British Electrical Plugs and Sockets

The video states implies that all British construction uses ring circuit or ring mains wiring. The ring mains wiring system was developed during World War II, motivated in part to conserve copper, which was scarce due to wartime uses. Running a single loop of high-amperage wires with all outlets and lamps attached uses less wire than a radial circuit in which separate wires are run from a distribution panel to each area, feeding only outlets and lights in, typically, a single room. The ring mains architecture requires every outlet to have its own fuse, since the main fuse at the end of ring has a very high amperage which is insufficient to protect individual devices plugged into outlets. This has the advantage that the fuses on individual items plugged into the outlets can be sized appropriately to that device, and blowing one only affects it and not others plugged into the same circuit.

While ring main installations remain the most common in the UK, new construction often uses radial circuits, which allow each individual circuit to be controlled by its own breaker on the distribution panel. However, even if the installation is radial, the switched outlets and fused plugs are still used.