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Neutral Earth Loop Impedance Testing.

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Evenin' All,

                    I am watching a film so my brain is turned off. I have just bought a lovely old 70s Clare V144 loop tester. It can test L-E loops, N-E loops, L-N impedance and earth bonding or C.P.C. resistance at high currents.


What was the perceived wisdom in carrying out a N-E loop test of old please?


Z.

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    GeoffBlackwell:

    I would not use that instrument on a site - it is similar to the Evershed & Vignoles ones that I had (before I took them apart for the bits inside ?).and they would now be considered to be too dangerous to use.


    Mine would inject around 25A for about 30 seconds to do a Live - Earth loop test.  This would blow faulty connections apart and raise the potential on the metal parts of the installation to around 240 volts.  So potentially lethal to any occupants in the building. 


    Regards


    Geoff Blackwell


     




    Hello Geoff,

                          the L-E test seems to be at 14 Amps for a maximum of 3 seconds according to the technical info. sheet. That should be enough to detect rusty old conduit couplers.?


    I have tried it at home and it is fun to use once I had burnt off the switch contacts corrosion. . Even my old (but newer than the Clare unit) Robin tester injected about 20 Amps for a split second for L-E loop tests I believe. You could see the lights dim sometimes.


    It will have its uses. It will certainly test the integrity of wiring and connections that demure small battery operated D.M.M.s can not do robustly.


    It will be used with care and consideration for my and others' safety.

    https://www.flickr.com/photos/ikbrunels/7232463806



    Z.

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  • 0

    GeoffBlackwell:

    I would not use that instrument on a site - it is similar to the Evershed & Vignoles ones that I had (before I took them apart for the bits inside ?).and they would now be considered to be too dangerous to use.


    Mine would inject around 25A for about 30 seconds to do a Live - Earth loop test.  This would blow faulty connections apart and raise the potential on the metal parts of the installation to around 240 volts.  So potentially lethal to any occupants in the building. 


    Regards


    Geoff Blackwell


     




    Hello Geoff,

                          the L-E test seems to be at 14 Amps for a maximum of 3 seconds according to the technical info. sheet. That should be enough to detect rusty old conduit couplers.?


    I have tried it at home and it is fun to use once I had burnt off the switch contacts corrosion. . Even my old (but newer than the Clare unit) Robin tester injected about 20 Amps for a split second for L-E loop tests I believe. You could see the lights dim sometimes.


    It will have its uses. It will certainly test the integrity of wiring and connections that demure small battery operated D.M.M.s can not do robustly.


    It will be used with care and consideration for my and others' safety.

    https://www.flickr.com/photos/ikbrunels/7232463806



    Z.

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