2 months ago I moved into a house from 1959 (1 220V phase and 1 neutral coming in). I noticed on the 2nd floor bathroom that there was stray voltage on the faucet (-+ 30V). No socket outlets in the house have a ground pin. When I connect a power bar (which has internal grounding), I notice a stray voltage on its sockets too.
I installed an earthing rod (260cm / 8,5feet in the ground). I tested it while connecting a light bulb (40W) between a hot wire and the ground, and it bright up. Next I connected the earth cable to the breaker panels earth bar. There were already 2 ground cables from somewhere in the house connected to this bar, and I did not remove them.
I figured this would solve the problem of my faucet, but it didn't. Whenever I would stand on the bathroom floor and touch the faucet I could feel the stray voltage.
I then connected a new ground cable from the breaker panel's earth bar to the faucet. Using a volt meter I got these 3 readouts:
1) I'm standing on the bathroom floor, and hold a Volt Meter's pin1 in my left hand, while I hold pin2 against the faucet
2) Same situation, only this time I connected the new ground cable to the faucet
3) This time I hold pin2 directly against the ground cable.
I have no idea what's going on. How can my ground cable have a voltage of 30V, when I'm measuring between the bathroom floor and the ground cable (20m / 65feet) to the earth rod?
Update 7 months later: This bathroom has been fully renovated now. I have a suspicion about what was going on initially. Under my feet, inside the flooring there was a metal tube which held insulated electricity wires. At the endpoint of that metal tube was a light switch 1 floor underneath the bathroom, and I think it probably was a faulty device leaking current (a bad light switch can act as a sort of capacitor I think). (= fault 1) The metal tube must have been connected in some way to the light switch. (= fault 2) By standing directly above this metal tube I put myself at 30V potential, and while touching the bath faucet (which I believe is a natural ground in any house) I felt this.