Hobbyist wrote:
When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Adam.

A flash from a switch is normal, especially if it
is switching a load. If yours had a sustained arc,
that would be something to worry about. I have
increased the life of switches and other contacts
by using diodes, resistors, capacitors or MOV's to
suppress the arc. I have an adorable little electric
kettle that draws 800 watts at 120 volts AC. Of course
we colonial Hillbillies drink ice tea. *snicker*

http://www.industrologic.com/mechrela.htm

TDD