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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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4th Jun 2018, 9:37 am | #101 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
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Re: 13A Twin sockets.
@ Skywave
"Experience is a bad teacher. Gives you the exam first; the lessons come afterwards." What a brilliant way of putting it! Go to the top of the class! I'm going to write that down for posterity! Mike |
4th Jun 2018, 10:06 am | #102 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
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Re: 13A Twin sockets.
@ Hannahs Radios - "I wonder why manufacturers don't simply uprate the internal busbars so that you can,"
And if MK design for 20A-ish, then why not for 26A? Perhaps the cable receptacles/screws would have to be uprated too, and the contact area/riveting between them and the busbars. Perhaps the design was so tight to get the outlets (and two switches) into a space that's less than 2x single sockets that these improvements would have pushed it over the edge on size. Perhaps we'll never know! Last edited by Boulevardier; 4th Jun 2018 at 10:13 am. |
4th Jun 2018, 4:23 pm | #103 |
Heptode
Join Date: Apr 2011
Location: Edinburgh, UK.
Posts: 805
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Re: 13A Twin sockets.
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4th Jun 2018, 5:16 pm | #104 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
Posts: 1,559
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Re: 13A Twin sockets.
I don`t remember double sockets even existing in the early days of 13A ring mains - one single socket in each room whether you needed it or not - and in the most inconvenient place as well.
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4th Jun 2018, 5:38 pm | #105 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 823
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Re: 13A Twin sockets.
Quote:
One prime example is the Philippine Islands, where it seems that no electrical code is adhered to. The mains voltage was increased to 240 volts to increase capacity. Their wiring practices are very crude, at best. |
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4th Jun 2018, 8:03 pm | #106 |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
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Re: 13A Twin sockets.
In Metro-manilla area of Phillipines they have a bi phase supply with 115 volts either side of earth to give 230 volts supply. I agree wiring standards are a bit suspect in that part of the world. Because RCDs are almost unknown there it known for people with US appliances to connect a wire to the metal water pipe and the other to one leg of the supply thereby avoiding the need for a transformer. Check out gadget addict channel on YouTube some of his earlier videos show some of the wiring used there
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4th Jun 2018, 8:43 pm | #107 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,817
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Re: 13A Twin sockets.
SNAP Barry p212*. [My post 9*-Ring Main but not many sockets 1958]. In fact we were on Kerosene lamps in this brand new house on the first night-no power
Someone had nailed through the ring cable When the electrician came the next day he replace the distribution box as one fuse holder was burnt out. He gave it to me as I was so interested in his Megger Testing for the short. A couple of years later, I wired the Box Room [no sockets] to replace power tapped of the light circuit 30's style that I worked from. I wired it to feed my bench through 5 amp fuses [from a socket] as the RSGB Handbook recommended an emergency switch that the family should know about, in case I fried myself. The one socket in the lounge was a bit dodgy so the electrician came back and fitted a marvellous new double socket. We were in awe off as we didn't know they existed. Having moved from a terraced house we only knew single bakelite sockets and adaptors! Dave W Last edited by dave walsh; 4th Jun 2018 at 8:50 pm. |
5th Jun 2018, 5:30 pm | #108 | |
Heptode
Join Date: Mar 2017
Location: Cedar Grove, Wisconsin, USA.
Posts: 823
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Re: 13A Twin sockets.
Quote:
Ring circuits are not allowed in the US and other countries. |
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5th Jun 2018, 6:49 pm | #109 |
Octode
Join Date: Mar 2006
Location: Co. Durham, UK.
Posts: 1,117
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Re: 13A Twin sockets.
If ring circuits had been fused at 15 Amps at each end, rather than 30 Amps before the ring, then they would still be safe even if the ring parted.
I suppose the cost of the extra fuseways was taken into account, the whole thing being a safety/economy compromise. |
5th Jun 2018, 9:08 pm | #110 | |
Heptode
Join Date: Apr 2011
Location: Edinburgh, UK.
Posts: 805
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Re: 13A Twin sockets.
Quote:
http://www.sparkyfacts.co.uk/Inspect...it-Testing.php |
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6th Jun 2018, 8:15 am | #111 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,853
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Re: 13A Twin sockets.
Very useful link, thank you!
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6th Jun 2018, 1:04 pm | #112 | |
Rest in Peace
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
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Re: 13A Twin sockets.
Quote:
Al. |
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6th Jun 2018, 1:11 pm | #113 |
Banned
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Location: Middlewich, Cheshire, UK. & Winter in the Philippines.
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Re: 13A Twin sockets.
NO! A terrible idea, not allowed. It is dangerous to feed any circuit from 2 sources as there is no way to guarantee disconnection.
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6th Jun 2018, 1:31 pm | #114 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
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Re: 13A Twin sockets.
Also, at the danger of expanding slightly beyond the core thread topic (I won't do it again, mods!), the following (from the IEE;s "A Practical Guide to the Wiring Regulations") is worrying -
"..for example, for a 30 A circuit protected by a 30 A rewirable fuse and drawing an overload current of 60 A, disconnection on overload may take up to 4 h. Clearly, this phenomenon needs to be taken into account and this is done by the application of the 0.725 factor as a multiplier to the current-carrying capacity of the circuit cable. One effect of using a rewirable fuse to BS 3036, therefore, is to increase the required cable cross-sectional area for a given load, other parameters being equal." Perhaps there's something in that I'm not fully understanding...? Mike |
6th Jun 2018, 1:38 pm | #115 |
Octode
Join Date: Dec 2017
Location: Morden, Surrey, UK.
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Re: 13A Twin sockets.
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6th Jun 2018, 2:11 pm | #116 |
Dekatron
Join Date: Jan 2006
Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,817
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Re: 13A Twin sockets.
Oh dear but surely that's total incompetence not just breaching the regs?
I was interested in Brigham's post and didn't spot the obvious flaw, although I'm sure I do have a book somewhere that illustrates a separate 15amp fuse each way. I might even have seen a box wired in that manner. Going back to the [I think less concerning safety wise ] double socket and whether there is enough amperage available, I mentioned my assumption that there was 20amps each way [see post 81* and before]. In the recent thread about classic speaker cables, someone mentioned using 7/029 t+e cable [the sort of thing I used to wire with but I have never been a professional "spark"]. The comment was that ring main cable was often utilised for this but the modern stuff was less flexible [and maybe lower rated?] Perhaps this is why my mentor said 7/029 could carry 20 amps back then? I still don't think it's a problem though, either way. Dave |
6th Jun 2018, 2:20 pm | #117 |
Octode
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 1,657
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Re: 13A Twin sockets.
@ Dave Walsh
"In the recent thread about classic speaker cables, someone mentions the previous use of 7/029 t+e cables" I seem to remember that Douglas Self somewhere mentions the use of 2.5mm T&E as a cheap and entirely adequate speaker cable. Hope I'm not "mis-remembering" him! Admittedly, you'd be wasting an earth core.. Mike |
6th Jun 2018, 2:35 pm | #118 | |
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Re: 13A Twin sockets.
Quote:
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6th Jun 2018, 3:04 pm | #119 | |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
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Re: 13A Twin sockets.
Quote:
Could you perhaps be confusing things with the old DC mains where both L and N were fused? I did come across some legacy installations [old 1940s/1950s metalclad fuseboxes with ceramic rewireable fuses] that had live-and-neutral fusing on circuits feeding 5/15A BS546-type outlets but they were installations originally put in place for DC mains. |
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6th Jun 2018, 4:15 pm | #120 |
Dekatron
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Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex.
Posts: 5,817
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Re: 13A Twin sockets.
That's certainly a possibility Tanuki as I do have a few old electrical engineering books. I've only ever used the single feed point myself though when putting in a ring! That air conditioner job seemed like someone who just couldn't be bothered to run a suitable cable from the right source.
Dave Erratum-When I said SNAP [post 107*] I was referring 104* not 212 of course! Last edited by dave walsh; 6th Jun 2018 at 4:30 pm. |