Testing IR with serge protection

[jamminuk]

Hi,

Just wondering how you would test IR when there is serge protection in the installation? Would it be a case of linking it out or reducing the test voltage?

Also why would a test for Zs trip RCD? :banghead:

Thanks again in advance

Ben

 

[IQ Electrical]

Hi,

Just wondering how you would test IR when there is serge protection in the installation? Would it be a case of linking it out or reducing the test voltage?

Also why would a test for Zs trip RCD? :banghead:

Thanks again in advance

Ben

You can test at 250V dc but the result must still be greater than 1MOhm.

The voltage is reduced to prevent the SPD from leaking to earth (as it should) at higher voltages.

As for the Zs test, think about the current that the tester is applying between L and E on an earth loop impedance test.

 

[La Poste]

You can test at 250V dc but the result must still be greater than 1MOhm.

Between which conductors?
Thanks.

 

[IQ Electrical]

Between which conductors?
Thanks.

Generally, you'd be able to test between all conductors at 250V dc but you'd still be subjected to the same constraints from other sensitive devices (ballasts etc.) that might mean you'd be testing with L+N combined to Earth.