Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 33 replies
  • Subscribers 30 subscribers
  • Views 6759 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

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
Parents
  • 0
    If it is really that old it could be a vestige of a DC installation depending where exactly you were. An L-N E arrangement would not have been that common, hence all 3 cores insulated and the identical X-section. Conversion of said DC systems to what we now call TNS led to the fused neutral problem, that we have been fighting ever since.  Much earlier and it would have been more likely to be rubber covered singles served in cotton or double cotton (again, thinking of stuff I have pulled out ).

    Or it could just have been a handy bit of cable re-purposed at a time when it did not look quite so shabby.

    Pity really that rubber perishes, the tin plated copper looks to be in near perfect nick.
Reply
  • 0
    If it is really that old it could be a vestige of a DC installation depending where exactly you were. An L-N E arrangement would not have been that common, hence all 3 cores insulated and the identical X-section. Conversion of said DC systems to what we now call TNS led to the fused neutral problem, that we have been fighting ever since.  Much earlier and it would have been more likely to be rubber covered singles served in cotton or double cotton (again, thinking of stuff I have pulled out ).

    Or it could just have been a handy bit of cable re-purposed at a time when it did not look quite so shabby.

    Pity really that rubber perishes, the tin plated copper looks to be in near perfect nick.
Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines