IR Testing on domestic installations.

[electek]

Hi All ,
When testing insulation resistance on a domestic lighting circuit do you just join live/neutral and test down to earth otherwise if your testing live to neutral presumably you have to close all switches and remove all the lamps in the circuit.

Thanks Chris

 

[electek]

Sythai , Yep , let me know mate - good luck hope all goes well

 

[nickblake]

elect yes it is , im a funny bugger like to do them seperate

 

[Des 56]

An insulation resistance test is done over the whole of the installation
It needs to be done on individual circuits only when a problem may exist

 

[electek]

Des 56 , yep , i'm aware of that but i was wondering how you would do IR test on a lighting circuit if asked to do so on the actual part 'p' assesment ?

Regards
Chris

 

[Risteard]

An insulation resistance test is done over the whole of the installation
It needs to be done on individual circuits only when a problem may exist

And if it is done on circuits individually then calculations would need to be done to ensure that the installation is satisfactory, i.e. 1/Rt = 1/R1 + 1/R2 etc.

The values in BS7671 relate to the installation/dis. board - not to individual circuits!

 

[WayneL]

And if it is done on circuits individually then calculations would need to be done to ensure that the installation is satisfactory, i.e. 1/Rt = 1/R1 + 1/R2 etc.

The values in BS7671 relate to the installation/dis. board - not to individual circuits!

Are you saying that if you IR tested six circuits individually, and they each gave a reading of 5 M ohms, the installation wouldn't comply, and you would fail it.

 

[Risteard]

Are you saying that if you IR tested six circuits individually, and they each gave a reading of 5 M ohms, the installation wouldn't comply, and you would fail it.

If below 2 Megohms then you would need further investigation, i.e. checking individual circuits. You already have the values for the individual circuits.

The point I was making was that the insulation resistance value is not just fo the circuit (read the Regulation carefully).

 

[WayneL]

If below 2 Megohms then you would need further investigation, i.e. checking individual circuits. You already have the values for the individual circuits.

The point I was making was that the insulation resistance value is not just fo the circuit (read the Regulation carefully).

I know, I'm just causing trouble - that's why the big cheesy grin

It's an interesting scenario, though, 'cause it gives an overall resistance of 0.83 Mohms for the installation, yet each individual circuit complies.