Continental plugs don't have fuses, so why does UK?

[JohnW2]

Thing is you are roughly twice as likely to die from an electrical fire than from electrocution. Though all the numbers are really small. You are about as likely to die from electrocution as getting dressed in the morning
http://www.esc.org.uk/industry/policies-and-research/statistics/
That's 28 deaths from electrocution and 48 from electrical fires.

Indeed. We've discussed that ESC document, and some of the rather iffy data it contains, unpteen times. However, the death data is probably roughly right and, as you know, of those 48 deaths due to 'electrical fires', 15 were due to 'articles too close to heat' and 12 due to misuse, with only 21 due to faults - and of those 21 faults, I'd suggest that few, if any, will have been due to appliance flexes catching on fire.

I don't really disagree with concept of the point you are making, but with everything to do with electrical safety, there are (remarkably) so few deaths in the UK, due either to electrocution of 'electrical fires', that it's really impossible to determine anything, or make any points on the basis of, deaths. You illustrate that yourself with what you say about the mortality of getting dressed. IIRC, falling out of bed, eating (choking on food) and many other everyday activities are even more common causes of death.

Kind Regards, John

 

[JBR]

Then there is the whole issue of safety of the sockets themselves. For example the standard Schuko socket is unshuttered and unpolarized which makes it less safe than BS1363 even without the fuse issue.

I apologise if I sound a bit thick; I am not an electrician, just an interested party.

How do the Germans (and others) manage with unpolarised Schuko plugs and sockets? Yes, in most instances - lighting for example - polarity is unimportant (unless it's an Edison screw!), but what about appliances where polarity is important? Don't some types of motor need the correct polarity, for example?

 

[JohnW2]

How do the Germans (and others) manage with unpolarised Schuko plugs and sockets? Yes, in most instances - lighting for example - polarity is unimportant (unless it's an Edison screw!), but what about appliances where polarity is important? Don't some types of motor need the correct polarity, for example?

No, with a single-phase AC supply, polarity is never relevant in terms of function. As far as the load is concerned, all it sees is two conductors with a potential difference between them, the polarity of which reverses 50 (or whatever) times per second, and it sees absolutely no difference between them. In fact, the only difference between 'line'/'live' and 'neutral' is that things are usually arranged so that the latter is close to earth potential, with the 'live' hence being the one that is at a dangeous potential above earth. Polarity is therefore only relevent in terms of safety issues - such as the Edison Screw issue you mention.

Probably the most important issue with equipment supplied via unpolarised plugs is that any switches in the power lines within the appliance/equipment being supplied need to be 'double pole' (i.e. disconnect both L and N). If they were only single-pole, there would be a 50% chance that they would switch only the neutral, leaving the live still connected to the appliance/equipment.

Kind Regards, John

 

[ericmark]

With TT earth system and all pole RCD protection if the neutral live wire touches earth the RCD will trip making the system fail safe. In the main German systems are RCD protected they adopted them well before we did so getting the line and neutral swapped will in the main still give protection.

With a TN earth system the currents to earth can be a lot higher and we often use single pole MCB/RCBO protection rather than all pole and we rely on all fuses and switches disconnecting the line conductor. Where the single pole switch or fuse ends up on the neutral conductor the fuse and switch afford little protection from fire or shock. Coupled with the fact we have as yet not fitted RCD protection to most of our houses the dangers of swapping line and neutral are far higher than in Germany.

There is also the tradition, or training we have be brought up with a relativity safe system, and have tended to rely on that safety, with people, including electricians, doing things like switching off with a single pole MCB or switch rather than isolating with the all pole isolator before doing work.

We talk about a widow maker cable between generator and house here and consider them extremely dangerous yet walk around the streets of Turkey and you will see these leads coiled up on top of many stand-by generators. The Turks know the danger and manually protect themselves following careful procedures.

To try and train a countries population that what they have been doing for years is now dangerous is hard. So to put in reversible plugs and sockets in the UK where we are use to the safety provided by our non reversible would be folly in the same way as trying to train the Germans to take the extra care required and remove all the RCD's.

I still have a metal cased Wolf Cub drill with the case earthed and single pole switching. To use that on the German system would be far more dangerous than with British. But my double pole switched double insulated Black & Decker drill could be used in either country.

To convert to German system we would need to have a conversion team like used to convert us to North Sea gas from town gas to remove all the unsuitable appliances. That will just not happen.

 

[JBR]

Thank you both for making that completely clear. I can see that we have adopted a safe system in this country compared to some others. Of course, it would be even safer if everyone had RCD protection as well. We have an RCD in our consumer unit but, as far as I can tell, this is only on the power circuits and not lighting.

My mistake earlier; I think what I had in mind were DC motors.

 

[JohnW2]

Thank you both for making that completely clear. I can see that we have adopted a safe system in this country compared to some others.

It's difficult to argue that polarised plugs and fuses in plugs do not, at least theoretically, result in a 'safer system' but, as you will have seen, there is scope for discussion as to whether , in practice, it has an appreciable impact on safety. There are also some senses in which it can be argued that the concept of a ring final sockets circuit, as very widely used in the UK, is theoretically somewhat less safe than the system used in othet countries.

Of course, it would be even safer if everyone had RCD protection as well. We have an RCD in our consumer unit but, as far as I can tell, this is only on the power circuits and not lighting.

Very similar comments. There are a lot of estimates around regarding the potential saving of lives, injuries and fires that could result from universal use of RCDs. Whilst one assumes that there must be at least some injuries/deaths/fires that have been avoided because of the presence of an RCD, it is very hard to find any convincing evidence that the number of such incidents has fallen appreciably as a result of the widespread introduction of RCDs (about 50% of UK homes are now regarded {by ESC} as having 'adequate RCD protection').

My mistake earlier; I think what I had in mind were DC motors.

Indeed, DC is a totally different issue. Not only will DC motors often run backwards (or not at all) if one reverses polarity, but a large number of DC-powered things (particularly anything involving electronics) will fail to work and/or be damaged by incorrect polarity. Similarly, with 3-phase AC, incorrect 'phasing' (the 3-phase 'equivalent' of polarity) of the 3 'lives' can result in such problems as motors running backwards.

Kind Regards, John

 

[clifford1]

Until the introduction of square-pin plugs we too had unfused plugs.

Also I remember large 2-pin round plugs rated I think at 10 amps, for intermediate load appliances. I still have some of those. The plugs can be inserted either way round, but presumably people normally instinctively orientated them with the wire exiting downwards.

Table and standard lamps were small 2-pin, unearthed, with single pole brass switches.
Electric irons were commonly plugged into lightbulb sockets with an adaptor.

All potentially unsafe, I suppose?

 

[JohnW2]

Until the introduction of square-pin plugs we too had unfused plugs.

We did, indeed, but they appeared in the days before ring final circuits, when power circuits were generally prtected by 15A fuses. I'm not sure whether it ever happened, but I would imagine that it would not have been compliant with regulations, even back in the 50s, to install ring final circuits using round-pin sockets - the main idea of introducing BS1363 plugs/sockets was to facilitate the in-plug fusing, to overcome the fact that the circuit was only protected by a 30A fuse

Also I remember large 2-pin round plugs rated I think at 10 amps, for intermediate load appliances. I still have some of those. The plugs can be inserted either way round, but presumably people normally instinctively orientated them with the wire exiting downwards. Table and standard lamps were small 2-pin, unearthed, with single pole brass switches. Electric irons were commonly plugged into lightbulb sockets with an adaptor. All potentially unsafe, I suppose?

That's all very true and, as sometimes discussed here, there were some truly frightening 'adapters' around. I can recall 'Christmas Trees' of connections hanging from lightbulb sockets in my grandparents' house!

Kind Regards, John

 

[jabuzzard]

Then there is the whole issue of safety of the sockets themselves. For example the standard Schuko socket is unshuttered and unpolarized which makes it less safe than BS1363 even without the fuse issue.

I apologise if I sound a bit thick; I am not an electrician, just an interested party.

How do the Germans (and others) manage with unpolarised Schuko plugs and sockets? Yes, in most instances - lighting for example - polarity is unimportant (unless it's an Edison screw!), but what about appliances where polarity is important? Don't some types of motor need the correct polarity, for example?

Higher rates of death and injury I would imagine is the main difference. Needing everything to be double pole switched another.

 

[jabuzzard]

Indeed. We've discussed that ESC document, and some of the rather iffy data it contains, unpteen times. However, the death data is probably roughly right and, as you know, of those 48 deaths due to 'electrical fires', 15 were due to 'articles too close to heat' and 12 due to misuse, with only 21 due to faults - and of those 21 faults, I'd suggest that few, if any, will have been due to appliance flexes catching on fire.

I don't really disagree with concept of the point you are making, but with everything to do with electrical safety, there are (remarkably) so few deaths in the UK, due either to electrocution of 'electrical fires', that it's really impossible to determine anything, or make any points on the basis of, deaths. You illustrate that yourself with what you say about the mortality of getting dressed. IIRC, falling out of bed, eating (choking on food) and many other everyday activities are even more common causes of death.

Kind Regards, John

Which brings Part P into light as a huge waste of money. Put another way for the same cost you could have saved many more lives doing other things.

That said there are a lot of electrical fires, and while few cause any deaths it should give a clue as to where the risk lies. Again it mostly appears to be in appliances so Part P will have had little to no effect anyway.

 

[JohnW2]

Which brings Part P into light as a huge waste of money. Put another way for the same cost you could have saved many more lives doing other things.

No argument with that (or, rather, what I think you really mean - see next sentence!) - that has been said very many times, both within this formum and in many other places. It's not actually 'Part P' which has been a huge waste of money - 'Part P' is only one sentence, which merely says that domestic electrical work should be done reasonably safely (so as to avoid injuries to persons and fires) - and no-one can really argue with that. It is the requirement for (and cost of) 'notification' of electrical work which has probably been a waste of resources/money. However, sanity has now been partially restored, in that a large part of the requirement for notification disappeared with the changes a couple of months ago.

That said there are a lot of electrical fires, and while few cause any deaths it should give a clue as to where the risk lies. Again it mostly appears to be in appliances so Part P will have had little to no effect anyway.

Again, exactly - no argument about that. However, in terms of the detail, don't forget that many of that 'lot' of electrical fires were probably very minor ones, which did relatively little damge, and certainly caused no injury, and also that 'electrical' is often a scapegoat used to describe the cause of a fire when no other cause can be identified - so one has to to view the figures with some caution.

Kind Regards, John

 

[mfarrow]

In any event, don't forget that there is still going to be the requirement to satisfy the disconnection times in the event of (L-N) 'faults', per 434 - since an RCD will not help in that situation (whether TT or TN). Hence RCDs could never be looked at as opening the floodgates to circuits with R1+R2 which were far too high to get required (L-E) disconnection times

434 doesn't add too much of a restriction, but it does get a bit tight for some circuits when you're out of the magnetic part of the MCB.

 

[JohnW2]

434 doesn't add too much of a restriction, but it does get a bit tight for some circuits when you're out of the magnetic part of the MCB.

One obviously has to do the sums in each case but, unless PSSC was very low, I doubt that one would often be able to comply with 434 if one was 'out of the magnetic part of the MCB' (corresponding to a disconnection time greater than about 11-12 seconds for a Type B MCB).

Kind Regards, John

 

[ban-all-sheds]

Higher rates of death and injury I would imagine is the main difference.

Except, of course, there aren't.

You really do seem to be very non-evidentially biased.

 

[ban-all-sheds]

That said there are a lot of electrical fires, and while few cause any deaths it should give a clue as to where the risk lies.

One risk lies in trying to make policies or promote ideas based on data which comes from Fire Services who do not like (cannot?) to put "unknown" as cause of fire, and therefore put down "electrical" when it's actually unknown.

Even the suspect data you've been banging on about shows that the vast majority of incidents are nothing to do with fixed wiring, so WOE you have been banging on about it as if it were relevant to ring finals and fused plugs is beyond me.

Imagine if we had never had ring finals, and in 2013 you put forward the idea that we could have circuits wired in cable too small for the OPD, and that as long as it was in a ring, and as long as we told people to ensure that the loads were fairly well balanced, and as long as we told people not to have unfused branches of more than one socket, and as long as we introduced fused plugs and as long as we told people to not use the wrong fuse rating in them, it would all be perfectly safe, safer, in fact than 15/16A radials.

I am 100% convinced that there would not be an electrician in the land who would agree with you.