poppe (1930). Two methods of grounding a washing machine through the cord are illustrated. One involves a crowfoot, and is essentially the same as the modern method. Let's just say the other is scary!

To quote from the original aticle:
"In adopting the USA configuration, the pins of the Australian design were shortened by 3 mm in length".
Only a couple of months back I bought some more old bakelite fittings from the markets. I didn't realise it at the time but looking through my stash when I got home revealed something which I believe is of historical signifigance:

The thing I noticed about this Clipsal plug was the pins were longer than normal. Sure enough comparing to a modern plug:

It can be seen there's a difference of about 3mm.
So, it would appear that this Clipsal plug is pre Australian standards and should be identical to the obsolete US 3 pin design which we adopted. I have never seen another plug like it...and I've seen a lot of bakelite. It does go right into every socket I tried it in, so perhaps the socket depth is still required to take into account the pre 1937 standard.

While still on historical theme, to quote again
"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"
This is probably one such example made by General Electric. I got it of an ancient power board which was also fitted with some equally ancient 3 pin sockets as well as some nice brass BC sockets. It's perhaps surprising there were no British sockets.

Notice it's rated for 250V use...whether those sold in the US are rated at that I don't know. One aspect of the two pin US configuration we never did adopt here was the polarised version (ie. one pin wider than the other). Since locally made stepdown transformers often use the locally made Clipsal socket it's impossible to plug in some US appliances if they have the polarised plug. Also, the local version of the plug does not have holes in the ends of the pins.

[This message has been edited by aussie240 (edited 01-08-2006).]

[This message has been edited by aussie240 (edited 01-08-2006).]

When did BS546 appear?
Also when did schuko first appear?

That GE socket is very similar in overall design and styling to the 5A types BS546 which were used in Britain -- Just change the slots for round pins.


I'm not sure of the date. I think that at least some of the original plug standards predate the existence of the British Standard.

Aussie240,

It looks like that socket says "12.5A 250V". Am I correct?

I've never seen that rating on US-made devices, although some early US parallel and T-slot devices are rated 250V or even 300V.

Although the polarized "NEMA 1-15" became the standard receptacle in the US by the '30s, polarized plugs were just about rare as hen's teeth until 1978. That's not to say they didn't exist at all. The bathroom fans in my 1971 house had polarized plugs, before I replaced them with new ones.

Schuko already existed in the 1930ies, but I have absolutely no idea when it first came up. The idea of grounding was introduced around the 1890ies according to an old code book I once got, but it didn't mention any plugs.

That's quite correct. I've never seen that 12.5A rating on anything else. The locally produced 2 pin plugs and sockets of that configuration are rated at 250V 10A.

1mm might not sound like a lot to those of us that have fully developed fingers.
But, have you ever watched a young child insert the plug into a socket?.
There was a push here not long ago for all kindergartens and primary schools to have the recessed style socket-outlets.
This was before we adopted the AS/NZS Standard and it got lost in the rush to make both sides of the Tasman the same.
All of the Kindergartens I've been in since, still have the standard (although shuttered)socket-outlets.
I tried one with Duspols, with a gap of 12mm you can light up the neon and get current out .
Oh and BTW, there were no RCD's on this installation either, the place was built in the 70's.

Ragnar,

there is a patent for a Schuko-type plug that was submitted in 1923. I thought I had posted a thread about it here maybe a month ago, but I can't find it.

Here is a link

[This message has been edited by C-H (edited 01-12-2006).]

I'm never quite sure what era schuko was used here in Ireland. For a time, we had several standards used simultaniously.

Schuko was certainly common in homes built in the 1930s thru 1950s.

BS546 seems to have been around always, but strongly appears in the 1950s/60s. However, it's common to see old installations where only the 15A sockets were used. Typically one per room.

The 5 and 2 amp versions didn't seem to be in widespread use until the demand for switched/dimmable table lamps became an issue and they were installed alongside BS1363 in the 1970s/80s/90s.

The 15A version also occasionally gets seen behind dishwashers/dryers/washing machines in installations from the 1960s/70s. Each appliance would have been on a dedicated circuit. The main reason for this was that 220V was the official standard here and many appliances were designed around aprox 16A loads (schuko). So, 13A fused plugs wouldn't quite cope. You'd find BS1363 throught the rest of the house though.

BS546 fitted standard boxes, schuko didn't.. hence it wasn't used.

However, we certainly had BS and VDE standards operating side by side for a considerable period of the 20th century.

BS546 and schuko were both dropped in favour of BS1363 as it created a new national standard and removed various questionable earthing arrangements with 2 pin schuko plugs in BS546 sockets etc..

Also, the shuttering etc appealled to the safety authorities at the time.

It's exceptionally rare to find a non-BS1363 outlet in normal use here thesedays. BS546 (other than for special purposes) and schuko have completely disappeared. (although you occasionally see long since disconnected round schuko outlets recessed in skirtings / wood work of some older homes. They were simply never removed as it would be too much hassle.

[This message has been edited by djk (edited 01-12-2006).]