Insulation resistance testing on eicrs

[Farmelectrics]

Advice or quicker ways for doing i r tests on an eicr generally what I have been doing over the years is live to earth neutral to earth and joining live and neutral together then testing to earth job done but my pal who has recently had his annual nice i c visit said he's been shown a new method of doing it by his inspector using a low ohm clamp meter and applying ohms law bit confused and looking for advice if true how to do this and is it achievable

 

[Dillb]

A IR test needs to be done at the relevant voltage as per BS7671, so trying to apply ohms law wont work. Be intresting to know what else the “assesor” doesnt know.

 

[Risteard]

I presume he is trying to measure the Earth leakage. There is merit in this approach but BS7671 doesn't recognise it as an alternative.

Out of curiosity the OP states that he measures phase to Earth and neutral to Earth, and then live conductors connected together to Earth. Why the first two tests and not just the live/Earth test? There could also be a risk of damage to equipment with a phase/Earth and neutral/Earth test which is mitigated by connecting the live conductors together.

 

[Farmelectrics]

If I'm honest dill totally agree but my mate was adamant even though he didn't explain it well hence my confusion stick to my old ways though must admit the ir tests can be difficult when some of the 36 way boards are chocker and access to the neutral bars and earth bars are difficult with out stripping the whole board down

 

[westward10]

I have learnt over the years that assessors like to come armed with a piece of information they think will impress you and show what geniuses they are. I prefer to convince them otherwise.

 

[cliffed]

I mentioned this to our gaffer ages ago,nothing ever came of it.
I think it’s a good idea,especially in a big complex,when doing EICR testing,where disconnecting becomes a headache.
Obviously on easier projects always the right way,is always the best way.concerninhg IR tests.

 

[Andy5678]

So can anyone explain the clamp method?

 

[Pete999]

A IR test needs to be done at the relevant voltage as per BS7671, so trying to apply ohms law wont work. Be intresting to know what else the “assesor” doesnt know.

Yes very well said Dillb

 

[Deleted member 26818]

Testing Line to Earth then testing Neutral to Earth, is fine if you then test between Line and Neutral.
Doing three tests to Earth is a waste of time, might just as well do a single test with Line and Neutral joined and test to Earth.
If you’re worried about vulnerable equipment, and can’t be asked to identify, disconnect or link out, then you would do better testing between Line and Neutral at 250V.

 

[Pete999]

So can anyone explain the clamp method?

An even bigger question for me what is a low ohm clamp meter?

 

[Deleted member 26818]

An even bigger question for me what is a low ohm clamp meter?

Bad spelling?

 

[Pete999]

Advice or quicker ways for doing i r tests on an eicr generally what I have been doing over the years is live to earth neutral to earth and joining live and neutral together then testing to earth job done but my pal who has recently had his annual nice i c visit said he's been shown a new method of doing it by his inspector using a low ohm clamp meter and applying ohms law bit confused and looking for advice if true how to do this and is it achievable

Suggest that your Mate gets a detailed method statement from this NICEIC Bloke

 

[Wilko]

IR testing L-N with any loads connected is just pointless. Otherwise they wouldn't be loads ... or have I missed something?

 

[Farmelectrics]

Think you missed something wilko live and neutral together and the test to earth

 

[Wilko]

Forum got the shakes
Yes, I agree the (L+N) to E once there are connected loads. Commenting on post #9 really.