The plumbers who did the installation when my house was converted just over a year ago were complete morons, the latest c*ck-up I've found yesterday was that they hadn't tightened the connections to a pump, finally leaving me with a slow leak that itself was fixed with a quarter turn of a spanner.
What worries me a bit is that the pump (Grundfos UP15-14B) got soaked by the leak as it was installed with the body down instead of up (not sure if that's wrong or a non-issue?). Stupidly in the dark I touched the pump first, and got a very sharp and painful "tingle" (not the full electric force though, I know the difference ;-) and whenever a drop of water hit the electric connections it vaporised. When I disconnected the pump and opened the cover I saw it was well and truly burnt.
However neither the fuse in the connection box (13amps!!!) that only serves the pump nor the fuse that also serves the central heating and boiler had tripped.
The pump appeared to be properly grounded, and all the pipes in my house are copper. I understand that not enough current was leaking to blow the fuses, but shouldn't a grounded water pump on copper pipes *not* shock their owner? I'd like to understand that all is OK for another pump to simply be fitted :-) ...