i think your on to something with the cut wire- wont do no good to have the machine grounding itself, if it dose not tie the the house grounding system network...... however???
and ill say again, im no exspert and dont pretend to be- however that ground system is a extra safty feature, to help you not to get shocked, i dont think it should be grounding a load all the time-------
i think- somewhere besides the machine grounding not being tied to the home ground you have some sort of a grounding issue, i dont think its hot or you would be poping fuses real shocks ect, but i think current is going thought some object regulating load, then finding its way to the machine grounding system and woundering around.
i happent to live in a house fairly old, (not by italy standards of course) made it 1880, it has 2 prong system, in much of the house, and the 3 prong- i have ran a pin or 2 a time or 2- and have never received un unwarented shock!!!
p.s. dont worry about the "polititicans" and "some people"- there doing 'it" everywhere