RCDs in series

[Doctor Drivel]

No it would not. There is no reason for those figures to relate to the types of electrical systems. It is more a culture towards safety than the systems.

[John Rumm]

Which exemplifies why low capacity radials are not well suited to general power provision in a home.

One ring circuit for the kitchen, another for the other downstairs sockets, plus a non RCD protected radial for any circuits with low trip tolerance would seem more than adequate in most domestic situations.

Whole house RCDs were briefly allowed in the 15th edition IIUC. So since that covered the '80s basically, the scope when that was acceptable was limited. It fairly soon became apparent that it was not a good solution.

They can, but rarely if ever do in the absence of a fault. I don't recall the last time I need to replace a fuse for a non faulty appliance.

Figures?

Here you would throw the switch above the counter marked "Dishwasher", seems somewhat better to me.

[John Rumm]

Requiring dedicated circuit wiring for each and every appliance.... hmmm novel.

[John Rumm]

as clueless as you.

[Pete C]

AIUI in Holland proportionately to population, the number of people killed by electrical accidents is /half/ that of the UK, and I don't think they have ring mains... do they?

cheers, Pete.

[Andy Hall]

Final circuits in Holland are radial.

The numbers are low in all cases, so it would be necessary to look at individual accidents to see whether the cause was related to circuit protection or other causes

[Doctor Drivel]

???????

They split it up well.

I have seen them on new builds of only 5 years ago and less.

But can do and behind an appliance.

Which looks crap and is not an RCBO.

[Doctor Drivel]

No. The standard in the rest of the world and safer. Ours is cheap - and nasty.

[Doctor Drivel]

It seems the UK is out of step with the rest of them (but thinks it is in step)...as is your brain.

[Andy Hall]

Have you seen French electrical fittings and wiring practices? They are better than the U.S., but that is all that can be said.

The UK system can't be described as cheap or nasty in the sense of the fittings used or the electrical design. In other countries, the radial design does result in the need for many more circuit breakers in an installation, which increases the cost on that side somewhat.

[Peter Parry]

The numbers killed in electrical accidents isn't recorded very consistently between countries. For example some record only electrocution deaths, some would record deaths in a fire caused by electrical faults as "caused by electricity" others as a fire death. There are certain countries in the EU with dire standards - France, Spain, Portugal, Italy, Greece and most of the old East Europeans states amongst them. In these countries deaths primarily caused by electrocution are fairly common.

From a hazard point of view fixed wiring (even French) doesn't cause many accidents directly. The direct difference between ring and radial is also minimal. However, the consequential hazards are not. A characteristic of many continental installations is that there are a smaller number of sockets in a house than for a house of similar age in the UK and consequently much more use of trailing extensions. These are inherently more hazardous than wall sockets and contribute to far more fires of electric origin than does fixed wiring. The lack of any form of appliance lead protection coupled with high trip currents also makes fires caused by equipment failure more common on the continent than in the UK.

All countries using the CEE 7/4 (Shuko) plugs tend to have a number of child fatalities each year caused by objects being poked into the unprotected openings. The UK has virtually no such accidents with the shielded 13A socket.

The Schutzkontakt (Shuko) plug socket pair is designed to be safe in that the side earth contact must mate before the pins and the recessed socket prevents fingers touching the pins as they are being inserted. Unfortunately there are a number of other systems using the same or similar pin sizing and spacing as Shuko but without the earth connection or recessed socket. As a result there are accidents caused by plugging Shuko plugs into sockets where the earth is either absent or ineffective as it doesn't touch the side contacts. A further catch is that in such situations the side contacts on the plug become live so giving a shock to anyone who tries to remove it in such fault conditions. This commonly occurs with the two pin CEE

7/16 (Europlug 2.5 A/250 V) unearthed socket which isn't supposed to fit a Shuko plug but many will. The French 2 pin plug with female earth will also usually fit a Shuko socket - but without the earth making. The CEE 7/7 is a cross between the Shuko and French systems with side contacts and a female earth receptacle and usually supplied with new equipment.

Although rated at 16A it is also possible to buy Shuko plugs with considerably lower current carrying capacity and many "Shuko" plugs are of poor quality and prone to overheating when running at high loads. I have seen some dire examples around of very poorly made Shuko plugs and nothing like the same poor quality in even the cheapest BS 1363 plugs (probably because BS1363 plugs require third party certification whilst manufacturers can self certify Shuko).

Another issue with the continental two pin plugs is that the wiring of the live and neutral is random (and even if it were not the plugs can be inserted any way around). Usually this isn't an issue but it becomes one when freestanding lamps using Edison Screw (the continental standard) fittings. The threaded part of the shell can be left live and shocks while changing bulbs and accidentally touching the bulb thread are common. The shock isn't usually fatal, the fall off the ladder more often is!

There is no question that BS 1363 is a fundamentally much safer system than the Shuko and its variants. This is hardly unexpected as the Shuko design dates from the 1920's.

The improved safety of the ring over the radial stems largely from secondary effects of the greater number of fixed sockets and fuse protection of the appliance lead. Together these reduce the number of fires caused by overloaded and damaged extensions. There is of course nothing to stop you wiring a BS1363 layout in radial form - but there would be no advantage in doing so.

[John Rumm]

Because you end up needing at least half a dozen circuits per floor just for sockets, with all the cost and wiring complexity that entails. You are also stuck with no more practical load than one high current device per circuit - a right PITA in a kitchen for example.

Are you:

1) Sure you know what you were looking at 2) Sure it was not a TT install 3) Not just making up this stuff like normal

can in theory. I have never had it happen. In fact I have not had a fuse blow in anything in the last 15 years that I can recall.

Still waiting...

You are aware that there is no particular advantage to having RCD protection on fixed appliances such as dishwashers? (TT excepted)

[John Rumm]

Figures?

Ours is certainly not cheap, and IME the quality of accessories is usually noticeably higher.

The accident statistics do not support your claims either.

[John Rumm]

Much also depends on if they record accidents with electrical appliances separately from those for fixed wiring, and how they record things like fires started by electrical faults. Without detailed analysis of the stats recording process they as usual tell you a small part of the story.

[David Hansen]

On Thu, 23 Aug 2007 14:34:21 +0100 someone who may be John Rumm wrote this:-

I'm waiting for these too, despite the various claims in other parts of the thread.

Keep up the good work by pointing out the flaws in Mr Dribble's assertions.

[David Hansen]

On Thu, 23 Aug 2007 14:16:13 +0100 someone who may be Peter Parry wrote this:-

This is something I entirely agree with you on. Wiring is something that the UK has got right for a long time, unlike say plumbing which was decidedly dodgy until say the 1960s and the adoption of single pipe drainage almost universally.

[ARWadsworth]

Have you seen the electrics in a remote village in Slovakia? They are definately cheap and nasty. The old high rise flats in the citys are not much better. I wonder what the authorities here would say if a British villager decided to make their own electrical connection to an overhead supply.

Adam

[Andrew Gabriel]

BS1363 family is the most recently designed domestic plug and socket system in the world. It was the result of some 10 years of competition between manufacturers to design a new standard. It has been adopted in whole or part by more countries in the world than any other domestic plug and socket standard. The standard has been further improved a number of times over its

60 year history, and the mandatory testing required is very rigorous.

[John Rumm]

Not much of a challenge is it! Still he seems to have sloped off tail between legs again for now.

[Doctor Drivel]

So that is 8 x 6 which 48 sockets. A lot of sockets per floor.

Ah cost!! Yes rings are cheap....and nasty.

In a kitchen individual circuit for high load appliances is a great advantage in many ways.

Yes. A CU.

I know what I see, You make things up as you are from Essex.

I have.

Lucky man. How about the RCSs tripping the whole house when a 230V downlighter blows. Great eh!!!

Look at the systems. Theirs is superior. Not a cheap ring effort to reduce MCBs. and have a small CU.