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.


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Clive Page