Hi Lugia, and Oldan,

Why not simply use the ground of your house's electric circuits? If that one has been done properly (since about the '60s or '70s that should have been done properly), I actually don't see an issue here. It wonders me actually that it happened at all... perhaps some issue with the electricity wiring within the house/apartment? It might be worth testing the ground within the building since this seems a pretty important matter to me... unless I am missing here something?

Kind regards and good luck with the troubleshooting, Garfield.

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