havev recently had a new central heating boiler fitted and the old emmersion heater taken out of my bathroom. The plumbers left the old water heater socket intact and is still live the light comes on when the switch is operated. I would like to use the connection at a later date to maybe add some low level lighting or something else. I want to hide the connection behind a plaster board wall and add an extended cable into my loft make it safe to be used at a later date in simple terms how do i do this