ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades In the name of safety

GE had a solid pin on their cord caps, I think they got out of the wiring device biz though.

Many of those were probably people wanting to plug it into a non-ground outlet, and had no adapter handy...

Back in the late 70's at college, my dorm had the crowfoot configuration outlets (the Aussie style pattern) in the laundry room, and whoever installed new washing machines took pliers and crushed the ground pin and twisted the blades on the NEMA plugs to make it fit into the crowfoot outlet...

BS 1363 has the advantage of being designed in 1946 after we had the best part of Britain's cities flattened by nazi bombers, V Bombs and crude Ballistic Missiles- [ yeah, I know, Boo Hoo ] - and before the bean-counters began to run manufacturing. I was a kid then, and we used to collect schrapnel, lumps of Heinkels and bits of bomb casings as a hobby- it beats collecting stamps for street cred! We had to rebuild with minimal use of copper, which led to the Ringmain. It's existance keeps the BS1363 plug alive- because all those existing Ringmains need fused plugs which need Ringmains which....
If we redesigned today, those same VP bean-counters would inevitably come up with a material-lite product prone to the very faults that Trumpy pointed out in his OP. Anyone remember the free plastic toys out of the Kelloggs Corn Flakes boxes? A direct descendent of Shuko!

How does a fused plug need a ringmain? On this side of the pond, no ringmains, but there have been some fused plugs (had some on older Christmas tree light strings, presumably to protect the thinner wires of the string).

I've read explanations in the past of how the ringmains are wired, and I just can't picture how this saves copper. Would anyone want to explain?

I always wanted to ask pretty much the same thing - what's the difference between one 32A ring mains and 2 16A radials using the same wire (but a few metres less because the ring needs to be completed) except 1 MCB or fuse? (not counting the arbitrarily maximum area served by radials in the UK). The possible load is exactly the same and you save some wire!

I've even seen fused contour plugs! (1000W movie light).

Well...I think it worked like this... in the old days of BS546 (round pin plugs) you were only allowed one 15Amp socket per circuit. That meant for every socket you had to run a separate cable from the fuseboard, thus, wiring a whole house meant lots of cable runs unless you only had one or two sockets. After the war they wanted homes to be more modern and have more than a couple of sockets for the whole house. It was then they came up with the ring system - one big loop of cable around the house - and wonder of wonders - you could have one socket in each room!!! Which is about the maximum they ever fitted back then and indeed it seems until the 1970s. All this and if you planned the run right, you could use very little cable, or at least that was the theory. In these more modern times of many sockets and not so short supply of copper the ring system is a bit pointless. Also in my view as a contractor, it can become very dangerous too. I have often found cases of one side or more of the ring becoming "not a ring" for various reasons and then the whole load is being carried on one piece (in fact a radial) of 2.5mm cable and often protected by a 30Amp rewireable fuse of all things!!! I personally never install ring circuits any more for this and other reasons.

Uksparx, thanks much for your detailed explanation. Now I get the picture!

So basically it was all due to the arbitrarily chosen maximum number of one socket per radial?
Sounds pretty crazy from today's point of view...

Indeed it appears that was the case - I agree, totally crazy! You have to remember this is Britain and we are very good at following rules, however mad they seem!!