This means, if there was a fault with your toaster where either the live
or
the neutral was in contact with the metal casing, but the earth wire was
not
connected, if you touch the metal casing, some current will be conducted
through you to earth - the RCD will spot this missing current, and trip,
hopefully saving your life :-)

Sparks...

Just curious. How safe is an RCD. If I stood bare footed on a damp concrete
floor and grabbed the Live wire, would it still be a nasty shock but not
kill me, or does it switch off so quick that I would not even notice it.

Simon