LOW Insulation Test

nrg · Mar 28, 2011

Hi

Just done a board in a very old converted flat. Everything tested out fine except the IR on the ring. L N came back at 0.46, however when the board was put in it didn't trip the MCB or the RCD. The flat is owned by an artist and it is extremely cluttered and I am having great problems getting to everything to trace the issue. I suspect it is something plugged in that we can't find for the mess). Any advice as the customer is reluctant for us to investigate any further when everything is working ok. All other test came back fine.

Thanks

Adam

malcolmsanford · Mar 28, 2011

Carry out the the test as per reg 612.3.2 at 250v DC L-N together to earth and record just your LIVE to EARTH part on the Schedule of Results.

telectrix · Mar 28, 2011

beat me again , malc.

IQ Electrical · Mar 28, 2011

nrg said:
Hi

Just done a board in a very old converted flat. Everything tested out fine except the IR on the ring. L N came back at 0.46, however when the board was put in it didn't trip the MCB or the RCD. The flat is owned by an artist and it is extremely cluttered and I am having great problems getting to everything to trace the issue. I suspect it is something plugged in that we can't find for the mess). Any advice as the customer is reluctant for us to investigate any further when everything is working ok. All other test came back fine.

Thanks

Adam

Just as an aside to the good advice above, do you know what 0.46 MOhms actually equates to?

I only ask as you seem to think the MCB/RCD should have tripped.

It's 460,000 Ohms

A current of 0.0005 Amps would flow from this.

Guest 004 · Mar 28, 2011

and why not record neutral to earth?

Guest 004 · Mar 28, 2011

IQ Electrical said:
Just as an aside to the good advice above, do you know what 0.46 MOhms actually equates to?

I only ask as you seem to think the MCB/RCD should have tripped.

It's 460,000 Ohms

A current of 0.0005 Amps would flow from this.

that would be 0.5 milli amps then

malcolmsanford · Mar 28, 2011

MrEnigma said:
and why not record neutral to earth?

It depends on your schedule of results that you use. I used the one from appendix 6 in the BS 7671-2008, as all Schedule of results should be modelled on this. That contains 2 boxes LIVE/LIVE as the neutral is a live, LIVE/EARTH.

I know some forms ie the NICEIC have that NEUTRAL/EARTH box, but I find not everyone uses those, but everyone should use the BS 7671-2008.

Guest 004 · Mar 28, 2011

malcolmsanford said:
It depends on your schedule of results that you use. I used the one from appendix 6 in the BS 7671-2008, as all Schedule of results should be modelled on this. That contains 2 boxes LIVE/LIVE as the neutral is a live, LIVE/EARTH.

I know some forms ie the NICEIC have that NEUTRAL/EARTH box, but I find not everyone uses those, but everyone should use the BS 7671-2008.

Thanks buddy, I only use NICEIC