Electric / earthing help please

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  • Electric / earthing help please
  • I live in Thailand with 2 pin plugs throught my (landlord’s) house.

    It has a “ground-fault circuit interrupter” set to ‘sensitivity 25’. The other settings are 5, 15 and direct.

    Our shipping arrived yesterday so was able to set up my PC and the whole case (and any metal peripheral) now gives a shock. Not a painful one unpleasant. I can cope with it except that I have two keyboards. A metal Mac one for coding and a plastic one with cherry switches for typing. The Mac one is too ‘live’ to use comfortably.

    Is there anything I can do to stop the case giving a shock? Should I be worried? I have a 19 month old who’s exploring everything.

    I did some googling and the only thing I saw that I could try is rotating the plug 180 deg. I did. It didn’t help!

    Thanks a lot,


    The earth fault thingy…

    I assume that switch mid-right sould be pointing to the red rather than the green. Honestly, I have no idea about the ‘leccy!


    Earths are important for computers. My old G4 could give you a wee belt down the earth if you unplugged it and touched the pin and they cause loads of grief attached to PA systems.

    2 pins sound like there is no earth. get a sparky to fit one. You risk damaging your pc.



    I’m no sparky but I did a course once! is that an RCD? It may monitor the power on live and Neutral and trip if they go awry, but doesn’t guarantee safety for an earth fault. They can often take a period of time to trip rather than instant disconnection where the earth comes in. You want the fault to result in off. quickly.

    Electrician required.

    GFCI (Ground Fault Circuit Interrupter) vs. Circuit Breaker


    is it likely to be a cheap and easy job? As every plug in the house is 2-pinned, I guess none of the house is earthed.


    Some computers have filtering on the input mains circuit, the filter capacitors are connected to earth. You may be feeling some of the leakage current if the house wiring is not earthed.


    Any slots in the sockets that don’t match up to a pin on the plug? Unlike the UK a lot of foreign sockets are cross compatible i.e. some can be earthed/not earthed and still work. Some countries also have earthed and unearthed plugs (like our three pin plugs where the earth pin is sometimes plastic.

    Google knows all, and with photos too 🙂


    The thing on the left looks like an RCD to me. It would point to green when it’s off – ie it’s safe to work on. The red button, if pushed, should turn off the power – I would guess it’s a mechanical test button.

    My first thought would be to see what other people do. It may be that some houses have a safety earth (ie three pins) and others not.

    The shock comes from there being a potential between the case and earth and you are making the circuit when you touch it.

    My DIY fix would be to ground the metal case somehow – a piece of wire attached to a good earth (metal water pipe/structural steel). The thicker the wire the lower the resistance and thus less voltage drop.
    In essence this is all the earth pin is on a three pin plug.

    Obviously all at your own risk – I’d check around first though.

    Premier Icon leffeboy

    a piece of wire attached to a good earth (metal water pipe/structural steel)

    I wouldn’t under any condition attach it to a water pipe. If there is something funny with the pipework such that it doesn’t go into the ground then it won’t provide an earth and then everyone will feel the buzz :). It would probably do the trick though

    You may have luck using an isolation transformer if you have one that you can try. Your two possible sources of the buzz are either the filter capacitor thing mentioned by eskay or more likely the fact that the midpoint between the two ‘live’ wires isn’t necessarily 0 so you get some leakage there. The isolation transformer would fix the second of those problems. They’re not cheap so see if you can borrow one to try first.

    Thanks all.

    The computer was shipped from the Philippines. Although the wall socket was 3 pinned (Asia style, not British), I used the same 2-pin multi-plug I’m using now and the case was never live. I guess, this suggests eksys’ guess might not be right (?)

    Premier Icon leffeboy

    If you used 2 pin in the Philippines without problems on the same computer then it is more likely to be related to the mains than your computer. An isolation transformer sounds more likely that it would work but again you would want to try one first if you can.

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