[rickboyce]

If you want a deep dive this video made by a British electrician is worth a watch https://youtu.be/hZN6hiGLtrE

In a perfect world a ring circuit is a clever invention - it offers a circuit that can safely deliver about 7.3kW with hardly any more copper than normally could deliver about 4.6kW.

However in practice they have a hidden failure mode - if you break the ring they will carry on working apparently without problem except it’s quite possible that you now have overheating cables in a wall somewhere. In the real world houses are full of changes (both DIY and professional) that inadvertently break the ring and it’s not at all uncommon to see in a house with even modest refurb works having been done.