Around 50-55 years ago an elderly neighbour gave me her sons (killed in WWII london bombings) dockyard electrical apprentice notebooks and text books which included a book who's title was something like 'Modern electrical wiring practice' it was dated pre-war, thats pre 1914 describing wiring ring mains using lead sheathed and open wire methods (something like 'pin and tube' method).
Fused spur - distance to draining board
- Thread starter DaveFix
- Start date
Ring mains were common board ship too, pre-wwII
I have no idea whether one of these is the book you mention, but it looks fascinating!
(If anyone has a VPN, the book is out of copyright in the US!):
https://books.google.co.uk/books/ab...EACAAJ&source=kp_book_description&redir_esc=y
https://onlineshop.oxfam.org.uk/ele...ial-electrical-machinery/product/HD_300321020
Thank you for my Christmas present!
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No it was a single volume, more like A5 size and 1/2-3/4" thick.I have no idea whether one of these is the book you mention, but it looks fascinating!
(If anyone has a VPN, the book is out of copyright in the US!):
https://onlineshop.oxfam.org.uk/ele...ial-electrical-machinery/product/HD_300321020
Thank you for my Christmas present!
Hmmm - I still have to wonder about 1897
What, I wonder, would have been the reasoning behind having a ring circuit 'pre 1914' ?
Kind Regards, John
I don't recall the publication including a reason, just the implementation.Hmmm - I still have to wonder about 1897
What, I wonder, would have been the reasoning behind having a ring circuit 'pre 1914' ?
Kind Regards, John
It probably doesn't, but that doesn't stop me wondering about a reason "pre-WWI"
I have no idea whether it is true, but the general belief seems to be that ring finals were introduced after WWII because of a (I presume war-related) copper shortage.
Kind Regards, John
Hmmm - I still have to wonder about 1897
What, I wonder, would have been the reasoning behind having a ring circuit 'pre 1914' ?
Kind Regards, John
I would have thought, voltage drop?
Having a ring circuit, per se, does not reduce voltage drop - it's all a matter of CSA (hence also 'amount of copper').
Even in the (fairly silly, and probably rarely seen) extreme case of a ring in which the cables of both legs follow identical paths, the VD at the 'farthest socket' will be the same a radial as with a ring using cable of half the CSA of the corresponding ring - and if the routes of the two legs are (as usual) not identical, then a radial would have the same VD as the ring with a CSA less than double that of the ring ...
... that's why, in practice, the VD (at farthest socket) will usually be similar (maybe even less) with a 4mm² radial as compared with a 2.5mm² ring final.
eric frequently quotes the 'maximum length' of a 2.5mm²/32A ring final as 106 metres. I think that's rather misleading, since it means that, at best, the farthest socket can only be 53 metres from the CU, and the situation with a hypothetical 5mm² radial would be exactly the same.
Kind Regards, John
I am sure everyone knows the difference in what is meant by "the UK ring circuit" - for sockets - and any other circuit that happens to be wired in a ring for specific reasons.
I wouldn't be as sure as you about that
As far as I can see, the most common 'other specific reason' one sees mentioned is VD - but, as I've just written, unless there is some (presumably 'practical') problem with using cable with a larger CSA, a ring arrangement doesn't really offer any advantage over a radial in that respect.
Kind Regards, John
Interesting reading here:
https://docshare.tips/ring-circuits-history_59561033dc0d600757986b04.html
Apparently an editorial in the 1938 'Electrical Review' called for simplification of electrical circuits - although there is no record that this was discussed in the 'Wiring Regulations Committee'
... and again, this isn't proof that the ring circuit wasn't already in use elsewhere!
https://docshare.tips/ring-circuits-history_59561033dc0d600757986b04.html
Apparently an editorial in the 1938 'Electrical Review' called for simplification of electrical circuits - although there is no record that this was discussed in the 'Wiring Regulations Committee'
... and again, this isn't proof that the ring circuit wasn't already in use elsewhere!
The ring final circuit, as in supplying 13A outlets, was first mentioned in the Wiring Regulations in the 11th edition, this example being the amendments from 1943 subsequently reprinted 1945.
Rings as a concept wasn't new, they had been used for submains previously, this example from the 10th edition 1934:
and even before that, any electrician or electrical engineer was free to design whatever circuit arrangement they considered appropriate for the particular installation.
The same applies today - if rings were deleted from BS7671, they and other variations of them could still be used. The difference being that proper circuit design and calculations would be required for each installation, including consideration of whether such an arrangement would be appropriate, rather than people blindly following the specification of one particular circuit design from over 70 years ago.
Rings as a concept wasn't new, they had been used for submains previously, this example from the 10th edition 1934:
and even before that, any electrician or electrical engineer was free to design whatever circuit arrangement they considered appropriate for the particular installation.
The same applies today - if rings were deleted from BS7671, they and other variations of them could still be used. The difference being that proper circuit design and calculations would be required for each installation, including consideration of whether such an arrangement would be appropriate, rather than people blindly following the specification of one particular circuit design from over 70 years ago.
My presents have arrived! 
...and nothing changes!
As well of lots of mention about the benefits of using concentric wiring!
...and nothing changes!
As well of lots of mention about the benefits of using concentric wiring!
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