Dead Short

What are you units?


I'm guessing the IR test results are in MΩ - so 0.00 could mean anything below 0.0099' MΩ (or 0.005MΩ if your meter rounds off) - 0.009 999MΩ = 9,999Ω and would only let about 23mA pass at 230V - which isn't likely to upset anything much.


Next question - which pairs were insulation tested? L-N or L-PE (or L-L)? If L-N (or L-L) then if the loads were connected you should expect a very low reading (and possibly damaged loads...)


  - Andy.

As Andy says above, it sounds like there is a load connected. Even a PIR/photocell sensor will give a very low IR reading.


I was called to do remedials on a warehouse, - 'Lighting circuits do not pass Insulation tests'.

It was 3 banks of old fluorescent lights, when inspected, they all had a capacitor (snubber?) between L+N, thus low IR readings. The previous Inspector clearly had not enough experience to know this was likely to be the fault.

And presumably large enough caps to need a bleed resistor in parallel to make them safe a few seconds after switch off.


Genset wil probably work just fine into a ste up with an NE short, and no point in measuring L-N or L-L unless all loads are removed.

The light fittings are all 500w tungsten and the photo cell was removed.

The test were carried out on L-N , L-E and L-L.

With the lamps still in??

Yes there are 42 posts with 2 lights on each.

also 3 cable runs underground with 3phases to each pole.

So a L-N & L-L insulation test was done on a network of 500W halogen fittings with the lamps still in place?

L-E 

Ok..... so L1- E & L2-e & L3-E all show 0.00 on meg scale?


What about N-E?