writes:

On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket.

How can you see a spark inside the socket when you switch off the
socket

The light from an arc like that is really very bright,
easily bright enough to see through the plastic of a typical
socket.

A few years ago one of the cats in the house where I was
living "sprayed" on the wall above an electrical socket and
it ran down the wall into the pattress box. I didn't see
him do it and he had moved on before I noticed anything, but
I heard a peculiar hissing noise and when I turned round I
could see light shining from the socket -- through the face,
off to one side of the holes -- and quite bright despite
having passed through the plastic. It gave me quite a
fright! And the smell of hot electrolysed cat **** is,
shall we say, distinctive.

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2008-04-26)