The early ring circuit, pre-decimalisation was usually wired in 7/0.29
Why are ring finals split up/down not side/side?
- Thread starter ericmark
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The early ring circuit, pre-decimalisation was usually wired in 7/0.29
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Yes, that is a factor. However, what I was getting at was that (if it were typical), the house in which I spent most of the first couple of decades of my life had just a very small number of (15A) sockets, each on its own dedicated circuit (at least, until 'DSIY' created some branches/spurs
) protected by a 15A (re-wireable) fuse, and the introduction of fused plugs enabled multiple sockets to be supplied by a single circuit, without the flex connected to the plug having to be big enough to be adequately protected by a 30A fuse.Kind Regards, John
Whatever it was wired in 15A fuse required at least 20.7A cable - and 30A, 41.4A cable.
Yes, and making it a ring allowed the existing circuit to be uprated to 30A
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Indeed - but I think we are talking about two different things (and two different ways of 'saving copper') ...
... you are talking about the over-current protection of the 'fixed wiring' supplying sockets, but I am talking about the protection of flexible cables connected to the plug. Even if (by whatever means) one arrived at a situation i which the fixed wiring was adequately protected by a 30A fuse, the flexible cables would (with unfused plugs) also have to be be large enough to be adequately protected by that 30A fuse. This presumably was a disincentive to have circuits rated >15A (and supplying multiple 15A sockets), hence the tendency for one socket per circuit. When fused plugs appeared, this problem went away, so multiple sockets per circuit (hence much less cable/copper) became possible/practical.
Kind Regards, John
I am, but the extension and doubling capacity of the 15A radial (rather than replacement) using the existing circuit was, I think, the reason for the ring circuit and it saved copper.
Fair enough. Having done the above then, obviously, the fused plug was required to prevent 'huge' flexes - and had to be different than the 15A unfused plug.
Chicken and egg, I suppose, depending on where you started. (It was the egg).
I'm a bit confused. Are you suggesting that 30A rings were created by joining together two existing 15A radials? I thought that the 'copper saving'concept of ring finals was introduced primarily (probably almost exclusively) in relation to the massive programme of new builds immediately after the war (in which case all wiring would require 'new copper')?
In as much as it uses very little new cable, joining two existing radials (in an existing property) to make a ring would obviously require a lot less 'new copper' than would putting in new circuit(s), but I'm not sure that I understand why that, alone, would have been done.
Fused plugs (to avoid 'huge flexes') were required because the circuit had been 'uprated' to a 30A one - but that would have been true whether it were a 30A radial or a 30A ring.
Kind Regards, John
I must admit, I never came across anywhere where that had been done, but I was rarely involved in any domestic stuff.
I might be wrong but, no. Houses had one socket in each room and few electrical appliances on a 15A circuit.
To double this capacity, and add extra sockets, by merely extending the end of that circuit back to the fuse-box would require less copper - and no uprating of the existing cable.
I don't really see why that would require the 'invention' of the ring final at all. Two 15A radials would do. They might have decided then to join the two, but why?
As said to Eric, the two radials would do.
No, there is no point and that is not what I was saying.
Yes I know, but 30A BS3036 radials required the imperial equivalent of 6mm² - a ring, the imperial equivalent of 2.5mm².
It seems that we are probably all agreed that it would not really have made much sense to do that.
Kind Regards, John
Indeed. That was certainly what we had in my youth. Mind you, as time passed, increasing numbers of things were pluged into that one 15A socket by means of 'Christmas trees' of assorted 'adapters'!
I'm not sure that I understand that. One could 'double the capacity' by simply adding a second 15A radial (without creating a ring), with essentially the same cable/copper implications as with what you suggest, couldn't one?
That's what I've been saying.
I've never disputed that but, as I keep saying, it was really the appearance of fused plugs which facilitated the creation of any sort of 30A sockets circuit (without invoking the 'huge' flex issue).
Kind Regards, John
I really struggle, no REALLY STRUGGLE, to follow the reasoning here.
First I'll digress and trip along memory lane:
Yes I agree that I too remember loads of radials on 15A sockets, I also remember bedrooms having just a 5A socket each on the lighting circuit and I'll go even further and say I remember the house I moved out of in 1961 having 2 CI fuse boxes with 2 fuses each, thats a 5A box feeding 2 lighting circuits, the upstairs circuit included 2x5A 2pin sockets and a 15A box feeding the 2x15A sockets (Lounge & dining area of kitchen) I clearly recall helping Dad add extra sockets to the radials and to the lighting circuits. Added to that I recall helping Dad do the same for many of the neighbours.
I was 6 when we moved in 1961 to a 3 bed semi and a similar arrangement existed for the lighting, 5A CI fuse box supplying 2 lighting circuits which included a 5A socket in kitchen and lounge on downstairs circuit. Power was a 30A CI box feeding a 6 way fusebox for 5x15A radials (3 beds, lounge & dining room). a 6th radial was quickly added for the kitchen with 3x13A single sockets (unswitched).
As we decorated each room the sockets were changed to 13A and additional sockets added to the places where power was likely to be needed and when one of the original bedroom cables developed a short to earth (somewhere within the split tube) the decision was made to link the sockets into the 2 other bedrooms to form a ring (fed for a number of years by a 15A rewireable fuse on each end of the ring). The CI boxes and wooden fusebox were replaced around mid 70's when we added an electric shower.
Just like the previous street I recall helping Dad do electrical work for the neighbours.
The house was not fully rewired until mid 90's which resulted in 3 rings: 1] upstairs (including immersion heater), 2] lounge and 3] for kitchen, dining & hall.
My understanding has always been that the ring and 13A sockets went hand in hand but I'm more than happy if this is not the case. I didn't do any new build work until mid 70's but prior to that I am unable to guess how many radials I converted to rings.
So back to topic.
Does it matter a jot which came first (Ring vs radials converted to ring)? I'll bet a pound to a penny that by the late 70's the ratio was about 50:50
First I'll digress and trip along memory lane:
Yes I agree that I too remember loads of radials on 15A sockets, I also remember bedrooms having just a 5A socket each on the lighting circuit and I'll go even further and say I remember the house I moved out of in 1961 having 2 CI fuse boxes with 2 fuses each, thats a 5A box feeding 2 lighting circuits, the upstairs circuit included 2x5A 2pin sockets and a 15A box feeding the 2x15A sockets (Lounge & dining area of kitchen) I clearly recall helping Dad add extra sockets to the radials and to the lighting circuits. Added to that I recall helping Dad do the same for many of the neighbours.
I was 6 when we moved in 1961 to a 3 bed semi and a similar arrangement existed for the lighting, 5A CI fuse box supplying 2 lighting circuits which included a 5A socket in kitchen and lounge on downstairs circuit. Power was a 30A CI box feeding a 6 way fusebox for 5x15A radials (3 beds, lounge & dining room). a 6th radial was quickly added for the kitchen with 3x13A single sockets (unswitched).
As we decorated each room the sockets were changed to 13A and additional sockets added to the places where power was likely to be needed and when one of the original bedroom cables developed a short to earth (somewhere within the split tube) the decision was made to link the sockets into the 2 other bedrooms to form a ring (fed for a number of years by a 15A rewireable fuse on each end of the ring). The CI boxes and wooden fusebox were replaced around mid 70's when we added an electric shower.
Just like the previous street I recall helping Dad do electrical work for the neighbours.
The house was not fully rewired until mid 90's which resulted in 3 rings: 1] upstairs (including immersion heater), 2] lounge and 3] for kitchen, dining & hall.
My understanding has always been that the ring and 13A sockets went hand in hand but I'm more than happy if this is not the case. I didn't do any new build work until mid 70's but prior to that I am unable to guess how many radials I converted to rings.
So back to topic.
Does it matter a jot which came first (Ring vs radials converted to ring)? I'll bet a pound to a penny that by the late 70's the ratio was about 50:50
I don't follow the logic; surely it was the proposal/prospect, for whatever reason, of the creation of 30A ring final socket circuits that necessitated the need for fused plugs.
Why, then, did only Britain think it necessary to have 30A socket circuits in domestic properties, the vast majority of which were very small?
Fair enough - but, in turn, I'm somewhat struggling to understand why you're struggling
Your memory lane is almost identical to mine (and my memories go back to the mid-50s).
[
As has been discussed, that is almost inevitably the case. Introducing 13A fused sockets for 15A radial circuits would have been essentially pointless, whilst introducing 30A circuits (ring or radial) without also introducing fused plugs would have been 'impractical'/'inconvenient' (would have required 'huge' flexible cables). Hence, as you say, it seems inevitable that they were introduced more-or-less simultaneously, the fused plugs having to be introduced because of the appearance of 30A circuits (primarily the new 'rings').
Fair enough - the reason for that presumably being the need/desire for more sockets? However, as above, when you undertook a conversion, you presumably changed all the sockets to 'BS1363' ones (if that's what there were in those days)?
It only matters a jot in terms of the discussion we were having, about the reason for the introduction of the concept of ring finals (a concept more-or-less unlike to the UK and countries historically linked to Britain). My understanding was that it was introduced in the immediate post-war period, when copper was in short supply and a massive programme of new builds (because of the war) was happening - so my understanding was that the primary intent was to reduce the amount of copper used in wiring those rebuilds 'from scratch' (which just about makes sense) rather than in relation to converting radials to rings in existing/surviving properties - not much of which probably happened in the 40s and 50s (and which, in any event, would have little, if any, 'copper saving' relevance).
What parts of that do you struggle to understand?
Kind Regards, John
As I've said, it was "the proposal/prospect, for whatever reason, of the creation of 30A
). The same 'need' would have arisen if the proposal/prospect had been to introduce 30A radial (with whatever cable was appropriate). I presume that, as you have been saying, because of the fusing factor issue (hence probably needing the imperial equivalent of 6mm cable), someone came up with the idea of a ring final to (probably) reduce the amount of copper required (at least for new-builds or total re-wires).Who knows. However, per the above, the thinking may well have been that (at least for new builds) having two (or more) sockets on a 30A ring would use less copper than having two (or more) sockets each fed by a 15A circuit. Of course, most countries did not have a post-war rebuilding project on anything like the scale of Britain (hence far less 'copper saving' issues) - although one might have expected that Germany might have felt the need to do something similar.
Kind Regards, John
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