And re the IEC socket earth pin? I've read that it is best to ground it as close as possible to the IEC socket. This would mean grounding it on the rear plate. Is it best to then drill another hole in the rear plate, put a bolt and then connect it to the top plate with a wire link? I do notice that some people connect the earth (house) ground pin to the circuit ground by some kind of sequence of diodes &/or capacitors, why is this done?