In message , Harry Bloomfield
writes
Onetap has brought this to us :
My Mum thought the electric leaked out of 3-pin sockets that were
left switched on with nothing plugged in. I pointed out the little
plastic shutters on the L & N pins that stopped the electric leaking out.

She grew up a long way from mains electricity.

My other half insists on turning the switch on a socket off, before
unplugging. She seems never to have come across unswitched 13amp socket
outlets.

And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs leading to
pitting and degradation. In the worst case heating such that the
Beryllium copper contacts lose their *spring*.

Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

--
Tim Lamb