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Connectors - and ring mains
On 09/04/2021 19:07, Clive Page wrote:
I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug.Â* He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper.Â* So someone invented the ring-main which generally used less cable.Â* The problem was that the ring-main fuses had to be larger and so the system wasn't as safe.Â* The solution was to put a fuse in each plug-top and this made them much larger.Â* Does that sound a reasonable explanation? In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less.Â* In North America they don't seem to worry much about safety given their lower mains voltage, but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box?Â* I have never thought to enquire. The ring main certainly saved wire as more and more sockets were fitted. It also gave two paths to each socket - did Hunkin mention that? The 3-pin round-pin domestic plugs were 15A, 5A and 2A, IIRC. Volume-wise the 13A is not that different. The US domestic systems do have 220v capability - so they're not that different from us. PA |
Connectors - and ring mains
On 09/04/2021 19:29, Owain Lastname wrote:
On Friday, 9 April 2021 at 19:07:39 UTC+1, Clive Page wrote: The problem was that the ring-main fuses had to be larger and so the system wasn't as safe. The solution was to put a fuse in each plug-top and this made them much larger. Does that sound a reasonable explanation? Not quite. There is a secondary purpose to the fuse - it limits 13A sockets to 13A max load Good point. Try putting a 13A load on a 13A plug. They get pretty warm even when conditions are optimal! PA |
Connectors - and ring mains
I just watched another of Tim Hunkin's excellent videos - this one is on connectors:
https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug. He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper. So someone invented the ring-main which generally used less cable. The problem was that the ring-main fuses had to be larger and so the system wasn't as safe. The solution was to put a fuse in each plug-top and this made them much larger. Does that sound a reasonable explanation? In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. In North America they don't seem to worry much about safety given their lower mains voltage, but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box? I have never thought to enquire. -- Clive Page |
Connectors - and ring mains
On 09/04/2021 19:07, Clive Page wrote:
In North America they don't seem to worry much about safety given their lower mains voltage, But lower voltage means higher current for the same use. So they have proportionally more house fires, due to failing connections carrying that much higher current, combined with the US favouring timber frame construction rather than bricks and mortar, compared to UK -- Global sea level rise to 2100 from curve-fitted existing altimetry data http://diverse.4mg.com/slr.htm |
Connectors - and ring mains
On 09/04/2021 19:07, Clive Page wrote:
I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug.Â* He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper.Â* So someone invented the ring-main which generally used less cable.Â* The problem was that the ring-main fuses had to be larger and so the system wasn't as safe.Â* The solution was to put a fuse in each plug-top and this made them much larger.Â* Does that sound a reasonable explanation? In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less.Â* In North America they don't seem to worry much about safety given their lower mains voltage, but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box?Â* I have never thought to enquire. A bit slack with the past and present tenses. 8 min 46 sec "so it was extremely safe" -- Adam |
Connectors - and ring mains
On 09/04/2021 18:45, Peter Able wrote:
On 09/04/2021 19:07, Clive Page wrote: I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug.Â* He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper. So someone invented the ring-main which generally used less cable. The problem was that the ring-main fuses had to be larger and so the system wasn't as safe.Â* The solution was to put a fuse in each plug-top and this made them much larger.Â* Does that sound a reasonable explanation? In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less.Â* In North America they don't seem to worry much about safety given their lower mains voltage, but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box?Â* I have never thought to enquire. The ring main certainly saved wire as more and more sockets were fitted. It also gave two paths to each socket - did Hunkin mention that? The 3-pin round-pin domestic plugs were 15A, 5A and 2A, IIRC. Volume-wise the 13A is not that different. The US domestic systems do have 220v capability - so they're not that different from us. From a pedantic POV, the USA has 120V between live and neutral. It can also have 240V or 208V depending on the supply. 208V being from 2 legs of their 3-phase supply. |
Connectors - and ring mains
On 09/04/2021 19:07, Clive Page wrote:
In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Bill |
Connectors - and ring mains
Fredxx wrote:
From a pedantic POV, the USA has 120V between live and neutral. It can also have 240V or 208V depending on the supply. 208V being from 2 legs of their 3-phase supply. Not wuite, they have 3-phases in the street but their transformers (pole pigs) have centre tapped secondary so it gives +110V/N/-110V to the house, most circuits use a single live (hot) to neutral, but heavy duty stuff like tumble driers use both hots https://youtu.be/jMmUoZh3Hq4 |
Connectors - and ring mains
In article ,
williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Bill They are bigger. Still used in theatres. ^^^ -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
Connectors - and ring mains
On 09/04/2021 19:29, Owain Lastname wrote:
There is a secondary purpose to the fuse - it limits 13A sockets to 13A max load, thus reducing high point loads which would unbalance the ring. With unfused plugs a naughty person would be able to plug their cooker into the ring circuit. In the unfused round-pin days there were hosts of adapters allowing table lamps to be plugged into 15A sockets without fusing. For some reason BS1363 doesn't require 2-way adapters to be fused, and used not to require 3-way adapters to be fused either but this has now been changed. I remember when the sockets in the workshop at the place where I worked were converted from 15A to 13A to bring them up to date and make them compatible with more kit. They were still on individual radial circuits rather than a ring. We had a problem with an arc welder which had been fine with an unfused 15A plug but kept blowing fuses in its 13A plug - until some bright spark had the idea of turning up a solid brass "fuse" on the lathe. we didn't have any more problems then! [*And* it was no less safe than the earlier arrangement apart perhaps for the risk that the plug would overheat because square pins into metal strips are nothing like as robust as round pins into close-fitting round tubes.] -- Cheers, Roger |
Connectors - and ring mains
On 09/04/2021 20:26, williamwright wrote:
On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Bill And a lot more robust. -- Cheers, Roger |
Connectors - and ring mains
On 09/04/2021 21:28, charles wrote:
In article , williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Bill They are bigger. Still used in theatres. ^^^ The reason for that is if a plug had a fuse in it and it blew during a live performance, it was not a quick or safe job to get a maintenance man out to climb into the suspended walkways in the dark, find the plug, unplug it, take it apart, replace fuse, reassemble the plug, plug it back in and vacate the suspended walkways. instead, the arrangement was a wall of MCBs or fuses immediately after the lighting power thyristors controlled by the lighting desk. They were on the wall in the same room as the lighting engineer.... so if a circuit pops, the lighting engineer had to reset/replace the MCB/fuse there and then instead. |
Connectors - and ring mains
On 09/04/2021 20:39, Andy Burns wrote:
Fredxx wrote: Â*From a pedantic POV, the USA has 120V between live and neutral. It can also have 240V or 208V depending on the supply. 208V being from 2 legs of their 3-phase supply. Not wuite, they have 3-phases in the street but their transformers (pole pigs) have centre tapped secondary so it gives +110V/N/-110V to the house, most circuits use a single live (hot) to neutral, but heavy duty stuff like tumble driers use both hots https://youtu.be/jMmUoZh3Hq4 1) First all the guy in the video is correct. 2) The voltage is 120V but also 240V or 208V depending on the supply. https://en.wikipedia.org/wiki/Mains_electricity "In the United States[14][15] and Canada,[16] national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 V to 126 V (RMS) (ˆ’5% to +5%). Historically 110 V, 115 V and 117 V have been used at different times and places in North America. Mains power is sometimes spoken of as 110 V; however, 120 V is the nominal voltage." 3) 208V or 240V is supplied to homes. 240V split either side of ground/neutral is the most common but many domestic builds simply supply 2 phases and not every home has it's dedicated transformer. It's obviously cheaper for a one large transformer supply a block of flats and houses. Many appliances will have a 208/220/240V label. I can find very little with Google, but this is an article with an explanation: https://www.researchgate.net/post/Co...r-110-or-220-V Obviously: 208 = sqrt(3) * 120 HTH |
Connectors - and ring mains
In article ,
Roger Mills wrote: On 09/04/2021 19:29, Owain Lastname wrote: There is a secondary purpose to the fuse - it limits 13A sockets to 13A max load, thus reducing high point loads which would unbalance the ring. With unfused plugs a naughty person would be able to plug their cooker into the ring circuit. In the unfused round-pin days there were hosts of adapters allowing table lamps to be plugged into 15A sockets without fusing. For some reason BS1363 doesn't require 2-way adapters to be fused, and used not to require 3-way adapters to be fused either but this has now been changed. I remember when the sockets in the workshop at the place where I worked were converted from 15A to 13A to bring them up to date and make them compatible with more kit. They were still on individual radial circuits rather than a ring. We had a problem with an arc welder which had been fine with an unfused 15A plug but kept blowing fuses in its 13A plug - until some bright spark had the idea of turning up a solid brass "fuse" on the lathe. we didn't have any more problems then! [*And* it was no less safe than the earlier arrangement apart perhaps for the risk that the plug would overheat because square pins into metal strips are nothing like as robust as round pins into close-fitting round tubes.] just cut the correct length off a metal potentiometer spindle. They were the right diameter -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
Connectors - and ring mains
On 09/04/2021 19:07, Clive Page wrote:
I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug.Â* He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper.Â* So someone invented the ring-main which generally used less cable.Â* The problem was that the ring-main fuses had to be larger and so the system wasn't as safe.Â* The solution was to put a fuse in each plug-top and this made them much larger.Â* Does that sound a reasonable explanation? Apart from the fuse making it larger part - Then that is the thrust of it. A ring can serve lots of sockets with less cable and is easier to wire if you need a high power delivery. It could also be cobbled together from two existing 15A radials, and be far more versatile than the sum of the parts. The modern implementation of the ring turning out to be very well suited to modern applications (i.e. loads of sockets and load of small loads) In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. Indeed - if anything they are larger. In North America they don't seem to worry much about safety given their lower mains voltage, They don't but ought to (the number of electrocutions there per year are staggering compared to ours!) but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box?Â* I have never thought to enquire. Most places use lots of radials serving just a few sockets, with the MCB sized to offer both fault and overload protection to all of the circuit, right up to the appliance. (contra you our design where the MCB[1] offers fault and overload protection for the ring circuit as far as the sockets, but the plug fuse extends fault protection up to the inlet of the appliance). [1] in conjunction with some design rules. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
Connectors - and ring mains
"N_Cook" wrote in message ... On 09/04/2021 19:07, Clive Page wrote: In North America they don't seem to worry much about safety given their lower mains voltage, But lower voltage means higher current for the same use. So they have proportionally more house fires, due to failing connections carrying that much higher current, The code system avoids house fires due to electrical faults. combined with the US favouring timber frame construction rather than bricks and mortar, compared to UK Thats the real reason. |
Connectors - and ring mains
"Owain Lastname" wrote in message ... On Friday, 9 April 2021 at 19:07:39 UTC+1, Clive Page wrote: The problem was that the ring-main fuses had to be larger and so the system wasn't as safe. The solution was to put a fuse in each plug-top and this made them much larger. Does that sound a reasonable explanation? Not quite. There were lots of small appliances intended for use on 2A and 5A plugs, with thin flexes. And because there weren't many sockets, a lot of those appliances had long leads. Long, thin leads aren't adequately protected by a 30A fuse, so fused plugs were necessary. Doesnt explain why all other countrys handle those fine without fused plug tops. There is a secondary purpose to the fuse - it limits 13A sockets to 13A max load, thus reducing high point loads which would unbalance the ring. With unfused plugs a naughty person would be able to plug their cooker into the ring circuit. In the unfused round-pin days there were hosts of adapters allowing table lamps to be plugged into 15A sockets without fusing. For some reason BS1363 doesn't require 2-way adapters to be fused, and used not to require 3-way adapters to be fused either but this has now been changed. what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box? I have never thought to enquire. They usually use 16A or 20A radial circuits, and modern appliances have thick (or short) enough flexes that they are adequately protected by a 20A MCB. Thats wrong with the flex claim. |
Connectors - and ring mains
On 09/04/2021 23:04, charles wrote:
In article , Roger Mills wrote: On 09/04/2021 19:29, Owain Lastname wrote: There is a secondary purpose to the fuse - it limits 13A sockets to 13A max load, thus reducing high point loads which would unbalance the ring. With unfused plugs a naughty person would be able to plug their cooker into the ring circuit. In the unfused round-pin days there were hosts of adapters allowing table lamps to be plugged into 15A sockets without fusing. For some reason BS1363 doesn't require 2-way adapters to be fused, and used not to require 3-way adapters to be fused either but this has now been changed. I remember when the sockets in the workshop at the place where I worked were converted from 15A to 13A to bring them up to date and make them compatible with more kit. They were still on individual radial circuits rather than a ring. We had a problem with an arc welder which had been fine with an unfused 15A plug but kept blowing fuses in its 13A plug - until some bright spark had the idea of turning up a solid brass "fuse" on the lathe. we didn't have any more problems then! [*And* it was no less safe than the earlier arrangement apart perhaps for the risk that the plug would overheat because square pins into metal strips are nothing like as robust as round pins into close-fitting round tubes.] just cut the correct length off a metal potentiometer spindle. They were the right diameter I've seen a piece from a 1/4 Whit bolt used. Of course the usual thing is to wrap silver paper from a fag packet round the blown fuse. Incidentally the 15A plugs in my first house used to get very hot. Bill |
Connectors - and ring mains
On 09/04/2021 21:28, charles wrote:
They were bigger. Bill They are bigger. Still used in theatres. ^^^ You wouldn't want to be climbing up into the lighting gantry at the interval to change a fuse. Bill |
Connectors - and ring mains
On 10/04/2021 01:04, John Rumm wrote:
In North America they don't seem to worry much about safety given their lower mains voltage, They don't but ought to (the number of electrocutions there per year are staggering compared to ours!) Not all of them accidental. Bill |
Connectors - and ring mains
On Sat, 10 Apr 2021 01:04:28 +0100, John Rumm wrote:
On 09/04/2021 19:07, Clive Page wrote: I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug.Â* He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper.Â* So someone invented the ring-main which generally used less cable.Â* The problem was that the ring-main fuses had to be larger and so the system wasn't as safe.Â* The solution was to put a fuse in each plug-top and this made them much larger.Â* Does that sound a reasonable explanation? Apart from the fuse making it larger part - Then that is the thrust of it. A ring can serve lots of sockets with less cable and is easier to wire if you need a high power delivery. It could also be cobbled together from two existing 15A radials, and be far more versatile than the sum of the parts. The modern implementation of the ring turning out to be very well suited to modern applications (i.e. loads of sockets and load of small loads) In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. Indeed - if anything they are larger. In North America they don't seem to worry much about safety given their lower mains voltage, They don't but ought to (the number of electrocutions there per year are staggering compared to ours!) but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box?Â* I have never thought to enquire. Most places use lots of radials serving just a few sockets, with the MCB sized to offer both fault and overload protection to all of the circuit, right up to the appliance. (contra you our design where the MCB[1] offers fault and overload protection for the ring circuit as far as the sockets, but the plug fuse extends fault protection up to the inlet of the appliance). [1] in conjunction with some design rules. When I was young we had DC mains and the cooker control box had fused 15amp and 5 amp round pin sockets. The switches were the two pole rotary type. All my experiments were done, using an ex WD rotary transformer used in reverse, to get ~28volts DC. |
Connectors - and ring mains
williamwright wrote:
On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Chris -- Chris J Dixon Nottingham UK @ChrisJDixon1 Plant amazing Acers. |
Connectors - and ring mains
In article , Chris J Dixon
wrote: williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Chris Yes -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
Connectors - and ring mains
Chris J Dixon formulated the question :
williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Chris Yep, I used to have one, wired to a 13amp socket - in the days when you were faced with a variety of plugs. |
Connectors - and ring mains
Might I just say that although this house was built in 1939, it was built
using 13 amp sockets on the old rubber and fabric covered wires, including earth. I could not say if it was ring main or not, or much else but I can tell you that the lights did not have unstitched lives in the rose. There were also a smattering of 2 pin 5a sockets as well, apparently wired to the one lighting circuit. All the 13 amp sockets were on one circuit. Of course the old consumer unit used wire fuses, and was made of metal. We had the place rewired in the 70s and then we had split upstairs and downstairs circuits, all the sockets were raised up above the skirting and all were on ring mains, but oddly, the bar fires in the bedrooms were on the lighting circuit, not the socket one. In one case it was spurred off the ring though as it was basically an afterthought. Apart from the colours being wrong for today and the old circuit breakers instead of the more sophisticated fault protection of today, its in very good condition still. Brian -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "Clive Page" wrote in message ... I just watched another of Tim Hunkin's excellent videos - this one is on connectors: https://www.youtube.com/watch?v=q43tZ6DjuIE One of the connectors he deals with is the UK 13A power plug. He claims that it was introduced in about 1947 because of the copper shortage. The reasoning is that there was a post-war housing boom - I expect that a lot of existing houses also needed re-wiring - but that the conventional way of doing this by running a cable from the fuse-box to each separate mains socket was deemed wasteful of copper. So someone invented the ring-main which generally used less cable. The problem was that the ring-main fuses had to be larger and so the system wasn't as safe. The solution was to put a fuse in each plug-top and this made them much larger. Does that sound a reasonable explanation? In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. In North America they don't seem to worry much about safety given their lower mains voltage, but what about mainland Europe - do they use ring mains with their fuse-less plugs or does each socket have a separate run back to the fuse-box? I have never thought to enquire. -- Clive Page |
Connectors - and ring mains
On Saturday, 10 April 2021 at 08:32:19 UTC+1, charles wrote:
In article , Chris J Dixon wrote: williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Chris Yes -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle How about these, https://www.plugsocketmuseum.nl/Wylex1.html A flat I moved into in the early seventies had sockets for these, the plugs were a bugger to find. I think the landlord used them deliberately and sold spares to tenants to enable them to cob together leads in order to use standard square pin plugs on personal electrical equipment. I think he limited the number issued so the system could not be overloaded. Richard |
Connectors - and ring mains
In article ,
Tricky Dicky wrote: On Saturday, 10 April 2021 at 08:32:19 UTC+1, charles wrote: In article , Chris J Dixon wrote: williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Chris Yes -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle How about these, https://www.plugsocketmuseum.nl/Wylex1.html A flat I moved into in the early seventies had sockets for these, the plugs were a bugger to find. I think the landlord used them deliberately and sold spares to tenants to enable them to cob together leads in order to use standard square pin plugs on personal electrical equipment. I think he limited the number issued so the system could not be overloaded. They look very much like the ones the NSHEB introduced. The D&S mentioned on that page were adopted at TV Centre for 'technical supplies"; stopped the cleaner plugging in a vacuum cleaner. They were probably used in some mansion blocks in central London since Selfridges used to sell the fuses. -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
Lonely Sociopathic Auto-contradicting Senile Ozzie Troll Alert!
On Sat, 10 Apr 2021 10:26:30 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again: Doesn¢t explain why all other countrys handle those fine without fused plug tops. "Countrys"? Yet again? So, sociopathic swine that you are, you still refuse to adopt the general rules for spelling! Or WHY do you INSIST on sticking to your own personal spelling, sociopath? -- John addressing the senile Australian pest: "You are a complete idiot. But you make me larf. LOL" MID: |
Connectors - and ring mains
Owain Lastname wrote
Rod Speed wrote There were lots of small appliances intended for use on 2A and 5A plugs, with thin flexes. Doesnt explain why all other countrys handle those fine without fused plug tops. 1. Because they didn't have 2A and 5A circuits, their appliances had thicker flexes? No they didnt. 2. Many European countries had bottle fuses which may have provided finer protection than rewireable fuses used in Britain. No they didnt. 3. Their electrical safety standards were/are lower? No they werent/arent. 4. We designed the fused 13A plug to suit the conditions in the UK at the time and to be the best possible solution overall, Thats bull****. albeit a compromise in some ways. All systems always are. |
Connectors - and ring mains
On 10/04/2021 10:24, Owain Lastname wrote:
On Saturday, 10 April 2021 at 01:26:43 UTC+1, Rod Speed wrote: There were lots of small appliances intended for use on 2A and 5A plugs, with thin flexes. Doesnt explain why all other countrys handle those fine without fused plug tops. 1. Because they didn't have 2A and 5A circuits, their appliances had thicker flexes? 2. Many European countries had bottle fuses which may have provided finer protection than rewireable fuses used in Britain. 3. Their electrical safety standards were/are lower? 4. We designed the fused 13A plug to suit the conditions in the UK at the time and to be the best possible solution overall, albeit a compromise in some ways. I would have thought it would be better to have fused sockets, then there wouldn't be the chance of overload with multiple appliances plugged into the socket with an unfused adapter. -- Max Demian |
Connectors - and ring mains
On 10/04/2021 07:56, Chris J Dixon wrote:
williamwright wrote: On 09/04/2021 19:07, Clive Page wrote: In fact I can just recall the old 15 amp 3-pin plugs which preceded them and I don't think they were all that much smaller even though they were fuse-less. They were bigger. Does anyone remember this monstrosity? https://www.plugsocketmuseum.nl/Fitall1.html Yes they were yummy. -- Max Demian |
Connectors - and ring mains
Max Demian wrote:
I would have thought it would be better to have fused sockets, then there wouldn't be the chance of overload with multiple appliances plugged into the socket with an unfused adapter. The circuit breaker (or rewireable fuse) is supposed to protect the house wiring. The plugtop fuse is to protect the appliance wiring. A fused socket can't tell whether you plugged in a 1A appliance or a 13A appliance. If the 1A appliance starts taking 10A its cable may melt, but a 13A fused socket wouldn't notice. By putting a 1A fuse in the plugtop you can protect the appliance's cable. If you're running a multiway extension then that has a fuse in /its/ plugtop which is matched to the maximum current the extension can handle. If you daisy chain extensions, or plug in three kettles, that fuse should blow before troubling the circuit breaker. There shouldn't be unfused adapters, because then you're only relying on the circuit breaker. If you have a removable appliance cable, like a C13 'kettle lead', the same holds if the fuse in the plugtop is rated for the size of the cable - it's fine to fit a 10A fuse on a C13 cable capable of carrying 10A - as long as the appliance has its own fuse (typically at the IEC inlet) rated for its own requirements. Theo |
Connectors - and ring mains
In article ,
SH wrote: They are bigger. Still used in theatres. ^^^ The reason for that is if a plug had a fuse in it and it blew during a live performance, it was not a quick or safe job to get a maintenance man out to climb into the suspended walkways in the dark, find the plug, unplug it, take it apart, replace fuse, reassemble the plug, plug it back in and vacate the suspended walkways. Err, theatre lighting doesn't use a ring main. Most usually a radial with dimmer control. You don't want such circuits confused with a GP mains supply - hence different connectors. -- *Isn't it a bit unnerving that doctors call what they do "practice?" Dave Plowman London SW To e-mail, change noise into sound. |
Connectors - and ring mains
In article ,
Brian Gaff \(Sofa\) wrote: Might I just say that although this house was built in 1939, it was built using 13 amp sockets on the old rubber and fabric covered wires, including earth. Pretty certain 13 amp was a post war thing, Brian. But it could have taken a long time to build your house. ;-) -- *A plateau is a high form of flattery* Dave Plowman London SW To e-mail, change noise into sound. |
Connectors - and ring mains
In article ,
Max Demian wrote: I would have thought it would be better to have fused sockets, then there wouldn't be the chance of overload with multiple appliances plugged into the socket with an unfused adapter. How would the socket know which fuse to fit? Never noticed some appliances come with a 5 amp fuse in the plug? -- *Why is it called tourist season if we can't shoot at them? Dave Plowman London SW To e-mail, change noise into sound. |
Connectors - and ring mains
"Dave Plowman (News)" wrote in message
... In article , SH wrote: They are bigger. Still used in theatres. ^^^ The reason for that is if a plug had a fuse in it and it blew during a live performance, it was not a quick or safe job to get a maintenance man out to climb into the suspended walkways in the dark, find the plug, unplug it, take it apart, replace fuse, reassemble the plug, plug it back in and vacate the suspended walkways. Err, theatre lighting doesn't use a ring main. Most usually a radial with dimmer control. You don't want such circuits confused with a GP mains supply - hence different connectors. Ah, I wasn't sure whether lighting circuits in theatres were spurs (with only one route from the supply to the lamps) or a ring (with two alternative routes from the supply to the lamps). Either way, they are fused at the lighting board rather than the plug, and usually the supply goes via a variable resistor or triac dimmer and switches so several circuits can be switched on/off or dimmed in synchrony. I remember working as a lighting operator for school plays, perched 10 feet above one side of the stage on a gantry with a row of about 10 vertical wire-wound dimmers which could be switched between lighting circuits - eg we'd put all the lights that we wanted to dim in sync on adjacent dimmers so a 2-, 3- or 4-dimmer length of wood could be used to move all the dimmers in sync. Once that effect was over, we'd switch circuits to other dimmers to put ones for another synchronous effect on adjacent dimmers. The fuses were per dimmer rather than per lighting circuit, so if a fuse blew, you switched the circuit to another dimmer while you rewired the blown fuse. I remember the "blackout" switch that killed all lights everywhere when a total instantaneous blackout was needed: it was a surprisingly small insignificant switch which operated a humungous relay nearby which always made a loud clonk. The big daddy dimmer was the one for the house lights. That was a flat box about 3 feet square with load of ventilation holes all over it and a big wheel on the front that made a loud screeching noise as the contacts moved over the wire-wound coil. The instruction there was the move it smoothly, quickly and fully from one end to the other, not leaving it half-on or almost-but-not-quite off/on for any longer than necessary because it got very hot. I think there were 24 house lights, each with a 500 W bulb shaped like a very large 60 W bulb, so that was 12 kW that had to be dimmed - hence the need to go from off to on as quickly as possible, because the wire-wound coil didn't like 12 kW passed through it. The school also had a lecture theatre with a modern triac dimmer system in the projection booth and ceiling-mounted lights. But it had no proscenium arch and no wings, so all the fancy lighting couldn't be used for a stage play where actors had to enter or exit. The only way to do it was to open one of the fire doors either side of the "stage" and have the actors enter from outside in the playground. What intrigued me about the lecture theatre was that the fluorescent tubes could be dimmed from very dim to fully bright - they couldn't dim right to extinction so there was a sudden switch-off once they got very dim. But I'm not sure how you dim fluorescents while maintaining the striking voltage. Did they feed them with a crude square wave that remained above the striking voltage for an gradually-decreasing portion of each mains cycle, a bit like you'd dim LEDs? |
Connectors - and ring mains
In article , Dave Plowman (News)
wrote: In article , SH wrote: They are bigger. Still used in theatres. ^^^ The reason for that is if a plug had a fuse in it and it blew during a live performance, it was not a quick or safe job to get a maintenance man out to climb into the suspended walkways in the dark, find the plug, unplug it, take it apart, replace fuse, reassemble the plug, plug it back in and vacate the suspended walkways. Err, theatre lighting doesn't use a ring main. Most usually a radial with dimmer control. You don't want such circuits confused with a GP mains supply - hence different connectors. yes, but the reason is you don't want a fuse in some remote part of the rig. -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
Connectors - and ring mains
On 10 Apr 2021 at 11:32:56 BST, "Theo"
wrote: Max Demian wrote: I would have thought it would be better to have fused sockets, then there wouldn't be the chance of overload with multiple appliances plugged into the socket with an unfused adapter. The circuit breaker (or rewireable fuse) is supposed to protect the house wiring. The plugtop fuse is to protect the appliance wiring. A fused socket can't tell whether you plugged in a 1A appliance or a 13A appliance. If the 1A appliance starts taking 10A its cable may melt, but a 13A fused socket wouldn't notice. By putting a 1A fuse in the plugtop you can protect the appliance's cable. If you're running a multiway extension then that has a fuse in /its/ plugtop which is matched to the maximum current the extension can handle. If you daisy chain extensions, or plug in three kettles, that fuse should blow before troubling the circuit breaker. There shouldn't be unfused adapters, because then you're only relying on the circuit breaker. If you have a removable appliance cable, like a C13 'kettle lead', the same holds if the fuse in the plugtop is rated for the size of the cable - it's fine to fit a 10A fuse on a C13 cable capable of carrying 10A - as long as the appliance has its own fuse (typically at the IEC inlet) rated for its own requirements. Theo How has it come about that electricity plugs are called "plug tops" and electricity sockets are called "plug sockets"? There seems to be no ambiguity using just "plugs" and "sockets". -- Roger Hayter |
Connectors - and ring mains
On 10/04/2021 13:02, Roger Hayter wrote:
How has it come about that electricity plugs are called "plug tops" and electricity sockets are called "plug sockets"? There seems to be no ambiguity using just "plugs" and "sockets". I have wondered about that. Makes no sense to me, at all. |
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