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. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

As long as it isn't as bad as this one, then I think you will be OK.
http://uk.youtube.com/watch?v=iy47NzfCc20

But you should really switch the heater off on the heater first.

Toby...