A while ago I said I'd post a pic of the older round-pin British plugs, officially known as BS546 types. Here it is:

Top row, left to right are the 2A, 5A, and 15A 3-pin plugs. Below left is the current 13A fused type for comparison.

Bottom right is the 2-pin non-grounding 5-amp plug, which is reversible. This type is still the standard "shaver" plug on our xfmr-isolated bathroom outlets. There was also a 2-pin 2A style, and pre-war a 2-pin 15A type.


[This message has been edited by pauluk (edited 09-01-2002).]

{Recent edit only due to image being moved to ECN server}

[This message has been edited by pauluk (edited 09-10-2003).]

Paul,
What year did the use of the current
BS 4343 plugs, start?
Just wondering?.

Do you really mean BS4343? They're the heavy-duty commercial types in various pin configurations and color coded for different voltages. I'm not sure when they were introduced without looking it up.

The 13A plug bottom left of the pic is to BS1363. It was introduced with the ring circuit in the late 1940s, I believe either 1948 or 1949. The older round-pin styles continued in use for many years though.

Sorry Paul,
What I really meant was the BS 1363
three pin square plug, not the BS 4343
Industrial plugs,now under IEC 309.
It has been some time since we actaully
used British Standards,over here.
And of course, there are so many standards,
Regulations and Codes of Practice,to be
complied with over here, you dare not
even sneeze.

That raises an interesting question:

Did N.Z. ever use the BS546 round-pin plugs? If so, when did you change to the flat-blade Aussie-style plug?

For the benefit of those who have not seen the Australian and New Zealand plugs, I have illustrated some examples below. They are also used in Argentina, slightly modified to take a thin pair of round pins (an alternate plug) in the pair of inclined slots. Note also the silver earth (grounding) pin of the bottom plug is stamped "GREEN". Dabs of brown and blue paint (the colors of the live and neutral wires) are present near the compression screws of the other pins.



Interesting question you raise Paul about the use of the old round pin plugs in the Dominions. I wonder what India used and what it uses now.

Paul,
I have seen round pin type plugs,
used in some really old places, that I
have rewired, but I have never bothered
to check the British Standard on them.
And I am quite sure that they would have
been BS type, as all of the fittings and
plugs were made of bakelite, a popular
material, in fittings imported from
England, around the 1920's-30's.
We also used to import TRS(Tough Rubber
Sheathed) cable from a factory, in
Manchester, we are now taking this stuff out in huge amounts, as it is starting
to break down, it has been known to burn
houses down, as it is still protected
by porcelain semi-enclosed fuses, which
normally do not blow, until it is too late.
But, with regard to the BS 1363, fused
plugs, this is a really good system,
especially nowadays, where appliances
depend on the Rupturing Capacity of the
protection at the switch board, what-ever
this may be, to protect an appliance,
which, normally is full of semi-conductors,
not good, fused plugs should be used more
widely!.

There's still a fair quantity of the old TRS cable in use in England too, although it's gradually diminishing as places are rewired. Most of it by now is getting to the point of being very brittle and crumbly, especially the ends entering light fixtures. Most of the latter just fall apart as soon as you touch them by now.

India used BS546 round-pin plugs, and still does according to sources I've seen. You'll also find that they were adopted in many other British-influenced places, e.g. Kenya and some other African countries, and a few Caribbean islands such as Dominica. Some have since adopted the fused BS1363 plug, but others have stayed with BS546 types. (Some British places use American plugs and 120V supplies, e.g. Bermuda, British Virgin Islands. I assume this arose simply due to the geographical convenience of having America on their doorstep to supply lots of cheap electrical parts.)

Thanks for that pic Hutch. The Argentinian plug also has active & neutral the opposite way around to Australia/N.Z. Maybe this ties in with the item I mentioned elsewhere about the Aussie/Kiwi plug not having the active/neutral positions defined at one time. Presumably Argentina also decided to define them and ended up with the opposite scheme.

By the way, you can find a reasonable list of supply systems and plugs at this link.

I say "reasonable," because I've seen some similar lists which appear to contain numerous errors. I can't say this one covers everything, but it's better than many.


[This message has been edited by pauluk (edited 09-05-2002).]

Paul said:-
"The Argentinian plug also has active & neutral the opposite way around to Australia/N.Z. Maybe this ties in with the item I mentioned elsewhere about the Aussie/Kiwi plug not having the active/neutral positions defined at one time. Presumably Argentina also decided to define them and ended up with the opposite scheme."

Paul - Could you please point me in the direction of the thread you mentioned or possibly elaborate some more. It appears outrageous that a polarised plug and socket system can be designed and the polarities are not fixed up front.


[This message has been edited by Hutch (edited 09-05-2002).]

Hutch, in your 9-04 posting, the cap and plug pictured is similar to what in the US used be called—in slang—a 'crowfoot' device—for its shape. Both were rated 125/250V 3-wire, non-grounding, but the grounded-neutral pin was improperly used as an equipment-ground connection. The 50A version was sued for electric ranges, effectively replaced by a 4-wire device nowadays. The 15A version was used for small 240V air conditioners and heaters. The physical layout, pin geometry and proportions compared to the devices in your picture look very much the same.

Well, I thought I'd mentioned it on ECN before, but I've done a search on all my messages on "Australia" and "Australian," and can't find it, so maybe I didn't post on this subject.

I remember reading about the non-defined active & neutral positions in an article in "Electronics Australia" a few years ago. It was in relation to an old two-way receptacle adapter which had active & neutral the opposite way round on the two outlets.

BJ,
I'm not sure if the angles and spacings are exactly the same as the U.S. "crowfoot" outlet, but as far as I can tell the blades on a normal Australia/New Zealand plug are the same size as those on an American 15 or 20A plug (but without the holes).

Bjarney,

I take it you are talking about a NEMA 10/20 - 125/250V:20A.

I recently saw a set of these plugs and extension cord recepticles at an out-of-town hardware store - it's an area dominated by trailer homes, is this a coincidence? I'm going to take an Australian plug down there to see if it fits and will let you know.

What you say regarding grounding though confuses me. Are you saying that for old (NEC <= 1993) 30A and 50A 125/250V circuits it was OK to bond the frame of the appliance to the grounded wire (neutral) wire but not with a 20A 125/250V (Crows-foot) circuit?

[This message has been edited by Hutch (edited 09-07-2002).]

Hutch — Yes. The newer 4-wire versions are NEMA 14-30 [typically for electric clothes dryers] and 14-50 [typically for electric cooking ranges.]

Some US travel trailers have a 125V, 30-ampere "sort-of-crowfoot" plug and cap that is not a NEMA standard. I don't know its evolution. They also use {sometimes multiple} NEMA 14-50 plugs for larger power demands for travel trailers.

Marine applications typically use one or multiple locking 125/250V 50-ampere 4-wire devices [NEMA L14-50] for shore power.




[This message has been edited by Bjarney (edited 09-08-2002).]

I managed to compare the OZ/NZ plug above with a NEMA 10-20. Shape, relative pin size and angles are almost identical however the antipodean equipment is about 85% of the US size

Time to revive an old thread

I have one of these adapters, made by Kopp.



Four of these plugs are simple enough to figure out: British 13A and 5A combination, Australian, American 15A (unpolarized) and European (Swiss).

The fifth is a bit odd. It is supposed to be British. It has two 16 mm long round pins (5 mm dia) on 16 mm centres. I suspect that this is an old ungrounded 2A plug (BS 372???) but I cannot for my life figure out why they would put something so obscure on a travel adapter. Could anyone help me out?

[This message has been edited by C-H (edited 10-27-2002).]

C-H
Re your Kopp adaptor.
I could be wrong, but I think that is the same size as you would find on UK shavers & electric toothbrush adaptors, but with part insulated pins.
The only place you would find such a socket in a modern UK installation is the isolated shaver socket used in bathrooms. But bathroom shaver sockets take international plugs.
Could be some other countries (old British colonies) still use that type of socket.


[This message has been edited by David UK (edited 10-27-2002).]

Yes, that will be the old British 5A type of plug, judging by its size relative to the others.

The U.K. 5A plug differs from the Continental 2-prong plug in that the prongs are slightly shorter, slightly thicker, and set slightly closer together. (C-H, the old British 2A plug is considerably smaller than this one).

I wouldn't be at all surprised to find it still installed as standard in some African countries.

As David said, modern shaver outlets are generally designed to accept British, European, American, and Australian plugs for the benfit of travelers (many also provide both 120 and 240V via the built-in isolation xfmr).

There are some outlets still in use in older properties which were designed only for the British 5A plug though. European plugs will go in though with force, especially if the plug has the softer type of molded plastic which allows the pins some movement.

Compare this with my photo at the top of this thread -- The plug at the bottom right is a 2-pin 5A type.


[This message has been edited by pauluk (edited 10-27-2002).]

If you can get the European plug into the same socket as this plug, either the socket has very big holes or you have a very flexible Euro-plug. It doesn't really show in the photo, but the pins are much closer together than the Euro-plug.


Do you have this plug? Could you measure the distance between the pins? (Sorry if I'm troublesome...)

The package lists some British ex-colonies for this adaptor, can't rember which though.