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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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    John Peckham:

    Chris


    You have fallen in to the usual trap of not understanding the major difference between Initial Verification and Periodic Inspection and Testing.


    John, that's a bit unfair!


    My point was that for a periodic, L-N testing is unnecessary and as the OP said, practically impossible. How would you test a socket circuit with SRCD or USB where the manufacturer's instructions are that it should be disconnected when IR testing?


    As an aside, when testing at stages during erection, to start with the IR rapidly goes up to > 999 MΩ; but after a while it creeps up more slowly, especially when testing live to CPC. > 500 MΩ is certainly enough for me, but one could stop pressing the button as soon as it gets over 2 MΩ, or any value in between.


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    John Peckham:

    Chris


    You have fallen in to the usual trap of not understanding the major difference between Initial Verification and Periodic Inspection and Testing.


    John, that's a bit unfair!


    My point was that for a periodic, L-N testing is unnecessary and as the OP said, practically impossible. How would you test a socket circuit with SRCD or USB where the manufacturer's instructions are that it should be disconnected when IR testing?


    As an aside, when testing at stages during erection, to start with the IR rapidly goes up to > 999 MΩ; but after a while it creeps up more slowly, especially when testing live to CPC. > 500 MΩ is certainly enough for me, but one could stop pressing the button as soon as it gets over 2 MΩ, or any value in between.


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