Insulation Resistance - no reading...

[Dom]

Hi,
I've just completed a minor works for a customer and while testing the ring, I encountered an issue when conducting the Insultation Resistance test. Phase-CPC and Neutral-CPC both gave readings >500 MOhms as expected, however, Phase-Neutral is giving Zero. The tester (Fluke 1653) ramps to 2V then aborts the test with a zero reading.

Everything is unplugged, although having read some other posts, perhaps there are some neons connected which I haven't taken into consideration. Does anyone know if neons would typically result in a zero reading for IR test between Phase-Neutral?

Any help/suggestions greatly appreciated...

 

[ian.settle1]

Hi,
I've just completed a minor works for a customer and while testing the ring, I encountered an issue when conducting the Insultation Resistance test. Phase-CPC and Neutral-CPC both gave readings >500 MOhms as expected, however, Phase-Neutral is giving Zero. The tester (Fluke 1653) ramps to 2V then aborts the test with a zero reading.

Everything is unplugged, although having read some other posts, perhaps there are some neons connected which I haven't taken into consideration. Does anyone know if neons would typically result in a zero reading for IR test between Phase-Neutral?

Any help/suggestions greatly appreciated...

The isn't a FCU hidden away somewere which you may have missed?

 

[Spudnik]

Def something left switched on or plugged in hidden somewhere.

Boiler or TV booster are the favourites.

 

[scotsparky]

Immertion heatrer in loft??

Anyway on a PIR its Acceptable to combine Phase and neutral and test to earth (method 2 GN3) saves a lot of mucking about.

 

[steamboatwilly]

Did a MW in a property last year and got exactly the same. Phoned NICEIC helpline and their advice was to LIM the test and check L/N>C only. They were happy for that on a MW.

When the customer returned a few days later he told me it was a socket in a wall cupboard behind a load of junk. How would I have found that then!

 

[jamie-spark]

Hi,
I've just completed a minor works for a customer and while testing the ring, I encountered an issue when conducting the Insultation Resistance test. Phase-CPC and Neutral-CPC both gave readings >500 MOhms as expected, however, Phase-Neutral is giving Zero. The tester (Fluke 1653) ramps to 2V then aborts the test with a zero reading.

Everything is unplugged, although having read some other posts, perhaps there are some neons connected which I haven't taken into consideration. Does anyone know if neons would typically result in a zero reading for IR test between Phase-Neutral?

Any help/suggestions greatly appreciated...

Yeh you would get that kind of reading i Use a metrel eurostat and insulation readings i get through neon are 00.1

 

[DurhamSparky]

i very rare check L-N on lights / sockets when doing MW elecsa happy with L-E N-E with Lim for L-N

too many hidded things to watch out for

new builds and CU changes different matter! however i had to limit L-N on my assessment CU change as customer had built in fridge and socket was located right behind!! no way i was doing test on his fridge plugged in!!

 

[Dom]

Thanks everyone for your replies, particularly Jason.S who I think has identified the culprit - a TV booster in the bathroom cupboard (!?) Haven't re-tested yet but I'm feeling confident of a good result!

 

[cornburn]

i very rare check L-N on lights / sockets when doing MW elecsa happy with L-E N-E with Lim for L-N

too many hidded things to watch out for

new builds and CU changes different matter! however i had to limit L-N on my assessment CU change as customer had built in fridge and socket was located right behind!! no way i was doing test on his fridge plugged in!!

They're happy with this then? I wonder if NIC would be happy to just not bother with a L-N on lighting circuits? I have to do some work on commercial lighting circuits soon (16A) and the thought of having to remove 50 lights to test just seems ridiculous

 

[Sintra]

Our NICEIC accessor is happy to do L&N together to earth ins res on a minor works cert or a PIR as long as it is noted in the agreed limitations.

 

[elec1984]

Hi i'm new to this forum and have my elecsa assessment coming upina few weeks. I have a question about doing an insulation test on a radial circuit (domestic upstairs lights) i have tested the circuit and am getting a very low reading under 0.28 mohms. Anyone got any ideas why this is so low

 

[jamie-spark]

what type of wiring is it ?

what conductors are you testing between