I'm not disagreeing with you, I just think you are mistaken .
It would be very simple to have added a box for global IR on any cert - got shed loads of boxes for everything else.
Have you read 643.3.2 then?
I get the feeling were having a bit of misinterpreting what others are posting going on here.....
Just been scanning back over the thread...
I don't think anyone has actually said that bottom line IR acceptable value doesn't refer to the global figure...
Or that you can do a global test reading at the DB...
(if you want to)...
But one hell of a lot of the time individual circuits need to be tested as well to get the bigger picture about the condition of an installation ...
And 643.3.2 quotes detail relating to
both Global
and Individual circuit testing..
As does GN3, Examples (i) Global and (ii) Final circuit IR testing.. (Pg 51 onward)..
e.g.
eight final circuits all at 6Meg individual = Global 0.75Meg
Is a big difference than seven circuits at 200meg and one at 0.77Meg = Global 0.75Meg
OR...
eight final circuits all at 8Meg individual = Global 1.0Meg
Is a big difference than seven circuits at 200meg and one at 1.1Meg = Global 1.0Meg
In Both of the above example the second illustration has an installation where over 87% of it is in top-notch good condition only 12% is dubious..
whereas the first illustrations 100% of the installation has deteriorated down into single figure IR values...
If you just did the global value you'd miss an incredible amount of perspective on the condition of the overall installation for continual use and/or your recommended next inspection interval..
Hence why the schedule of test results have boxes for individual circuits NOT just a global value...
(which would have been easier and neater with just one box))
As a side note...
during the old annual assessment watch the monkey do his tricks performance...
I have never been asked to do a "Global IR"...
get asked for Ze's, PFCs, R1+R2's, Zs's, Ring Continuities, RCD trip times and IR's on Final Circuits...
But NEVER a global IR!
Bit like when my car comes back from MOT...
I do rather like to see individual Tyre tread depth readings..
Not just a global "All tyres are ok" comment.
Guinness