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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 Jul 2011, 8:38 pm | #21 | |||
Octode
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Re: Another unusual plug and some other questions
Hi,
Thanks for the excellent information. Quote:
Quote:
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Regards Andrew |
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2nd Jul 2011, 12:44 pm | #22 |
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Re: Another unusual plug and some other questions
AFAIK Britmac and Dorman & Smith were unrelated at the time although they are now both under the Electrium banner along with Wylex and others (or is it now a Tyco brand?). The Wandsworth plug with automatic switch operation, that I mentioned above, is also unrelated to the DS. It was made by Wandsworth Electrical Ltd and available in the early 30's. Your MK interlocked type is probably mid 20's - early 30's. They are listed in Sunco 1929 but by 1936 MK seem to have been changing to BS gauges for interlocked types. The 15A is then described as having an earth pin 'not grooved or mutilated in any way.'
The non-BS and interlocking types are rare now, I am working on collecting a comprehensive assortment but with some difficulty. The last time I used Wandsworth was in 2002, in an old hall with wiring from the 1920s that had never been inspected or tested since. DS was in use for tech supplies at the BBC until fairly recently. Below are some mobile phone pics of related catalogue pages. Unfortunately I don't have any examples of either type of plug to hand to reveal the constructional details. The sharp-eyed reader will have spotted a mistake in my earlier post where I typed 'Wandsworth gauge' instead of 'Walsall Gauge' when referring to the variant-BS1363 with reversed pin orientations. Lucien |
2nd Jul 2011, 8:43 pm | #23 |
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Re: Another unusual plug and some other questions
While at the workshop earlier I had a look in the unsorted fittings box and found a couple of examples to illustrate these types.
The first picture shows three easily confusable 2-pin plugs: Left: BS 15A (displayed here using the Crater 6-way convertible plug) Centre: MK 15A (the plug from which your 3-pin interlocking one derives) Right: 10A (this example made by Sax) The MK 15A pins lie between the 10A and 15A in diameter and centres. The second picture shows (left) the DS 13A and (right) the Wandsworth, although I can't recall whether this is the 10A or 15A size - the markings are covered up by a strap that won't come off. Lucien |
3rd Jul 2011, 9:15 am | #24 |
Octode
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Re: Another unusual plug and some other questions
Hi,
I have one of the Crater convertible plugs and one of the D&S adapters, identical to those shown in your pictures, in my own collection, along with a couple of different types of D&S plugs. The D&S adapter that I have is simply an adapter but I seem to recall one which, as well as allowing two plugs to be connected, also had connections for a fixed appliance too - i.e. it could be used as a plug in its own right. Apart from the D&S plugs and the MK ones in my original posting, everything else in my collection is to BS gauge. Andrew |
3rd Jul 2011, 1:43 pm | #25 |
Nonode
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Location: Western Lake District, Cumbria (CA20) - UK
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Re: Another unusual plug and some other questions
A colleague of mine worked in the design office of Dorman Smith (no and) and knew the designer of the DS plugs.
Evidently he was quite a perfectionist and it took them such a long time to get the fused version to market that the BS 1363 was firmly ensconced. They were widely used in the new council estates which sprang up before and after WW2, I met them frequently during the 1960s in Huntingdonshire anyway.
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3rd Jul 2011, 1:54 pm | #26 | |
Octode
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Re: Another unusual plug and some other questions
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As an aside I have only ever seen the White/Ivory coloured D&S plugs for sale in Woolworths, but can only ever recall seeing black ones actually in use. Andrew |
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3rd Jul 2011, 4:16 pm | #27 |
Octode
Join Date: Apr 2009
Location: Aylesbury, Buckinghamshire, UK.
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Re: Another unusual plug and some other questions
Since we can assume commercial products are legislation driven, then three pin plugs must have been marketed to satisfy a requirement for an earthing conductor (cpc).
Earthing of electric kettles in kitchens seems a good place to start, does anyone know which edition of the regs this was first mentioned? Rob.
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3rd Jul 2011, 7:57 pm | #28 | ||
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Re: Another unusual plug and some other questions
Quote:
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The critical period for the emergence of 3-pin was during the 20's and 30's. I don't have a copy of the 9th edition of the IEE wiring regs (1927) but in the 10th edition (1934) we find in regulation 1001(E) a requirement to earth all exposed conductive parts of appliances, and a note specifically deprecating the use of reversible 2-pin plugs and lampholder plugs while recommending appliances of all-insulated construction. The implication here is that non-reversible 2-pin plugs would be suitable if such appliances were chosen, and we find reference to the proper connection of non-reversible 2-pin plugs and sockets in 607 (H) and (K). Plugs of this type were available in the era but never caught on, probably due to the lack of all-insulated appliances. Thus, if these regulations were in part responsible for the obsolescence of 2-pin, the lack of polarisation of existing types seems to have been of primary concern. Incidentally, when visualising the wiring of a 3-pin plug in 1934, don't forget that brown was the colour for earth in a flexible, green at that time being one phase of 3-phase AC. Lucien |
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3rd Jul 2011, 8:05 pm | #29 |
Octode
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Re: Another unusual plug and some other questions
Thanks Lucien, a mine of information as ever.
There is a hole in my library between 1910 and 1940 when a lot of changes took place. You talk about non-reversable two pin plugs being acceptable, would this have been with a TNC system (ie. Live and PEN), or insulated items only? I know the 12th edition (1950) mentions single pole fusing, and a permanent connection between neutral and earth as in TNS. It's interesting you suggest that the regs lagged behind the manufacturers. Rob.
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4th Jul 2011, 11:47 am | #30 |
Octode
Join Date: Mar 2011
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Re: Another unusual plug and some other questions
This may be a bit OT and if so I apologise.
This morning I collected a Ferguson 104A radio complete with its original instruction card. This is the same as for the 104U and says that if, when connected to a DC supply, nothing happens after a reasonable warming-up period to reverse the plug. It also suggests doing this on AC to reduce hum. This set came out in 1940 and Ferguson seem to have been taking 2-pin or lamp-holder plugs as the norm then. - Joe |
4th Jul 2011, 5:34 pm | #31 |
Dekatron
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Re: Another unusual plug and some other questions
Hi,
The instruction leaflet for my KB radiogram actually recommended cutting the earth lead off if it was to be fitted with a two pin plug! Those were the days, eh? Since living here I've seen some odd specimens of French plugs & sockets. I'll try and post a few. Cheers, Pete
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7th Jul 2011, 5:02 pm | #32 |
Octode
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Location: Co. Durham, UK.
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Re: Another unusual plug and some other questions
That would be the correct procedure in the circumstances. Leaving the earth lead showing might cause it to come in contact with live metalwork inside the plug, causing the very danger which it is intended to relieve.
I always cut the earth lead off flush with the outer braiding when using 3-core flex in a twin-core situation. It eliminates any possible future confusion. |
10th Jul 2011, 9:45 pm | #33 |
Retired Dormant Member
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Re: Another unusual plug and some other questions
I have an Ever Ready 15 amp plug with three pins on, it looks like a normal plug you can still get but the three pins are round, it does have an earth. Im not sure of its application though because of the amps and those pins, however i have seen those tiny miniture plugs which are triangle in shape an have three round pins. it cost 19p originaly which says it maybe after decimal was switched to £ and P. I have never seen a large three round pin socket to take this plug though.
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11th Jul 2011, 6:22 pm | #34 |
Octode
Join Date: Jul 2006
Location: Willand, Devon, UK.
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Re: Another unusual plug and some other questions
How big is big? 15 amp round pin plugs and sockets are still widely used, size is a bit bigger than a 13A plug with thick round pins. Photos here. Mostly only used for stage lighting these days as they are unfused, chunky and can easily carry the current used in larger stage lights.
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11th Jul 2011, 8:40 pm | #35 | |
Octode
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Re: Another unusual plug and some other questions
Quote:
I don't think that the BS 546 ones were fused but I have seen BS 546 fused plugs made by other manufacturers. I am not sure if I have a 15 amp Ever ready plug in my collection but think I may have a 5 amp one, if/when I find it/them I'll post pictures. Regards Andrew |
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11th Jul 2011, 8:59 pm | #36 |
Octode
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
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Re: Another unusual plug and some other questions
Here you are.
- Joe |
13th Jul 2011, 9:08 pm | #37 |
Pentode
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Location: London, UK.
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Re: Another unusual plug and some other questions
Indeed, 15A BS546 connectors remain the norm for theatre use in the UK, modern exapmles shown below. The main reasons for their continued use being to distinguish between dimmed sipplies and raw mains supplies, and to enable all the fuses or circuit breakers to be in a central location for easier fault finding and repair.
Note that sleeved pins have never become a requirement for these plugs, although a couple of manufacturers have chosen to add that feature. This often raises some eyebrows when it comes to P.A.T. especially in educational environments. However, the production volumes of these connectors are now so low compared to BS1363 that the cost is becomming close to prohibitive and some users are switching to the more common (Europe-wide) BS4343 16A "Ceeform" plug, at less than half the price.
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14th Jul 2011, 4:34 pm | #38 |
Heptode
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Re: Another unusual plug and some other questions
Our house in Acton, West London was wired for the Wylex plugs. We left there in 1981, and it was still the same. The ironmongers at the top of the road kept a drawerful of them and I was always sent up for one to fit on the end of something new. There must have been a local demand around the roads for them.
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25th Jul 2011, 1:06 pm | #39 |
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Re: Another unusual plug and some other questions
Our old village house was wired with 2-pin sockets. It was advertised in 1938 as being 'fitted with electric light'. Eventually my parents were advised to convert to 3-pin (still 5 amp) as it would be safer. We did so. On looking later I discovered the separate new earth wire from the sockets ran to somewhere just under the floor- where it ended! Incidentally to this story, the mains supply was DC from the local mill which was powered by turbines. Generated at 270 volts in order to charge a room full of lead acid batteries to 250 volts, it gave varying voltage to the village according to the time of day-or night- and how far you lived from the mill. The local shop would always ask where you lived when you bought a light bulb, and it was advisable not to use it in the early hours when the batteries were charging and the voltage drop in the overhead wires was low! (One useful aspect of DC was the ability to charge the radio 2v accumulator by running the house supply through it, with dire warning to parents not to use more than a 100w anywhere in the house. That worked until the meter reader found out, and as he also ran the radio battery charging station he wasn't at all happy).
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25th Jul 2011, 10:50 pm | #40 | ||
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Re: Another unusual plug and some other questions
Quote:
Quote:
Lucien |
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