The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

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 31 subscribers
  • Views 7716 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
    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.                                                                                                                                                                                                                                                                                            


Reply
  • 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.                                                                                                                                                                                                                                                                                            


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