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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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    Bare conductors placed out of mind does seem to be a known installation method, but not a recommended one! (some time last century we were pulling that sort of thing out, often with black cloth tape repairs as well,  clearly some is still left operational)

    The sad thing is that a cable even in that state,  laid out like that,  probably can still passes an IR test at 1000V as well as 500V, so the instruments are useful but not all-seeing -  so looking behind a few fittings at the cable itself is really important - and that cannot find the unhelpful cases where both ends have been changed, but not the hard to reach section of cable in the middle. Still, better out than in.

    edit crossed in post, but agree totally. The IR test only gets you so far.
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  • 0
    Bare conductors placed out of mind does seem to be a known installation method, but not a recommended one! (some time last century we were pulling that sort of thing out, often with black cloth tape repairs as well,  clearly some is still left operational)

    The sad thing is that a cable even in that state,  laid out like that,  probably can still passes an IR test at 1000V as well as 500V, so the instruments are useful but not all-seeing -  so looking behind a few fittings at the cable itself is really important - and that cannot find the unhelpful cases where both ends have been changed, but not the hard to reach section of cable in the middle. Still, better out than in.

    edit crossed in post, but agree totally. The IR test only gets you so far.
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