Neon mains tester question

Discussion in 'Electricians' Talk' started by yorkyguy, Jun 29, 2015.

  1. CGN

    CGN Screwfix Select

    Thinking about it, I would check the screws with your tester on the new switch. If ok, then it's probably your original switch at fault. Try reconnecting then hold back against wall with something non conductive. Do you still get a reading? If no, put screws in and tighten. Reading? If yes, then maybe the screws when tightened are causing the switch innards to deform slightly somehow causing a high resistance to earth.
     
  2. yorkyguy

    yorkyguy Active Member

    Thanks for this CGN.
    Didn't check the postings yesterday. :) I'll give it a try when I go up. Your suggestion sounds the only possibility. I have an identical switch in another location courtesy of our host. ;) - I'll swap them an see if the fault 'follows' the switch. If not then its the location/wiring/earth. I may rewire this tx and try to eliminate as many possibilities as I can.
    My bottom line is that like Mr H, I discovered it by accident - its been fitted a number of years and never caused any concern so I may leave it but observe carefully. What do you all think?
    Is a standard mulitmeter any use for exploring further?

    Cheers every one :cool: man its hot!

    B
     
    CGN likes this.
  3. MGW

    MGW Screwfix Select

    I have used a neon tester for years the VI13700G does a good job and is often supplied with the proving unit. However that is very different to a neon screwdriver which I also use in the main to alert when I have a borrowed neutral. The screwdriver neon is not really test equipment just an extra string to my bow but the Martindale VI13700G with two connections and 4 voltage rated neons is.

    This is repeated with many other items used to test. The EZ150 from Martindale does a loop test but it is not to the same standard as using a loop impedance meter.

    The Martindale ET4500 is multifunction so could be classed as a multi-meter but it is very different from the £5 multi-meter you get in the DIY store there is a reason for that £575 price tag.

    We look for ohm meters which on the low ohm range pass at least 250mA and likely have a full scale reading of just 5 ohms and a high ohm meter uses 500 volt for the test as designed to test the insulation. The £5 multimeter will not do this.

    It is hard selecting test gear the Martindale 4 neon tester will not trip the RCD measuring line to earth but some of the multi-LED types will. I had two multi-LED types one with a 12 volt battery which also tested continuity and one without they looked near identical but without battery it would trip the RCD the one with battery would not however if battery was flat it could give wrong readings.

    I am lazy at heart and when the clamp-on meter is in my tool bag and the 17th Edition test set is back in the car it is tempting to use the clamp-on meter. In fact I often do. However I am aware of its limitations and if I get odd readings then it's a trip back to the car.

    Even with extra low voltage one can get caught out. Using a 10,000 ohms per volt meter on a car is useless you actually need a lower quality and a 500 ohms per volt meter does a better job.

    You reach a point where you have to either buy expensive test equipment or admit defeat. AVO did a special auto trade meter with low ohms per volt but most meters today are very high ohms per volt. The Martindale MTL20 tester is basic with just a bulb latter versions had a solenoid as well but my early version was just a simple bulb. It could have been a simple table lamp with two leads it would have done the same job. OK proper version had GS38 leads and fused so safer to use but point is it needed some current to work. So capacitance and/or inductive coupled voltages did not show up.

    With old AVO Mk8 multi-meter I would often switch range and check the voltage on another range if the same then likely not capacitance and/or inductive coupled but it the voltage varied then likely it was. Today meters tend to be digital so swapping range does not help.
     
    PaulBlackpool likes this.
  4. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    Morning all,
    1 Can I do an earth loop/z/insulation test with my multimeter?

    :(
     
  5. yorkyguy

    yorkyguy Active Member

    I'll take this as a NO. Simply C & P and adding a smiley is of little help to anyone.
    Does a Neapolitan 6th have a doubled 3rd? Ask me and will tell you and not leave you guessing.;)
     
  6. CGN

    CGN Screwfix Select

    A man of music :)
     
  7. yorkyguy

    yorkyguy Active Member

    Cor! You are on the wrong forum mate :):):):)
     
    CGN likes this.
  8. CGN

    CGN Screwfix Select

    Best kept separate Brian ;)
     
  9. spinlondon

    spinlondon Screwfix Select

    I would suggest binning the neon screwdriver before considering any other action.
     
    sparky Si-Fi likes this.
  10. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    An Spark would not ask this on an "Electricians forum" the clue is in the title
     
  11. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    'kin Neon Screwdriver, spose its better than the back of a Thumb nail as the very old school used to do!
     

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