What are the implications of a failed Neutral - Earth insulation resistance test?

[markusjames]

Greetings!

Newbie here! We have 3 phase installation in our Lighting dimmer rack. During Insulation Resistance testing on Earth-Nuetral, readings was 0.33Mohm on 500v test. What causede the failed test and how can I troubleshoot? Thank you!

Markus

 

[Lucien Nunes]

At the moment, when you test N-E you are testing the supply cable, all the electronics in the rack, all the outgoing circuits, all the lighting fixtures powered by those circuits, literally the whole system at once. This is not a helpful test (unless it passes!)

Also, the manufacturers may not permit testing just N-E at 500V as this can put the test voltage across the output semiconductors. You must test in accordance with the manufacturers' instructions or you might damage the dimmers.

I can't add any more until you tell the model of the dimmer rack.

 

[markusjames]

At the moment, when you test N-E you are testing the supply cable, all the electronics in the rack, all the outgoing circuits, all the lighting fixtures powered by those circuits, literally the whole system at once. This is not a helpful test (unless it passes!)

Also, the manufacturers may not permit testing just N-E at 500V as this can put the test voltage across the output semiconductors. You must test in accordance with the manufacturers' instructions or you might damage the dimmers.

I can't add any more until you tell the model of the dimmer rack.

We are using
C21 DIMMING SYSTEM
please refer to the photo.
This system supplied by 3 phase power.

 

[goasis]

Why are you testing it??

 

[markusjames]

We are using
C21 DIMMING SYSTEM
please refer to the photo.
This system supplied by 3 phase power.

Why are you testing it??

Annual inspection to check the integrity of the system. We're checking the electrical installation.

 

[dmxtothemax]

it may be that there is an internal neutral to earth jumper in one of the dimer racks ?

 

[davesparks]

Are any of the connected loads part of ETCs source 4 range of products?
I've had problems with them having low IR to earth on a few dimmer system EICRs,