Euro Electrics

[Mike]

Even if you count small places like Malta or IoM as countries, I think the US plug comes way ahead.

Plus it's not our 13A plug anyway, it's Swedish.

[Mike]

So you have the freezer on the RCD ?

As a minimum I would expect to see RCD and non-RCD protected (or fast 30mA and slow 100mA protected) circuits.

[Mike]

Well I do regularly see IEE imcompetance in my area of expertise so I don't expect it to be different in wiring regulations.

There is significant rewiring required - the whole of eastern Europe plus most of France, low countries and a lot of Spain and Portugal, Greece and so on. All this is waiting for a harmonised EU standard. I don't see this as a feeding trough for German industry - our own companies should be able to compete well if we are part of the initiative. If we aren't then they won't be able to of course as happens so often with European initiatives.

That is totally incorrect. I have been contributing to standards groups worldwide (IETF, ETSI, IEEE, ANSI, ATM Forum, ADSL Forum, DAVIC, 3PPP, etc) for thirty years and I can assure you all had the goal of producing high quality standards that would stand the test of time.

[Martin Angove]

But for the purposes of (non) diversity you have to calculate maximum demand at the rated capacity of the circuit. If you allow diversity your maximum demand (sockets circuits) is largest+40% of the rest (IEE guidelines in the OSG). There can be a big difference between (say) 8 radial socket circuits serving the house and two or three rings.

[...]

BS3036 rewireable fuses are still allowed in domestic situations for all standard final circuits. You have to derate the cable to account for the greater let-through of energy, but MCBs are by no means mandated.

I don't think anyone is disputing the fact that it is possible for a ring to "break" without any noticeable effects until such time as a sustained overload occurs. What we are arguing is that the circumstances you describe are rare; other faults happen first and are coped with better by a ring. Likewise, even in the case of a break, the chances of the actual load (rather than the potential load) on any one isolated part of the ring being sufficient to cause a problem are low: you'd have to have the break happen near the CU with most appliances connected on the "long" side of the ex-ring.

And it is only small overloads we are really considering. The cable is perfectly safe protected by a 30/32A device for short circuits where hundreds of Amps flow. If it weren't, it wouldn't be allowed for spurs.

You are quibbling the difference between a 27A cable protected at 20A and a 27A cable protected at 30/32A where the fault causes a sustained current of up to 45A to be drawn in one leg of the ring. Above that and the MCB will eventually trip (50A will trip a 32A MCB in around 1,000 seconds). The debate then becomes whether 45A continuously will damage

2.5mm2 cable in such a way as to be the cause of (say) a fire, or whether it is more likely that this low-level overheating will cause insulation to flow, eventually causing a live conductor to short on the CPC causing a dead short, blowing the MCB. I suspect the latter.

It isn't perfect, but it isn't (necessarily) unsafe.

If you're worried, why not wire your rings in 4mm2 cable? At least this is a more practical solution than downgrading the MCB to 20A. Spurring is a bit more difficult as getting 3x4mm2 cables into a terminal is nigh-on impossible...

Hwyl!

M.

[bigcat]

testimony versus evidence. Oft confused.

no they dont

Ahh, theres your mistake. Who do you think promotes these new standards? Or did you really think we were spending billions of pounds to equipotential bond the nations bathrooms in order to save lives? Hint: lives are not being lost as a result of lack of equi.

er yup, no sht. Commercial premises have to meet the latest standards: change the standards substantially and you create a multibillion pound feeding frenzy. With no detectable benefit.

there is none. The stats speak for themselves. Interacting with fixed wiring in the UK is one of the safest things a person can do.

NT

[Peter Parry]

The IEE is usually quite competent. I have no doubt its ability to influence a committee of politically motivated and well bribed eurocrats is exactly zero precisely because it will try to rely upon technical arguments.

Why? They can introduce standards whenever they like if they are needed. In fact France has many standards, all ignored. You think they will suddenly take note of a eurostandard and rewire everywhere? Even CENELEC found this unlikely and required backward compatibility with Shuko in the initially proposed "standard" (but not for some reason with UK systems).

What initiative? To rewire a house costs several thousands of pounds. You really think everyone will say "Herr Blurr says we must so we must"?

I thought that was your Scots "friend"?

They failed miserably then didn't they. Standards and quality are unrelated. There is a standard for a pound weight. It does not make a pound of potatoes of good quality. There is a eurostandard for strawberries - which is why they now all taste like pink water.

[Peter Parry]

Who mentioned an RCD? There is no RCD in the Consumer Unit - far to dangerous.

Never seen a house fire have you?

[Peter Parry]

A Dutch friend has a modern house with a total of 300A of MCB's. On an 80A supply.

He can't add extra sockets because he is already up to some arbitrary limit on the number of sockets allowed on a radial. He has just bought in the local shops several 12 socket extension leads. Ever seen such a thing on sale in UK?

[bigcat]

just as we've explained things to you, but you still dont get them. If everyone undestood everything explained to them, wow would life be easy.

there are no safety problems with UK system. The stats make that clear, even if you cant understand ring circuits.

wrong, obviously. Anyone and everyone has rights to manufacture parts for UK system. And of course many other systems, which are even older, thus also no longer covered by patents.

absence of any evidence or logical explanation noted.

so it is not the best. Financial efficiency is after all one of the requirements for a successful system. It is a daftly wasteful system.

We have. It tells us nothing. There are always people that dont understand the subject, sometimes lots of them.

if you think that argues in favour of your viewpoint you dont understand logic very well.

It ought to be. However in the real world, sometimes they are, sometimes not.

First a goal does not equal an achievement, but that is fairly obvious. Life would be so much easier if all goals were achieved, and none compromised or failed.

Second, this explains a lot. Your grasp of all this is lacking in many areas, not least assorted basic logical errors, and yes, youre involved in drawing up standards. No surprise then.

Sorry, but theres only so much bs for one day before someone calls you on it.

NT

[Peter Parry]

[snip]

You jest? I've got a box full of the damn things. Some are simply PVC and will happily burn at any opportunity (Don't forget it was the Germans who insisted on _lower_ flammability standards for TV's in the EU than apply anywhere else in the world.) You really think a 12 gang unfused extension I bought in Germany is safe? Have you ever known a Shuko plug carry 16A without getting so hot it hurt to touch it?

Apart from the fact that even the well bribed dimwits in Brussels are not contemplating _rewiring_ anything that is the most facile argument since lunchtime.

[dennis]

I have seen 10 way and used 8 way.

[Mike]

Yes - because there will be EU grants to do so.

No it didn't. Where do you get this from.

Before he retired he was EU rep on electrical harmonisation. I work on comms standards and their influence on the semiconductor industry.

Oh don't be so silly. Do you think this discussion could even take place if a whole host of standards weren't in place to allow our comments to get to each other.

[Mike]

So I'm calling you on it. You appear to be displaying an anti-Europe streak which says that everything European is inferior to everything British. Get real.

Fortunately this time there won't be UK veto on harmonisation when the vote comes so it should happen.

[John Rumm]

If it is a circuit protected by RCD that is.

Not all socket circuits need to be RCD protected. Some you would not want to be either (like ones with high leakage, such as IT systems for example)

Without an RCD, 1 ohm as opposed to say 0.5 will keep him connected for a fair bit longer.

Each to his own, but many find 20A circuits less flexible though.

[bigcat]

silly

[dennis]

Why would an IT system have high leakage? There is no reason for it to have any leakage.

There would be no difference between such circuits. The victim would only pass milliamps and there would be no trip without an RCD.

By high impedance I meant something that would actually limit the current to safe values.

BTW if you want to design a circuit that is really safer then it would be possible to add a test box on the end of a radial circuit that measured the drop from the consumer unit and intentionally applied a trip if there was a fault. I don't suppose it was practical a few years ago but it is now and only needs someone to design it and get it approved. It would prevent all these bad joints from being a problem.

[Andrew Gabriel]

Not sure if everyone is assuming same meaning for IT here. He means an Information Technology appliance, not an IT earthing system.

Class I earthed IT appliances are allowed to leak up to 0.75mA each, which means a design maximum of 5 PC's per 30mA RCD typically.

The required RFI suppressors cause it.

[Dave Plowman (News)]

SMPS often have RC networks from both line and or neutral to earth for RFI purposes. Put many on the same circuit...

[Peter Parry]

If countries are that exercised by it they can use national grants. However, I am more than slightly unconvinced that the EU will hand out thousands of pounds per house for rewiring. Even if they were to do so the enormity of the task and the shortage of people capable of doing the work would be such that it would take centuries to complete.

A comment on a 1993 draft document.

I did not say standards were not necessary, merely that they are more often related to what is minimally acceptable rather than good quality. International standards in particular are often simply those which a group of people with opposing vested interests can agree will cause least damage to the interests of each. That does not make them bad or unnecessary but it does mean they rarely have anything to do with good quality. The snail like pace of the standards definition process also means it constantly lag years behind reality.

[Peter Parry]

Noise filters.

See

The filter contains two capacitors from phase and neutral to the circuit protective conductor (CPC), or earth, so a small continuous current flows to earth.