Testing

Discussion in 'General Electronics Chat' started by mmkawa, Nov 11, 2014.

  1. mmkawa

    Thread Starter New Member

    Nov 11, 2014
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    Today while i was checking my outlet(3 pin with live, neutral and ground), with a neon contact tester (on the live wire point/hole) and i got a shock(the tester should be plugged directly in the socket and user touches the metal part so the light glows), i don't know the reason, I tried it again it was the same, I used the same tester on other sockets and only light glows as usual but don't get shock, initially i thought its because of the ground wire which might got cut in between or something like that. But why does a live wire require a ground and where does grounding come into this, cause i am directly testing on the live wire?
    I also tested with my electric appliances and there was no shock on touching the metal part. Its not the fault of tester, tested with other neon tester same result.
     
  2. Brownout

    Well-Known Member

    Jan 10, 2012
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    It could be that your live and neutral wires are switched. Using an AC voltmeter, measure from both live and neutral to ground. You should see the usual voltage from the live to ground, but not from neutral. If you're seeing voltage between neutral and ground and not live to ground, then your outlet is cross-wired.

    I just today performed this experiment in the US.
     
  3. mmkawa

    Thread Starter New Member

    Nov 11, 2014
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    I will check that. But why I got a shock at the top of the tester? And tester was glowing, indicating the presence of current.
     
  4. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    What is the model number of the tester ... or can you post a picture?
     
  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    What country/voltage/frequency ?
     
  6. mmkawa

    Thread Starter New Member

    Nov 11, 2014
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    India 220V 50hz. And both testers have a range of 100 to 250V. I will need to test the voltage using voltmeter I guess.

    Thanks.
     
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    If you are required to make your body part of the circuit to test an unknown outlet then please please please throw this thing away as it is potentially dangerous (no pun intended).
     
  8. mmkawa

    Thread Starter New Member

    Nov 11, 2014
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    you mean throw away the tester?
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Just about every electrician in the UK (240v) had one of these screwdrivers, they had a metal pocket clip at the top, the top had to be held when testing in order to use body leakage to ground, otherwise the Neon did not light.
    I believe they are still available.
    Max.
     
  10. mmkawa

    Thread Starter New Member

    Nov 11, 2014
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    So is it normal to get a shock on the top.?
     
  11. studiot

    AAC Fanatic!

    Nov 9, 2007
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    I like this video

     
  12. ISB123

    Well-Known Member

    May 21, 2014
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    It's not normal.Screwdriver tester are banned in some countries because if internal resistor and lamp fail and short circuit you are basically poking your finger in 220 Volts.
     
  13. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Also this one.

    Is your tester a Neon or LED tester?

    I expect the resistor has failed.

     
  14. MaxHeadRoom

    Expert

    Jul 18, 2013
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    No the internal resistance was not enough for the current to be felt.
    Max.
     
  15. ian field

    Distinguished Member

    Oct 27, 2012
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    Where you also touching something earthed - such as leaning against a radiator?

    The tester I'm thinking of resembles a screwdriver, but has a hollow clear plastic handle, inside that is a high value resistor, a neon bulb and a spring to keep all the contacts pushed together.

    They are designed to light with very low current pretty much using the capacitance of the users body as a load to the AC current.

    The resistor should be high enough to limit current to a safe value in any situation.

    The only things I can think of is a 110V tester on US house wiring that also has 220V outlets - or maybe the tester got wet somehow since the previous socket.
     
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