Wiring of European plugs - live/neutral??

[TTT]

Surely you only need the first and second - you can use them together to crate the third?

[Anthony R. Gold]

The point is that other countries could have adopted this and did not and I doubt that is because the possibility was never considered. Of course the entire ring system was born of post-war poverty and the copper shortage.

Tony

[John Rumm]

In this case you are assuming that the internal overcurrent protection in the PSU will protect the flex[1]. This does however leave a *small* risk that the flex gets reused on another appliance with a higher load.

(However since the connector choice will usually limit what you can connect the flex to anyway this is not usually a problem in real life, unless someone gets inventive with home made adaptors - the telefunken socket to four way socket outlet might prove interesting! ;-)

[1] This is a similar arrangement to the way a spur from a ring circuit is protected - the protection from over current moving to the destination end, and the protection from fault currents remaining at the origin.

[Anthony R. Gold]

I understand the sequence to be that post-war poverty and copper shortage led to the power ring. The power ring resulted in bringing 3kW to each and every power outlet, and having 3kW power available everywhere requires additional protection for appliance cords and flexes. AFAIK no country wires radially with the requirement that 3kW is available to each appliance outlet.

IMO, in this chicken and egg argument, it is poverty>ring>3kW>fused plugs. but you may see it differently.

Tony

[Andrew Gabriel]

They have to be short, so they can pass the fault current required to trip a 16A breaker. In practice, this doesn't seem to be a problem. The only effect in the UK when our appliances became subject to EU rules in this area was that the lengths of such flexs are now limited to 2 or 3 metres. When using a 3A fused plug, the limit on length was much longer than was ever likely to be encountered.

Most appliances don't have a failure mode whereby they can overload their flex, so there isn't a risk of running 15A continuously through a 3A flex. The flex does have to handle a fault current though (dead short), and pass enough current so that the 16A breaker trips before the flex overheats. This requires the flex resistance to be low, and hence the limit on flex lengths.

The one item which completely screws up such design considerations is an extension cable. These are routinely available in lengths and sizes which are not intrinsicly safe. Even if they weren't, people would still plug them together to contrive to make them so.

[Andrew Gabriel]

All the countries which have redesigned their final circuit arrangements since we did so post war have adopted the UK 13A plug. I think that speaks volumes for it. (I'm less clear how many of these routinely use radial verses rings.)

Of course, most countries are still stuck with much older designs.

Ever get that feeling of deja vu?

[Rod]

Which countries have been in a position to do so? (Basically, that means after the UK had implemented the fused plug.)

From what little I know, it appears that most countries have only really been able to adopt an existing system wholesale. One country with which I was a bit familiar was the UAE - where every socket seems to be standard UK 13-amp and every plug is fused. (But I do not know what circuitry lay behind them.)

I cannot imagine any country other than USA, Russia, China or India, or maybe a major trading block like the EU, could now implement any significantly different system. And those would have their work cut out trying to do so.

[Dave Plowman (News)]

You don't need to prove common sense.

[Dave Plowman (News)]

Can you name any developed country which has changed their plug and socket design - apart from the UK?

That was one advantage, yes.

Are you old enough to remember the bodges that existed before final ring circuits?

[Anthony R. Gold]

Codes live and evolve. It was suggested that just adding fuses to exiting plugs would be "a good idea" and there is nothing in the design of the French or Swiss plugs to prevent such a code "improvement" to add that feature (although the fuse would presumably need to be inserted perpendicular to the wall and not parallel to it).

Adding fuses does not require a different system and I understood the point of the original suggestion to be that other systems as they now exist would gain a benefit from the addition of fuses in plugs.

Tony

[Anthony R. Gold]

I understood the "good idea" to be the addition of fuses to plugs in existing systems. Where is the need for changing the sockets and what prevents wealthy European countries from making such an "improvement"?

Tony

[Anthony R. Gold]

I am impressed that a half-baked idea posted just today in this newsgroup has already earned the status of common sense. I have witnessed a miracle.

Tony

[malc]

But a resistor between L & N only simulates a load so it won't trip the RCD. A RCD relies on an imbalance between the current in the Live wire and the current in the Neutral wire. So the test will put a resistor between L and Earth or between N and Earth. If you put a resistor between L & N the same current flows in both wires so won't trip the breaker.

Trust me I work with electricity every day.

[Martin Crossley]

Brazil, to a new one slightly different from a Swiss one, Denmark, (from one that, as well as the correct one, accepted German/French plugs but didn't connect the earth) to the French type, Italy: from the wide-spaced 16-A one to a Shuko variant with an extra earth in the middle, to also accept their 3-pin 6-A plugs. Australia, from various old British types. USA, but just added an earth to the existing type. Republic of Ireland, from Schuko plus the odd old British type, to UK type.

Yes!

[Mike Humphrey]

The resistor goes from output L to input N (or vice-versa), bypassing one side of the transformer.

Mike

[Andy Burns]

But the way Dave showed the resistor and "T" button diagonally across the current transformer, it would register as an imbalance and cause it to trip, besides RCDs that I've fitted don't *have* an earth connecton.

Hmmmm.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Anthony R. Gold" saying something like:

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Dave Plowman (News)" saying something like:

[Anthony R. Gold]

Which half - they could not adopt plugs with fuses or they did adopt them?

Tony

[malc]

Bloody ASCII art.

If there is no earth connection then it could still work as an RCD because RCDs rely on the leakage created by a fault down to earth/through you or whatever. So long as the current comes out of the live and doesn't return to neutral there will be an imbalance and the device will trip [1]

Heh!

[1] OK I know we're talking about AC here but for simplicity's sake...