+John Ward after some further digging it turns out this most likely dates 1960s as there is a patent registered for 'Improvements relating to an electrical plug or socket connector', along with a nice technical drawing of the mechanism by MK Electric filed for in 1962 and being granted in 1967 - GB1067870 (A) if you're interested!
The sleeved pins were a patented feature of the MK Safetyplug which came in around 1972 with white sleeves, not black as with later iterations. I've never seen the spring-loaded one before.
I think the last MK springed plug is quite a novel design, albeit flawed in that the sleeving is non permanent. I think these are now made in Malaysia with a different screw terminal design; the modern ones are all standard K646WHI, but I'm not sure whether custom logos are possible now, you can still get Hospital Property toughplugs though!
I'm just about old enough to remember UK plugs and sockets having round pins and no fuses ............. they were just called 5 amp plugs in those days. (looks round for walking stick? now where do I live .............. I forget) :-)
Interesting, I have never seen one of those ‘sprung’ pin covers before (although have seen the switched version). MK plugs are set apart from anything else as you have to coil the wire around the terminal when wiring them up. Much like the Logic range of fused connection units (71-96).
MK made this particular plug for the BBC, they were very common at TVC and BCH usually black but they were also supplied to the BBC in red, green, blue and yellow as well. The BBC variety all had colour coded shrouds on the pins. The plug with the arrow on it may be MOD issue?
The symbol is indeed the "broad arrow" indicating government property in use since at least the 15th century, slightly pre-dating electric plugs. :) en.wikipedia.org/wiki/Broad_arrow
It was used to check if the earth wire was connected or not without opening the plug. Older versions of the standard (BS1363) required this, but that requirement was deleted many years ago so newer plugs do not have it.
Am I correct in saying that the later ones were marketed as MK Safety Plugs? By far the best plug for high amperage applications for things like tumble dryers etc.
Oh wow, plugs-a-matic. :D Some of these plugs feature in my PLUGS PLAYLIST, and you know, there's a couple here that I don't have. I do have one of the Granada plugs though, but it's a bit more scratched-up than this, and not too good of a condition. The brown plug with the Amperage Indicator.....Never seen that one, but I do have an identical plug to this without the facility for the amperage indicator on the back of it. The plug with the retractable sleeving..... That's just Mega drool. :D I have never seen or known of that one, and it looks like its in an unused condition as well! Please be careful with it, that seems like quite a rare one and if dropped.....it'll shatter everywhere! :-O Can I request that you open that plug on-camera so that we can all see inside it and whether the inside differs at all to the more common plug of the same shape? ....I place this vid in my Favourites List because it has some tasty PLUGS in it. :D Thanxx for showing, -BoomBoxDeluxe. _2nd May 2015, 02.40_
Since the late 1980s it has been a legal requirement for all plugs to be manufactured with sleeved pins and for all new appliances to be sold with a plug already fitted. But you can still use unsleeved pin plugs that were already fitted to vintage electrical items. It's arguable weather or not unsleeved pins should still pass a pat test.
Hi @John .. i have a Q plzz .. am using in my AC room type D 15A 220V plug .. now i want to use type B 15A 220V .. is there any way or convener for that ??
Technically no, they would be a fail on a test/inspection and they can't be sold any more. However there are huge numbers still in use and perfectly safe provided you don't shove your fingers between the socket and the plug when removing it.
There's another reason for insulated pins, i have rewritten a story told by a college lecturer to the best of my recollection here sparky-projects.co.uk/pinsulation.html
The symbol on the bottom centre plug looks like an approximation of the MoD pheon or broad arrow applied to government stores. Interestingly, unless correctly applied, it is a criminal offence to use this symbol under the Public Stores Act 1875, S4.
Oh and the chunks missing from the top centre plug were most likely caused by the locator dowels in the bottom half; if you lifted the lid from the top edge, the dowels would snap off taking the corners with them!
Steve Brace Yes, and other government stuff too. Many people assume they're just for Military use, but the GPO tools and equipment were often marked with the broad arrow too (altho interestingly not any of the phones or wiring accessories, mostly tools)
+John Ward after some further digging it turns out this most likely dates 1960s as there is a patent registered for 'Improvements relating to an electrical plug or socket connector', along with a nice technical drawing of the mechanism by MK Electric filed for in 1962 and being granted in 1967 - GB1067870 (A) if you're interested!
I think MK introduced the Safety Plug as we know it today in 1972 - they were certainly the first to market them.
The sleeved pins were a patented feature of the MK Safetyplug which came in around 1972 with white sleeves, not black as with later iterations. I've never seen the spring-loaded one before.
I had something with one of those spring loaded sleeve plugs. I'd forgot all about it. I've also had one with the switch on top.
I think the last MK springed plug is quite a novel design, albeit flawed in that the sleeving is non permanent. I think these are now made in Malaysia with a different screw terminal design; the modern ones are all standard K646WHI, but I'm not sure whether custom logos are possible now, you can still get Hospital Property toughplugs though!
I'm just about old enough to remember UK plugs and sockets having round pins and no fuses ............. they were just called 5 amp plugs in those days.
(looks round for walking stick? now where do I live .............. I forget) :-)
Interesting, I have never seen one of those ‘sprung’ pin covers before (although have seen the switched version).
MK plugs are set apart from anything else as you have to coil the wire around the terminal when wiring them up. Much like the Logic range of fused connection units (71-96).
MK made this particular plug for the BBC, they were very common at TVC and BCH usually black but they were also supplied to the BBC in red, green, blue and yellow as well. The BBC variety all had colour coded shrouds on the pins. The plug with the arrow on it may be MOD issue?
The symbol is indeed the "broad arrow" indicating government property in use since at least the 15th century, slightly pre-dating electric plugs. :)
en.wikipedia.org/wiki/Broad_arrow
Yep, war office crows foot as I always knew it, still a few of these in use across the various MOD sites. I don't think they still issue these
Why do some older plug have that square hold on the top exposing the earth pin ? I have seen loads of older plugs like that.
It was used to check if the earth wire was connected or not without opening the plug. Older versions of the standard (BS1363) required this, but that requirement was deleted many years ago so newer plugs do not have it.
That is interesting, did they get any reason why it was removed , i am guessing so you cannot stick thing in it.
Am I correct in saying that the later ones were marketed as MK Safety Plugs? By far the best plug for high amperage applications for things like tumble dryers etc.
nationalhomecare Yes, later ones have the same wire fixings, similar shape and internal layout.
I wonder how safe those 3 way extension leads they sell at poundland are...
Dan Coster I have seen those, they appear to be glued together as they have no visible screws anywhere.
***** ok
Oh wow, plugs-a-matic. :D Some of these plugs feature in my PLUGS PLAYLIST, and you know, there's a couple here that I don't have.
I do have one of the Granada plugs though, but it's a bit more scratched-up than this, and not too good of a condition.
The brown plug with the Amperage Indicator.....Never seen that one, but I do have an identical plug to this without the facility for the amperage indicator on the back of it.
The plug with the retractable sleeving..... That's just Mega drool. :D I have never seen or known of that one, and it looks like its in an unused condition as well! Please be careful with it, that seems like quite a rare one and if dropped.....it'll shatter everywhere! :-O
Can I request that you open that plug on-camera so that we can all see inside it and whether the inside differs at all to the more common plug of the same shape?
....I place this vid in my Favourites List because it has some tasty PLUGS in it. :D
Thanxx for showing,
-BoomBoxDeluxe.
_2nd May 2015, 02.40_
BoomBoxDeluxe The insides of the plug: ruclips.net/video/oYetrj-wmsg/видео.html
Are the unsleeved pins illegal? I think the 'broad arrow' is MOD
Since the late 1980s it has been a legal requirement for all plugs
to be manufactured with sleeved pins and for all new appliances
to be sold with a plug already fitted. But you can still use unsleeved
pin plugs that were already fitted to vintage electrical items. It's
arguable weather or not unsleeved pins should still pass a pat test.
You have a very interesting channel.
Hi @John .. i have a Q plzz .. am using in my AC room type D 15A 220V plug .. now i want to use type B 15A 220V .. is there any way or convener for that ??
There may be an adaptor, but probably easier to remove the plug and fit a different one.
Are the unsleeved plugs still legal to use?
Technically no, they would be a fail on a test/inspection and they can't be sold any more.
However there are huge numbers still in use and perfectly safe provided you don't shove your fingers between the socket and the plug when removing it.
That actually occured to me while unplugging a christmas light timer yesterday. Fornunatly in Canada it's only 120 volts 15 amps.
There's another reason for insulated pins, i have rewritten a story told by a college lecturer to the best of my recollection here sparky-projects.co.uk/pinsulation.html
***** Yes, that dangerous procedure involving the 13A plug and a 1p coin. Not sure if the story is true or not, however the 1p coin is a perfect fit.
***** I think because it was at a time before sleeved pins were introduced that the coin may have been a sixpence or 1/2 d
The symbol on the bottom centre plug looks like an approximation of the MoD pheon or broad arrow applied to government stores. Interestingly, unless correctly applied, it is a criminal offence to use this symbol under the Public Stores Act 1875, S4.
Oh and the chunks missing from the top centre plug were most likely caused by the locator dowels in the bottom half; if you lifted the lid from the top edge, the dowels would snap off taking the corners with them!
Steve Brace It is, and is colloquially referred to as the 'crows foot'. We used to have them on all our equipment.
Steve Brace Yes, and other government stuff too. Many people assume they're just for Military use, but the GPO tools and equipment were often marked with the broad arrow too (altho interestingly not any of the phones or wiring accessories, mostly tools)