IR testing . . .

doodarr · Nov 4, 2011

Hi Guy's totally new to website.

Quick question. Doing a new install and the IR for N-E is 87.6 M ohms for first half of the split board. L-E & N-L are both >500 and the complete second half of the board is >500 for all results.
Could it possibly be how close the wires are in the CU giving a lower reading. I'm not worried and know all results pass regs but its just for my own satisfaction.

Thanks

GLENNSPARK · Nov 4, 2011

Might be a bit of damp/moisture......retest when dry.........

BluSparx · Nov 5, 2011

doodarr said:
BluSparx,

The lights and bolier are not yet connected therefore I could only test the 20A Radials which were fully installed. They will be re-tested again at the weekend along with the rest of the tests for a full re-wire before energised and after lights and boiler have been connected to new CU.
I know how to test IR which is how I got the results . . my question was any idea's why the N-E IR was lower on the 1st bar than the 2nd when tested.
I also said I hadn't retested - as in disconnected everything on bar 1 and earth to check which MCB was dragging the IR down as was suggested on here.
Trying to get the results perfect and improve my knowledge thats all.
This was all explained in the previous posts.

TBF I understand what your asking but as I said unless you test individually you would not be able to complete your test cert correctly. I get sick of seeing made up results on test certs that are so obvious it beggers belief.

If you had tested individually first your circuit dragging the readings down would have given you a clearer indication of where the problem lies, if all the circuits where fine then it could be a problem with a loose connection, the bar screws etc.

Also the questions that are asked on the forum from "sparks" sometimes makes me wonder how people managed to complete there courses and qualifications.

I aint having a pop at you but IR testing and identifying the cause for low readings should be pretty straight forward

doodarr · Nov 5, 2011

It is straight forward. One ofthe easiest tests there is. I never make up results which is why I was annoyed that my results weren't >500.
just after some original ideas for any reasons why that could be before I go back. 2 heads is better than one etc.
That's what I thought the forum was for ----ing ideas about. I'm new so sorry if it isnt.

Richard · Nov 5, 2011

Have you split the circuit?

I would test individually to Identify which circuit it is pulling down your value and check terminations. I'v had it before where insulated cables crushed in the backbox have brought down readings.

Rich

Deleted member 9648 · Nov 5, 2011

BluSparx said:
TBF I understand what your asking but as I said unless you test individually you would not be able to complete your test cert correctly. I get sick of seeing made up results on test certs that are so obvious it beggers belief.

If you had tested individually first your circuit dragging the readings down would have given you a clearer indication of where the problem lies, if all the circuits where fine then it could be a problem with a loose connection, the bar screws etc.

Also the questions that are asked on the forum from "sparks" sometimes makes me wonder how people managed to complete there courses and qualifications.

I aint having a pop at you but IR testing and identifying the cause for low readings should be pretty straight forward

A tad harsh I feel...as far as I can see the OP knows how to carry out IR tests and knows what results to expect...he has not claimed to be an expert and is clearly trying to improve his testing knowledge...nothing wrong with that as far as I can see.

telectrix · Nov 5, 2011

agree there , wp, OP is part way through his testing, if i read his posts correctly and has come across a lower than expected reading. this could be ,as previously suggested, a squashed cable , or even a socket face that has been exposed to moisture prior to fitting.