I was changing a socket outlet yesterday. I switched off the mains power at the consumer unit (the big red switch) so thought all was safe. I disconnected the old socket, but when I went to fit the new one, I got a quite powerful electric shock from the wires coming out the wall. I didn't flip the other contact breakers in the consumer unit as I assumed (wrongly) that everything would be isolated.
The house is in the UK, built 1992, and has a consumer unit with built in RCD and 4 contact breakers (lights up/down, sockets, cooker).
Any ideas how this could have possibly happened? Any help would be appreciated.