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Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details. |
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1st Jun 2018, 10:08 am | #41 |
Heptode
Join Date: Jul 2012
Location: Bromley, London, UK.
Posts: 702
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Re: 13A Twin sockets.
Just had a thought (rare in itself), what about triple gang sockets? We have one in the kitchen used by the refrigerator, microwave oven, plus spare. This socket does have a built-in 13 Amp fuse and hence provides some protection against gross over-current draw, but are all of the 3-gang sockets fused?
Mike |
1st Jun 2018, 10:36 am | #42 |
Dekatron
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,549
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Re: 13A Twin sockets.
We have got a fused 3 gang socket in our kitchen too.
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1st Jun 2018, 10:48 am | #43 | |
Rest in Peace
Join Date: Apr 2008
Location: London, UK.
Posts: 2,508
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Re: 13A Twin sockets.
Yes, all 3-gang sockets are fused.
Quote:
As far as whether a socket will overheat at 26A, I would suggest we search for empirical evidence that an actual problem exists with this. They don't, even though the manufacturers may only give a 20A rating. Socket terminals only overheat if the termination is not properly executed, and then they might overheat at a mere 10A. What makes the rating 20A anyway? You can get a terminal that one approval rates at 20A and another rates at 32A according to their specific test methods. The current it will endure in practice depends on so many factors; cable gauge, screw tightness, ambient temp, rate of thermal cycling (a terminal loaded to 20A for 5 minutes in every 10 may fail sooner than one loaded to 26A permanently). By comparison, 45A shower switch terminals, manufactured, rated and approved for 45A, overheat and burn out regularly at 40A. I have no figures but would venture 1000 times as frequently as socket-outlet terminals. That's an actual problem, whereas the socket is a theoretical one. And as per the tests mentioned above, plugs and especially fuse clips overheating at 13A is a real problem. Moving on to the more fundamental subject of how a device may be legitimately constructed in such a way as it can be pushed outside its approved envelope and operated in a dangerous way, without automatic protection taking over, I would suggest comparison with a car! |
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1st Jun 2018, 10:50 am | #44 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,951
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Re: 13A Twin sockets.
I can't help feel there's a touch of obsessive paranoia revealed in this thread: OK, you *can* overload a dual-13A socket, but IMHO you'd be more likely to overload a 'ring' by having multiple 3Kw loads on the same ring but in different rooms.
The evidence from fire-service statistics is that over the last decade domestic fires have fallen significantly, continuing a trend that was established quite some time back. See https://www.ukfiretraining.com/news/...downwards.html This is despite the increase in number of things like 'wall-warts' and other stuff that's left powered 24x7 (microwaves, TVs, PVRs, set-top-boxes, internet routers and the like). I don't see 'you can take 26A from a dual 13A socket' as being anything for normal people to get their underwear in any kind of knot over: the additional stress caused by worrying unnecessarily about such very-low-probability events is probably more likely to kill you than the event itself! |
1st Jun 2018, 11:51 am | #45 |
Heptode
Join Date: May 2009
Location: Birmingham, West Midlands, UK.
Posts: 708
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Re: 13A Twin sockets.
Apparently it was not an overloaded wall socket that was the start of the recent tragic tower block fire, where despite the block having a refit a few years ago (where presumbly RCDs etc and smoke alarms were replaced or installed) a low current draw item - the fridge- was the culprit, which obviously didn't trip anything and despite the early signs of a problem-smells,smoke etc was allowed to get to a stage where it was a full blown fire lapping out of the windows and consequently igniting the cladding and the terrible tragedy that followed.
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1st Jun 2018, 12:14 pm | #46 |
Dekatron
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Re: 13A Twin sockets.
Indeed a recent thread highlighted Tumble Dryers and other white goods as a really major ongoing concern, however the power is supplied to the appliance via a ring or other circuit.
Dave W |
1st Jun 2018, 12:19 pm | #47 | |
Moderator
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Re: 13A Twin sockets.
Quote:
Back on topic please.
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1st Jun 2018, 1:13 pm | #48 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 1,641
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Re: 13A Twin sockets.
G6Tanuki - "I can't help feel there's a touch of obsessive paranoia revealed in this thread: OK, you *can* overload a dual-13A socket, but IMHO you'd be more likely to overload a 'ring' by having multiple 3Kw loads on the same ring but in different rooms."
True, but there's a critical difference - if you overload the ring you're protected by the 30A fuse which will disconnect the ring. If you overload a twin socket the fuse won't blow until/unless you draw more than 30A, but you could still be pulling 29.9A through the socket with it merrily melting without blowing fuse! Not sure I'd call worrying about this "paranoia" - more like common-sense safety. The regulatory system forces us to obsess about earth-loop impedance, sleeving on earth wires, etc, but doesn't seem to have too much concern about a basic issue like this. All rather strange... ! Mike |
1st Jun 2018, 1:22 pm | #49 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
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Re: 13A Twin sockets.
I`d be interested to know how many fires have been caused by an overloaded 13A twin socket compared with the number caused by a single 13A plug running within its rating but with loose connections and or loose fitting fuses.
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1st Jun 2018, 1:56 pm | #50 | |
Octode
Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
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Re: 13A Twin sockets.
Quote:
"2 Gang Switchsocket Outlet with Integrated Dual USB Charging Capability TECHNICAL SPECIFICATION 13A SOCKET OUTLETS ELECTRICAL VOLTAGE RATING 220-240V CURRENT RATING 13A Combined total 2A drawn from USB outlets" which makes me think that each outlet is capable of 13A. John |
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1st Jun 2018, 2:15 pm | #51 | |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,427
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Re: 13A Twin sockets.
Quote:
Sensible observation of plugs and sockets without being paranoid about it is all I do, most of us wouldn’t leave a dripping tap or a leaking windows long before fixing it, same with electrical items.
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Frank |
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1st Jun 2018, 2:21 pm | #52 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 1,641
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Re: 13A Twin sockets.
@ John MOGLN - "doing a search on a number of websites I can't find anything to the contrary"
Here's an example of discussions of the issue on an IET forum - https://www.theiet.org/forums/forum/...threadid=33787 |
1st Jun 2018, 3:54 pm | #53 |
Octode
Join Date: Jan 2004
Location: Southport, Merseyside, UK.
Posts: 1,156
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Re: 13A Twin sockets.
Thanks for the link, I had no doubt that there would be discussions somewhere but these are not going to be seen by the vast majority of the population who will be using 13A plugs, the MK two gang sockets described in their 'Wiring Devices Technical' file have 4 references to the current supply capability of the USB sockets but strangely none regarding the 13A sockets except that they are 13A.
John |
1st Jun 2018, 4:23 pm | #54 |
Retired Dormant Member
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Location: Shropshire, UK.
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Re: 13A Twin sockets.
Interesting that the times quoted in MK's own stress tests are inconsistent with the assumed conditions for thermal stability in the official test.
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1st Jun 2018, 4:40 pm | #55 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 1,641
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Re: 13A Twin sockets.
@ John MOGLN - Also interesting that in that IET link (from 2009) there seemed to be general ignorance of and/or lack of concern about the issue amongst the forumniks (some or many of whom are probably professional electricians). I do wonder how many professionals are aware of it even today... And the same old arguments about "hardly ever going to happen", and "don't worry about it".
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1st Jun 2018, 4:44 pm | #56 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
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Re: 13A Twin sockets.
Q: Can you produce any evidence from a credible source (Fire-service, Home Office, insurance industry) that this 'issue' has ever been attributed as the cause of a fire or significant injury to property or persons?
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1st Jun 2018, 4:53 pm | #57 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 1,641
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Re: 13A Twin sockets.
No, I wouldn't know where to look. And I'm not sure whether such reports provide that level of detail - maybe they just give the cause as generic "electrical fault". Others may know.
But, I keep reminding myself that being able to pull up to 26A out of a 13A-rated unit is fundamentally a "bad idea". And, as I've said, given the detail and rigour of most of the other regulations, the overlooking of this problem is extraordinary. |
1st Jun 2018, 5:19 pm | #58 |
Heptode
Join Date: Apr 2003
Location: Cornwall, UK.
Posts: 985
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Re: 13A Twin sockets.
13 Amp sockets and spurs are designed to comply in the first instance to BS1363. Reference should be made to this standard to find out the design, test and load criteria.
Does anyone on here have access to this document? Perhaps it might give some definitive answers. SimonT .
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1st Jun 2018, 7:59 pm | #59 |
Hexode
Join Date: Oct 2016
Location: Newport, South Wales, UK.
Posts: 278
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Re: 13A Twin sockets.
You can buy a copy for (are you sitting down?) £254
https://shop.bsigroup.com/ProductDet...00000030365274 |
1st Jun 2018, 8:56 pm | #60 |
Heptode
Join Date: Apr 2003
Location: Cornwall, UK.
Posts: 985
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Re: 13A Twin sockets.
...Having to buy the 18th Regs book next month at around £80 is bad enough. I think I’ll give it a miss.
That’s why I was hoping someone here would have access to a copy SimonT.
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