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psu ground electricity produces voltage? Answered

I sware i was preparing for electrolysis experiment with my psu and i touched metal case of psu with my hands wet, and it was zapping me with electricity but not to high..........why?                          P.S: I used grounded cable everything is okay with ground in house, Before when i used it and touched it with dry hands it didnt zap me. I used it always before. But why isnt ground 0V.


> i touched metal case of psu with my hands wet
. Don't do that. Water, electricity, and ppl don't mix well. It's bad news when you let the magic smoke out of a component; even worse when you let the magic smoke out of yourself.

> everything is okay with ground in house
. How do you know that? Plugging some neon lights into a receptacle is not 100% accurate. It takes some specialized equipment to properly test grounding.

> touched it with dry hands it didnt zap me
. You had greater resistance when dry. See above.

> why isnt ground 0V
. Ground. Pay special attention to the third paragraph ("For measurement purposes,...").
.  The PSU probably wasn't grounded properly. See steveastrouk's and seandouge's comments.

.  And then there is always the possibility that the PSU case was at Earth potential and you were charged up.

PS: As per the fourth paragraph of the Ground link, the term ground does not always refer to Earth ground (especially when dealing with DC circuits).

okay, can someone make instructable "Homemade Ground Tester", so it checks if ground is properly attached in house because it is important when you are using wrist strap not to damage new motherboard or any other sensitive electronic components, one method is to check voltage potential difference between ground and null.

"Ground" IS zero V (or very close to). The thing on the PSU that says "ground" isn't "ground" until it's grounded.

The potential of ground depends a lot on how its wired, and if it is carrying any current. If its a long run to the real "earth" electrode, and/or the resistance of that earth is higher than expected, a very low current flowing in it, from "stray capacitance" or insulation leaks will induce a fairly high voltage in the ground wire.