"Andrew Gabriel" wrote in message
.. .
In article ws.net,
"Doctor Drivel" writes:

When was it universally adopted? I think the 1960s.

1946 supplement to the 11th Edition Wiring Regs was when it was
officially sanctioned, but people had started using ring circuits
beforehand. Installation was universal by 1950, except in towns
which didn't yet have a 200-250V AC mains supply (13A sockets

My mothers house was new in 1953, was 250V, 3 pin plugs and radials.
Radials are not outlawed and rings are not mandatory. Even today it is take
your choice. AFAICS, rings became common in the 1960s.

snip historical misinformation