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EICR and IR Testing

Former Community Member
Former Community Member
Oh the bane of IR testing on EICRs

Now its just impracticle to disconnect all loads to carry out IR testing, I think everyone can agree on that. And that Phase and Neutral are connected then tested to earth.


This is what I do, and then test @250V as to avoid damaging any equipment in the installation. And unless the IR value was <.5 Meg, would not bother me. What BS7671 states, but BS7671 is maybe somewhat unclear in that if that voltage (250V) was used then .5meg value should used, but that value should only be used on SELV, and PELV. Now experience also tells me that even if you had a return 0.0, and then did Kohms by using the ohms setting, even values of 100Kohms are fine. (Actually can be much lower than this) and we are pretty clear that its not the cable reurning these values.


So question is when doing an EICR @ 250V, at what point would you recommend an FI? For me the value would have to be <.5Meg
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    Sparkingchip:

    I went south of the river last Thursday to do what should have been a straightforward job, until I saw the cable that supplied the central heating system that I was planning to extend.


    You do have to appreciate just how bad the insulation is on some cables that are in use without tripping a RCD or MCB in a relatively new dual RCD consumer unit.


    cc3c406e19459a9746a2bb1eee2815e0-original-20200820_144553.jpg




    Going off topic, try identifying the conductors by the colour of the remnants of the insulation around them and although I said it’s rubber cable, I not actually certain that is a precise description. The house was built as a very upmarket semi-detached in one of the best locations in Greater London and this cable may be the last bit of the original installation from 1935 that was still in use, so may be eightty give years old, the rest having been rewired around sixty years ago.                                                                                                                                                                                                                                                                                            


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  • 0
    Sparkingchip:

    I went south of the river last Thursday to do what should have been a straightforward job, until I saw the cable that supplied the central heating system that I was planning to extend.


    You do have to appreciate just how bad the insulation is on some cables that are in use without tripping a RCD or MCB in a relatively new dual RCD consumer unit.


    cc3c406e19459a9746a2bb1eee2815e0-original-20200820_144553.jpg




    Going off topic, try identifying the conductors by the colour of the remnants of the insulation around them and although I said it’s rubber cable, I not actually certain that is a precise description. The house was built as a very upmarket semi-detached in one of the best locations in Greater London and this cable may be the last bit of the original installation from 1935 that was still in use, so may be eightty give years old, the rest having been rewired around sixty years ago.                                                                                                                                                                                                                                                                                            


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