Power supply causes "Tingling" sensation

Discussion in 'IBM' started by Xerxes409, Jul 13, 2003.

  1. Xerxes409

    Xerxes409 Guest

    Recently I built a new PC with a nice 430 watt TruePower power supply.
    While putting the PC together I was horrified to feel a small
    "tingling" sensation whenever I touched any metal part on the PC case
    -- INCLUDING the metal back of my iPod when it was plugged in through
    FireWire.

    I plugged my old power supply into the same power strip and felt a
    little tingle, but not as much as the new one (it's only 300 watts or
    so).

    Anyway, it's pretty obvious that this should not be happening, and I
    need some advice. The kicker is that I live in Japan in a house that
    was built during the 1980s and there are only two-prong outlets (as is
    the case all across Japan, actually). The three-prong plug is plugged
    into a power strip that has three-prong outlets (BUT only connects to
    two-prong).

    So my question is: is a grounding problem, a wiring problem inherent
    of the house itself, or a power supply problem? (Probably not the
    latter, as the same thing happens with another power supply.)

    This is freaking me out so much I refuse to turn on the computer or
    even plug it in. :/

    -dropframetango
     
    Xerxes409, Jul 13, 2003
    #1
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  2. Xerxes409

    Arno Wagner Guest

    It is quite simple: The PSUs have input filters that put capacitors
    between the two power lines and also towards ground. In effect that
    gives you have the input voltage on the ground line as long as the
    ground line is not connected. You only get a slight tingle, because
    these filters are designed to be non-lethal when ground is not
    connected. The capacitors act as "AC-resistors" and let only a
    small current through.
    It is the grounding. The only way to get rid of this problem is
    proper grounding. You can usually get propper grounding from
    a water-line. In fact that is how it is obtained in some
    houses in Germany: Three phases run to the house and the
    zero/ground is connected to the water line within the house.

    If you have such a water line you can do an external grounding
    to make things safer: Run a wire from the chassis to a water-faucet.
    The only propper solution however is to get rid of this dangerous
    installation and do a propper 3-wire installation with good grounding
    in your house.
    Understandable.

    Regards,
    Arno
     
    Arno Wagner, Jul 13, 2003
    #2
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  3. Xerxes409

    ME Guest

    I agree, I live in a farmhouse in the uk and around 20 or so years ago the
    lead and copper water pipes were torn out and new "healthier" plastic ones
    put in, I still remember mums scream as she got a shock from the cold tap
    (just a small shock but as we work with 240 volts in the uk it could have
    been lethal), no one had thought about the houses earth was atached to the
    water pipe system, to fix it a 6 foot copper spike was driven into a wet
    area in the garden and the earth atached to it (turned out the washine
    machine was faulty and leaking power through its earth)

    Drew
     
    ME, Jul 14, 2003
    #3
  4. Xerxes409

    Wayne Guest

    I have used copper pipes for ground but I suppose there is some risk from a
    replaced pipe as mentioned ...

    The metal stake into the ground does work but the ground must be moist. One
    time when I used to live in the mountains I developed problems with a
    washing maching which would not run. When the motor would try to start the
    lights in the cabin would get _brighter_! When I told my landlord (a
    jack-of-all-trades mountain man) he went outside and started watering the
    ground next to the cabin! I thought he was crazy ... until I realized the
    problem was fixed. Turns out there was a ground stake there ...

    Wayne
     
    Wayne, Jul 14, 2003
    #4
  5. Xerxes409

    Louis Bybee Guest


    The problem wasn't fixed by the watering. The symptoms were masked.

    The neutral, or one of it's connections, between the source and the panel in
    the cabin, was most likely bad. This resulted in current flow in the ground
    (bonded to the neutral in the panel), and most likely a semi floating
    neutral. Bad - bad - bad!

    The issue should have been fixed correctly.

    Louis
     
    Louis Bybee, Jul 14, 2003
    #5
  6. Good advise, since in many parts of the US the water service to your
    home is provided by non-conductive PVC or HDPE plastic lines. Worse
    still, if you do ground to your water pipes, the electrolysis created
    can eat through part of the plumbing in your home and a flooded
    basement sometimes results (as it did for me).

    In my case, we had received "tingles" from touching the cover plates
    of outlets and switches. I had determined that the ground plates were
    at an elevated potential from ground, but it wasn't untill my daughter
    heard the "hiss" of leakign water in the basement that we realized
    why. It turned out that the final 6' of 3/4" copper pipe leading to
    the water meter has been eroded by electrolysis until it was
    paper-thin and starting to develop pinhole leaks. After installing
    roughly 80' of new 3/4" copper pipe in the house, and adding a 25'
    driven ground the problem vanished.

    Never trust the judgement of the contractor that built your house, or
    the electrician that wired it. Neither is an EE, and while some of the
    craftsmen are more informed than others, not all are aware of the
    problems (safety and others) that blind, rote practices like this can
    cause.

    Still to this day I simply cannot imagine how stupid an electrician is
    that can use a water system connected by non-conductive plastic pipe
    as a ground system, still it happened in the home I purchased.

    Harry C.
     
    Harry Conover, Jul 14, 2003
    #6
  7. Xerxes409

    Louis Bybee Guest

    I can't comment on the intelligence level of the electrician who wired your
    home, but the situation you describe is dictated by the NEC. To paraphrase
    the NEC; all piping systems in the dwelling shall be bonded to the main
    electrical panel. The water service, if it is metallic would qualify. The
    water service, again if it is metallic, and at least ten feet of the pipe is
    in contact with the exterior soil, qualifies as one of the required
    grounding electrodes. There are additional specifics as to exactly where,
    and how, the connection will take place (one reason is to avoid the example
    of a plastic section being used for repair setting up a deadly shock
    opportunity). The electrician was following a mandate.

    While the surface of a ground rod will qualify as the second electrode, the
    best option I believe to be a Ufer Ground (a copper conductor in the footing
    of your structure) as long as possible. This works in new construction, or a
    buried copper wire ring surrounding the dwelling, and brought up to the
    service panel.

    Louis--
    *********************************************
    Remove the fish in address to respond
     
    Louis Bybee, Jul 15, 2003
    #7
  8. Xerxes409

    Louis Bybee Guest


    The NEC does address the water service, and requires it to be bonded to the
    service panel.


    The NEC allows an 8' ground rod to be used as the required supplemental
    grounding electrode. In some soils, and moisture levels, the effectiveness
    is less than stellar, but it does qualify.

    The purpose of radials used by radio stations are related more to acting as
    an RF Counterpoise. They can however be a superior grounding electrode, as
    they are required to be bonded to the service panel.

    Louis
     
    Louis Bybee, Jul 15, 2003
    #8
  9. Most PSUs have 5nF RF filter capacitors between the AC lines and the
    chassis ground that can cause a tingle, but I think Antec is one of
    the few exceptions and has RF filter capacitors only across the AC
    lines. The circuit board of my Antec SmartPower is designed with room
    for those 5nF capacitors, but it doesn't have any installed.
    Shouldn't the lack of line-ground capacitor prevent tingling, assuming
    that nothing else is wrong?
     
    larrymoencurly, Jul 15, 2003
    #9
  10. Xerxes409

    ehsjr Guest

    His rationale was that a section of water pipe
    might be replaced with PVC at some point in time.

    If you use a self-grounding receptacle for the new 3-prong
    receptacle, no grounding jumper is required. If you do use
    a grounding jumper - that's what I do, whether or not it's
    a self grounding receptacle - you should use the right
    size: #14 for 15 amp circuits, and #12 for 20 amp circuits.
     
    ehsjr, Jul 15, 2003
    #10
  11. Xerxes409

    Z Guest

    What the NEC is doing here is not addressing the water service it is
    addressing the plumbing installation. The purpose of the equipotential
    bonding is to hold all extraneous conductive parts of the plumbing
    installation to ground potential.
    The water providers make their own arrangements and have their own codes
    of practice.
    Yep they are for ground planes, nominally multiples of 1/4 wavelength.
     
    Z, Jul 15, 2003
    #11
  12. Xerxes409

    Xerxes409 Guest

    The tingling sensation indicates you are receiving a small shock from

    Thanks for everyone's help and suggestions! I wound up borrowing
    around 5M worth of insulated copper cable from a mate, wrapped it
    around the house's "grounding port"/screw thingy, and then wrapped the
    other end to the grounding wire coming out of the surge protector. My
    computer is now zap-free. (Now if I could only solve the problem of
    the CMOS corrupting every time the system restarts... but that's
    another thread.)

    Thanks again!
     
    Xerxes409, Jul 16, 2003
    #12
  13. Xerxes409

    Arno Wagner Guest

    As I said, I don't know about Japan. My reference is several
    older houses in Germany. So it is definitely something to check
    locally.

    [...]
    It does. Again it does not work well when you really need
    low-resistance grounding, as for example when your utility delivers 3
    phases but no zero (as in the cases of the houses I mentioned). Here I
    would strongly recomend having a qualified professional install and
    check the grounding. But to get rid of the voltage on his chassis, the
    original poster does not need "real" grounding, since it is
    high-impedance.

    Arno
     
    Arno Wagner, Jul 16, 2003
    #13
  14. Xerxes409

    Arno Wagner Guest

    Funny _and_ impressive story. A true enginer... ;-)

    Arno
     
    Arno Wagner, Jul 16, 2003
    #14
  15. Xerxes409

    Arno Wagner Guest

    Yes, it will. No tingeling in this case.

    Arno
     
    Arno Wagner, Jul 16, 2003
    #15
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