Australian standard AS/NZS 3112:2000 has been updated and as of April 3, 2005 requires the use of insulated line and neutral pins. The use of the insulated pins is being implemented in order to lower the risk of electrocution and shock as a result of inadvertently crossing the live pins.

That's a good improvement. Like the old unsheathed pin BS standards (1363 & 546) it seems to be easy to accidently contact the pins.

Grounded recessed plugs (Schuko/French) have been the only ones that have prevented this from happening from day 1 and as far as I know 2-pin Europlugs have had sheathed pins for a long time too, far before BS1363 got them added on.

Plugs intended for a European recessed socket inserted into a flat non-grounded socket can be quite scary, old sockets often contact the pins when they're only very partially inserted too.

NEMA plugs arn't great in this regard either.
Isn't there a sheathed version required in some far eastern countries? (Japan?)

[This message has been edited by djk (edited 09-22-2003).]

Touching the pins of a BS1363 plug was my first experience of how 240V stings!

I was about 4, and went to "Help mommy" unplug the vacuum cleaner. I got the plug part way out and put my fingers behind the plug body to pull it out some more....

Ouch!

The ESB opposed their use here as an offical standard until the pins were sheilded!

Apparently the standards athority was pushing them but the ESB prefered recessed schuko on safety grounds and because it was designed for 16A appliences at 220V which made sense! Considering that a 3000W applience will quite often blow the fuse in a 13A plug here if it's being fed with a steady 220V. The technical standards committees got all flustered over polarity and fusing while the ESB had more sense.

[This message has been edited by djk (edited 09-23-2003).]

Schuko plugs have one more advantage only a recessed system can offer: They hide any arcing from the user. I have had some quite nice flashes plugging in old ungrounded plugs, but with Schuko plugs they don't get out of the receptacle, so there's far less risk of burning something.
Flat plugs have been around for some time, but at the moment they were called Euro plug they had sleeved pins.

BS1363 contacts are so far back in the socket you never see arks either though.

PaulUK: just out of curiosity in Ireland I notice a lot of burn damage around the live receptical of sockets, including well known brands like MK ! Also notice it around the live pin on plugs of heavy appliences quite a lot. E.g. it wouldn't be THAT unusual to see it on a socket where the kettle is plugged in or the dryer.

Those BS fuse cartridges and holders get very hot. I always think the way the fuse makes contact with clips is pretty flimsey in those plugs.

Is that common in the UK? Or are we getting a slightly higher current loading on the pins due to the lower voltage?


[This message has been edited by djk (edited 09-23-2003).]

So when does the new standard come into place?

I'm gonna stock up on the old style Aussie plugs

I wish they would do the sheathing on the American type plugs. The Japanese (who use the same type of plug config) already do it on theirs:



The pins are the same dimensions, so if the Australians can do it, so can the American plug manufacturers.

Also, it would force plug contact manufacturers to drop the silly folded sheet metal blade design that is easily bent and damaged and instead opt for the sturdier solid blades like the Aussies have done.

Unfortunately our standards are not as enforceable...unless you get the idea into the Chinese manufacturers' heads who currently think that ALL American plugs molded onto cordsets have to be polarized to get UL listing... even when its a tape recorder cordset with the figure-8 connector on the other end is NOT polarized!!!

It seems as though it's not just imported equipment being fitted with polarized plugs where they're not really needed.

I have a recent-ish Dremel (120V American-market version) and it has a polarized plug. The tool is made in U.S.A., although I suppose the cordset might have been imported. It's double-insulated with black and white cores rather than SPT type, so are polarized plugs being used on all such identified cordsets now?

I see it a fair bit here too. Some of the cheap BS1363 plugs can get very hot under heavy load, and as you say it seems to be the fuse and clips which cause the problem.

I advise people to use those "el cheapo" plugs on their bedside lamps, radios, etc. if they wish, but recommend a better make such as MK for the washing machine, tumble dryer, heaters, etc.

Most people here would probably argue that visible arcing shouldn't be a problem due to the majority of outlets have integral switches.

Switched receptacles are so much the norm here that some people are under the impression that the regulations require them, at least in domestic work. The only time the IEE Regs. specified an integral or adjacent switch for general purpose outlets was on DC systems.


[This message has been edited by pauluk (edited 09-23-2003).]

Paul,

My Dremel Moto-Tool is also like that. Ditto a double-insulated electric drill I have. Both also have the flimsy folded-sheet metal blades so they will someday be replaced by sturdier (non-polarized) caps.

It is easier to find non-polarized replacement plugs in hardware stores anyway.

The cordsets are available in un-polarized versions, but I guess the manufacturers just want to play it easy and safe.

What is the difference between the cheapie plugs and the MK brand? I've used the MK brand British plugs and like the fact that they have American style wrap-around terminals.

Other brands don't. They have those grub-screw type things instead. Is this the reason? I've used the second kind also and you have to double and bunch up the wire so the screw can bite into it securely.

The MK wire terminals are certainly well designed. The nuts with captive retaining clamp and washer have been used on MK plugs since at least the 1950s.

As you say, most other brands have the screw and hole method, and doubling over the wire is just about essential on the smaller size conductors.

The overheating problem seems to be from the fuse clips. The MK type (and other good brands) clamp the whole length of the fuse's end cap, whereas many of the cheap brands seem to have rather thin clips which only "spot grip" the caps in a couple of places.

If you run say 2 or 3kW heater for a half hour, you can often feel the right-hand side of the plug getting quite warm.

Greetings from Berkeley, California

After reading this, I checked the two blade plugs on my appliances. They are all solid metal, not folded, with the exception of a grounded to ungrounded adaptor.

The two blade plug also has a flared bottom, making it hard to get at the blades while removing it from the receptacle. From personal experience I think this works well.

In my local area, I see the many different plug configurations from other countries, and I have found this forum to very helpful in understanding how and why things are done differently.

I hope I can add to it as well.

Gene


[This message has been edited by GeneSF (edited 09-25-2003).]

Hi Gene, and welcome to ECM.

The individual countries in Europe, each smaller than many American states, certainly led to a wide variety of plugs and wiring arrangements over the years.

As you might have gathered from some other posts here, there is a gradual move toward a common European system in many respects, and on the plug issue Schuko seems to be becoming the de facto standard across the Continent.

It is still opposed by the British IEE on two main grounds: (a) It is not polarized, and (b) in its basic form it is incompatible with our peculiar ring circuit, which the IEE seems unwilling to abandon.

I think the IEE will eventually buckle at least on the ring circuit idea if not on the actually plug/socket arrangements.

Look at how quickly the Ceeform plug/sockets sytem replaced various national standards in industrial and 3-phase situations.

Thanks for the welcome, Paul

While I like my NEMA plugs, I'd feel better with the layers of safety that a BS1363 or Shuko system would give me in 230V wiring.

So if the Shuko system is not polarized, is this much of a safety hazard?

Gene--

[This message has been edited by GeneSF (edited 09-25-2003).]

Gidday there Gene,
Welcome to ECN!.
C-H,
The wrting has been on the wall for our plugs, for some time and I am suprised that we have had un-insulated pins for so long.
I read an article recently and I'll post a link to it, if I can find it.
Unfortunately, this measure probably won't save a lot of lives here, accidents happen here because of broken sockets and the like.

People seem to have quite differing views on this.

There are one or two cases where polarization is desirable, so it would be nice to see a system which can accept non-reversible plugs where needed, but for most portable appliances, it really doesn't matter.

My fellow Brits may have a different point of view on this!

Most modern appliances sold in Europe have double-pole switching, so polarization is hardly an issue. Concerning table lamps you're simply advised to pull the plug before changing the bulb. Also our light sockets are built to ensure the bulb loses contact to both terminals after only a fraction of a turn. The screwshell itself isn't connected to the terminals like it is in US sockets. So all countries who _have_ Schuko consider polarization pretty useless. Even French and Swiss, whose sockets are polarized if grounded plugs are used don't really care about how the receptacle is wired. I think the french ones don't even have markings on them, so it's your choice where to put hot and neutral. I once heard the weird theory that horizontally mounted receptacles should have the hot on top, 'cause in case of a flood the hot would be flooded last...

A bit OT, but: People are selling quite strange stuff here. I recently got an old external MO drive the original owner purchased right here in Austria. On the back it had 2 NEMA 5-15 outlets. Never seen anything like that before! Power input was standard IEC computer connector.

All of the corded power tools we bought in the past few years, are polarised solid prongs.

Trumpy, pleased to meet you. I will go over the past topics to become better aquainted with everyone.

Prior to grounded outlets becomming common in US homes, most tube radios had the L wire to the switch and the N to a metal chassis.

If the plug was not polarized and especially if a knob was broken, exposing a metal piece, anyone could get a nasty bite. It happened to me trying out a vintage radio in a thrift store.

Now with better design, such as recessed screws and plastic enclosures, it seems it is not the problem it once was.

I have a collection of several outlets, British, Schuko, AU/NZ, and Japanese. IMO if they are properly constructed, installed, and used, getting shocked should be a hard trick

I'm not certain anyone's scheme should be universal, each country came a long way in getting their own regions on the same page
regarding standard voltage, frequency plug configurations and safety. It's far easier fitting imported equipment with the proper plug than to ask any nation to rip-up and rewire everything.

Gene--

[This message has been edited by GeneSF (edited 09-26-2003).]

[This message has been edited by GeneSF (edited 09-26-2003).]

With regard to T-R's commenta, here's what the typical ES lampholder from Europe is like:

The screwsheel will only become to connected to one side of the supply once the bulb is screwed down into the holder and makes contact at the bottom.


As most British bedside lamps use the double-contact bayonet fitting, polarity on these holders is completely irrelevant:



Where there's an integral switch, obviously there's a possibility of it ending up in the neutral with an unpolarized plug. I really don't see this as a big problem either. Millions of these lamps were in use in the days when reversible plugs were commonplace here.

Arguments that somebody might poke around in the lamp socket without unplugging it first don't make much sense to me. Even if the switch is on the hot side, that same person could just as easily stick his finger in the socket with the switch on.


Gene,
Have you read this thread ? (Mention of live-chassis radios on page 2).

This was indeed a problem where somebody fitted incorrect screws or other mountings to a live chassis set without realizing the dangers. They might have used it in their own house for years with the chassis connected to the neutral and never noticed anything wrong, but if that same set was then moved and reconnected the other way round it would sit there ready to bite some unsuspecting person who happened to touch the wrong screw head.


[This message has been edited by pauluk (edited 09-27-2003).]

The old radios i've come into contact with here in Ireland didn't even have the wires colour coded so I don't think polarity made a lot of difference. They were wired with twisted pair cables just like the cables used on lamps and the 2-pin schuko style plugs were reversible.

Also as a matter of interest a lot of irish pendant light fittings arn't polarised at all. The cable running from the ceiling rose to the lamp is quite often white twisted pair with so either terminal could be live, not that it matters with the BC connections normally hanging from them. This type of cable seems to hook around the grips inside the rose and the lamp holder much better and also looks nicer.

Most older lamps here too would have used this type of cable right up to the plug. Schuko plugs gripped the cord perfectly however, with BS plugs you often had to tie a knot around the cord grip to ensure it held correctly. There was a double pole press-button switch used in the middle of the cable too. Although im sure in many cases it was single pole.

Very old appliences like vaccum cleaners also used heavy twisted pair in some cases! This was usually inside a cloth cover but the terminals sometimes wern't identified. Just two black cables and a green for earth!

djk,
Our pendant fittings are the same over here.
For years our pendants were connected with 2-core lamp cord, wrapped as you say around a torturous path in the pendant itself.
BTW, do you guys have a maximum wieght limit for pendant light fittings over in Ireland?.
By memory, I think it is 0.5kg for .75mm2 2-core.
I'm reminded of a guy over here a few years ago, that ended up in hospital w/ concussion, after a heavy glass shade that was fitted to a pendant pulled the wires out of the cieling rose and fell on his head.
And from a 12 foot stud cieling, this must have hurt somewhat!.

The twisted pair pendant cords, usually with each conductor individually cotton covered, used to be very common in England too, as did plain PVC-insulated twisted pair for radios and bedside lamps.

New rules in the mid 1970s, however, required cords to be double insulated, so they've gradually disappeared. I still see some old pendants fitted with the twisted pairs from time to time.

That's not to say that double-insulated and coded cords weren't in use on radios long before that. A lot of early 1950s sets gad it, with the standard red and black inner cores.

Even the twisted twins were coded sometimes, in that once you strip the insulation you'll see one wire has bare copper strands while the other is tinned to give them a silver appearance. The latter is the neutral, although you can't guarantee that somebody who didn't realize the code hasn't rewired the thing at some point and mixed them up.

Flat, 3-conductor zip-cord (kind of like a 3-wire version of American SPT1) was used on some radio equipment in the past. The center conductor was used as earth, and generally fitted with a green sleeve at the plug end to identify it, but the other two conductors were not always identified. I have an early 1960s Marconiphone phonograph wired that way.

On the modern BC pendant sets, I find that the round double-insulated cords take quite a time to straighten out properly after installation, unless they have a heavy fixture hanging on them.

Yeah there is a maximum weight limit I'm sure but generally common sense applies.

Some of the very old ceiling roses have 3 hooks around the sides so that heavy shades could be hooked on with chains. Generally though anything heavier than a normal shade will have to be installed instead of a ceiling rose / pendant. I haven't seen too many glass shades that can just be screwed on to a lamp holder.

That must have really hurt though! Ouuch!

Most pendants thesedays have a round blue/brown 2 core cable going into to the top or 3 core if it's not a plastic bulb holder.

Here's a fancy brass ceiling rose with hooks


Still find plenty of old twisted pair telephone cabling too around houses too always Grey and white.


[This message has been edited by djk (edited 09-27-2003).]

Paul,
Just a comment,
Yes, it does, but have you ever taken down a piece of the old fabric covered two core during a rewire and noticed how the wire retains it's straight form after it has been hanging down for many years?.

Yeah, funny that....

There's one handing here for 22 years and it's still not straight!

djk,
Just as an aside, at least your brass looks reasonably authentic, not like our fauxbrass, ex China!

Picture of the improved Australian plug



Link to big picture