Two extension leads isn't unrealistic, it would be easy to see someone using two in a double rather than cascading them if they need a few sockets. You wouldn't cascade then so why would others?
The socket is a part of the circuit so if you claim it would be a smoking mess then you obviously believe the protection is inadequate despite your arguments that say otherwise.
How would you know, who actually checks?
Don't be such an asshole. You know perfectly well there used to be two sockets allowed on a spur and that they changed it to one because idiot electricians (and others) used to take the socket off, see two cables and decide it was a part of a ring and wire in a new spur. I have seen it, lots of electricians will have seen it and I have said so it previous posts.
If you want to know why a technical committee issues a change you had better ask them, they frequently do it for reasons that make no sense.
Anyway they don't need to make a change, it just requires installers not to do it!
Also wasn't there a major design flaw in aircraft with square windows (comet?) that grounded all models and saw the end of the firm? Remember watching a discovery channel programme about it. It why no planes have square windows now.
The Mark One Comet had square windows, which caused major problems. The Mark Two and Mark Three had round windows, but by the time they were in the air, the Boeing 707 had captured the market.
A later version, the Mark Four was the basis of the Nimrod Search and Rescue aircraft, and is still (Just about) in service, according to the RAF.
Well that text seems to have come from Wikipedia, and there's a link to ^ D.W.M. Latimer: History of the 13 amp plug and the ring circuit. Presentation papers from a public meeting to discuss the issue of ring circuits, IET, London, October 2007 (PDF in ZIP)
It seems that this was incorporated into a supplement to the 11th edition regulations. Presumably double sockets were introduced later, and the rule was clarified from "two sockets" to "two single sockets or one double socket". I can't seem to find any definate date for the change to "one single or one double",
Mike
I am beginning to see how you acquired your reputation here. Writing complete crap. The Chartered Engineers at the IET do know what they are doing with the wiring regulations regardless of your opinion.
I ask again: How many houses have burnt down due to 40A, or more, being drawn though a properly constructed spur? I would be surprised if you could find one over a period of over 60 years.
Indeed, but it seems it rarely happens in practice, even in properties with a single ring covering the whole house.
How many cups of tea does a household make in a row? I sometimes use 3 x kettles for the washing-up and pasta in fairly quick succession and that would be fairly high use.
Usually on own circuit.
1200W mine is. Probably on a 50% duty cycle.
The worst scenario is probably not kitchen appliances, but a group of young women hair-blowing and hair-straightening and frock-ironing preparatory to a night out on the ran-dan.
Most places I've lived have only had 1 x 30A ring for the whole house and it's never gone pop.
Owain
2 singles on a spur allowed under 14th Ed, not allowed under 15th Ed, IIRC.
Owain
Wait until he gets started on geography:-)
Ever been to an Asian wedding? Lights, electric heaters, music, cooking all in a tent running off extension leads, last about three days.
The two leads are not the unrealistic bit. I have frequently use a pair of 4 or even 6 way leads connected to a double socket. In fact looking in my office I probably have 30 odd sockets all running from a single
13A socket. (it feeds a short two way extension lead, that feeds a pair of UPSs, they then each feed multiple 4 and 6 way sockets). Total load can push 500W at times.The unrealistic bit, is finding a 40A of non diverse load to plug into them. That's 40A of load split exactly 20/20 so as not to blow either plug fuse. Multiway leads tend to be mostly 1 - 3m in length - so that is 40A of load probably all in one room. If I turn on every plugged in appliance in my house, it does not come close to 40A on any of the general purpose socket circuits. Even all the kitchen appliances can't manage that for any relevant duration.
That seems to be a meaningless statement. The fate of the socket would be exactly the same on a 32A radial, so the circuit topology is actually irrelevant. The socket is not designed for that load. Live with it.
It also illustrates yet more ways in which your contrived argument is specious. A 40A load would exceed the continuous rating for a single
4mm^2 cable as well, yet I don't hear you bleating about 4mm^2 radials.A long duration 28A load on a 20A radial would be open to the same argument. As has already been pointed out to you several times now, it is the responsibility of the designer, and not the user to mitigate against any potential issue of this nature.
What that the circuit does not spontaneously combust? That hardly needs answering.
That the cables etc are in satisfactory order? The army of electricians carrying out PIRs all round the country for the last 60 years for starters.
Oh, here is a new squirm... well lets see where this one goes.
Yup, seems a fair hypothesis.
Well firstly the circuit is no longer to design is it. So you are raising yet another specious argument.
However the reality is that very few rings, broken or otherwise, will be loaded to anything like full capacity, and I would wager a figure approaching zero will be at full capacity for extended periods. Many of these broken rings will have the cable buried in plaster, and thus it would be able to deliver its full 27A rated capacity.
So again, a theoretical argument, but not an issue in reality.
;-) or as most likely candidates might describe it to the sparks; "I need sockets for several washing machines and tumble driers in the garage please".
(preferably not wired via the meter!)
Yup, it figures it would have to be quite some time ago. 11th sounds plausible - although that pre-dates BS 1363 itself, so presumably it was a later amendment.
Interesting question actually. Don't know when the double socket made an appearance, and if that was significantly after the single.
BS1363-2:1995 makes no explicit mention of double sockets, so not much clue there.
AISI you are squirming, you just can't show that its safe to protect a 2.5 mm cable with a 32A breaker/30A fuse. Sure you can come up with a set of rules that if they are obeyed by the user it will be safe(ish).
I would rather they didn't need the rules as most people don't know there are any.
Here we are again, "it doesn't matter as it isn't to design". Well anything faulty isn't to design. However you design stuff to be safe when they fail where possible, like fitting fuses. You certainly don't design stuff to fail into a dangerous state unless you are pretty dumb. Its also a good idea that it fails in a way that can be detected, by the user is also a good idea.
Its the same argument, cable too small/breaker too big.
I do like how you can gamble with other peoples lives in such a casual way.
Correct but, more fundamentally, mandatory in the 11th - 14th and only guidance the 15th and subsequent editions.
I suspect it was. Doubles were around by the late 50s or early 60s, I think.
There is mention of *twin* socket-outlets though :~).
Dennis; with regards peoples safety using electricity, there are things worth being worried about and things not. Your pet hobby horse has been demonstrated over many years to be a non issue. As time progresses it is becoming even less important.
If you want to rant and rave about stuff that might make a difference, focus on lack of RCD protection, or ageing installations, and installations with too few sockets (promoting trailing leads and hence greater trip hazards), inadequate lighting etc.
The *vast* majority of accidents and injuries that occur with electricity in this country result from (typically improper) use of appliances. Those resulting from failures of fixed installations are vanishingly small.
If you wish to oversize every cable, undersized every MCB because it makes you feel safer, then by all means do it in your own home. Only realise that if you are going to promote this obsession to others, it may well be adopted by some at the expense or them failing to make more worthwhile improvements like ensuring adequate RCD protection is in place. This to me shows a far greater disregard to people's safety, than that exhibited by the rest of us promoting tried and trusted solutions, that are fully in accordance with our extensive and detailed wiring regulations.
Well spotted, so there is ;-)
Only three references though (and mostly content free ones it has to be said)
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