Well, I thought the same but now I know it works for sure. About a month ago when I dip my finger I could feel a strong current on a cut I had on my finger. It felt like lemon juice on an open cut. Definitely painful. I unplugged different equipment and at first the charge seemed to dissipate, but it would come back a few hours later. Long story short I plugged the grounding probe into a power strip but the voyage was still there. A friend of mine suggested that I plug into the wall socket and that worked. No more voltage ever since.