Jim Gregory wrote:

Remember wiring those in the late '60s. They rattled. Lots of loose pin
parts held in check by a perforated template, and you tapped on its shell to
loosen the three (or two) pins for the gauge you needed! Then you
"unscrewed" them outward, locked them with a 3-way lever! But had no fuse!!
They was marketed for running portable equipment when you were visiting
various premises but were unsure what wall socket types to find at the
destin. So catered for 3 or 4 common formats.
BS1363 13A oblong pin sockets took off reasonably quickly in industrial and
business premises, but stretched over three decades to become universal
domestically in UK.

This reminds me of a sqwuare pin plug I had not long ago that had odd
shaped pins, not
: __
: |__|

but
: __
: (__)

I dont remember what happened to it, probably got removed when the
plugs were changed to sleeved type.


NT