IR testing with a full load?

[Eugene Herbst]

Hi all,
I'm sure this question has been asked before but just can't find it.
When doing the IR test on a 3phase commercial board, how do you go about testing the circuit if there are items that just can't be disconnected, ie Bank of lights or immovable equipment, is there a trick to doing this?
Have the same issue with domestic single phase boards and high ceiling downlights!

Any advice would be much appreciated, TIA

 

[westward10]

Is this an EICR.

 

[Eugene Herbst]

Is this an EICR.

Yes it is

 

[westward10]

Whether single or three phase you follow the same principle connect line and neutral together then test to earth.

 

[Eugene Herbst]

Whether single or three phase you follow the same principle connect line and neutral together then test to earth.

That's what I've been doing by way of a "piggy back lead" on my megger mft 1721, but get unsatisfactory results. I have also confirmed this by testing with a load on the circuit (oven circuit)...unsatisfactory, then taken the load off and voila satisfactory.

The problem is I'm getting handed more & .more EICR'S where I can't remove the loads, especially in commercial settings!

 

[westward10]

What are the unsatisfactory results, don't forget on a periodic you aren't looking for perfection.

 

[Eugene Herbst]

What are the unsatisfactory results, don't forget on a periodic you aren't looking for perfection.

0.09M.ohm very much unsatisfactory

 

[littlespark]

Most commercial loads should have a local isolator. Turn it off and test to there.

domestic eicr forms have a box to list equipment likely to be damaged due to IR testing…. LED lights, smoke detectors etc. Just have to note as a limitation.

 

[westward10]

0.09M.ohm very much unsatisfactory

In this instance it is what it is. I tend to have a quick look but all you can do is Code it in the Report. There is little which should affect an IR test unless you have a genuine fault whether this be the cabling or a light fitting but rcd sockets and spurs can, filtered equipment will normally test clear at 250v.

 

[HappyHippyDad]

As above.
This is most probably a fault. You're not doing anything wrong, it gets coded and then it's up to the client to get it fixed.
You just cant feasibly disconnect everything, therefore L/N - E IR test, as you are doing.