zs on lighting circuit does breaker need to be on

[DaveS]

If drove u made by now apologies. Written exam Tues. Getting confused by books/vids.... will I get an exceptable zs reading with breaker off at when testing end off lighting circuit (last lighting rose cpc/switch return) as some show with breaker on some off. Cheers

 

[Leesparkykent]

If drove u made by now apologies. Written exam Tues. Getting confused by books/vids.... will I get an exceptable zs reading with breaker off at when testing end off lighting circuit (last lighting rose cpc/switch return) as some show with breaker on some off. Cheers

The earth fault loop impedance test is a live test so obviously the MCB would have to be on.

 

[ImpededLoop]

The earth fault loop impedance test is a live test so obviously the MCB would have to be on.

As Lee says, although there is a method where you can test Zs at the DB with a link at the end of the circuit to avoid tripping rcd's.

For a C&G exam it should be a live test.

 

[DaveS]

That's what I thought Lee : ) but reading Kitcher testing book he's doing a Zs test on radial socket and clearly says isolate circuit. Confwwusing

 

[Leesparkykent]

That's what I thought Lee : ) but reading Kitcher testing book he's doing a Zs test on radial socket and clearly says isolate circuit. Confwwusing

https://m.youtube.com/watch?v=vtZpe4_Go78

 

[Leesparkykent]

The method in the book you a reading is a way of measuring Zs using the high current setting without tripping the RCD. As impeded loop said in #3 for the purpose of the exam it should be a live test.

 

[DaveS]

Cheers guys really appreciated. Just trying to be sure. Although sounding very thick in process : ) passed multiple choice anyway 36 out of 40 so hopefully be ok

 

[Leesparkykent]

Cheers guys really appreciated. Just trying to be sure. Although sounding very thick in process : ) passed multiple choice anyway 36 out of 40 so hopefully be ok

Happy days not a bad result at all then. It was a method more commonly used when testing Zs on a circuit protected by a an RCD when testers didn't really have the low current setting.

 

[davesparks]

Happy days not a bad result at all then. It was a method more commonly used when testing Zs on a circuit protected by a an RCD when testers didn't really have the low current setting.

It is still a very useful method if you are testing the outgoing circuits of an installed stage lx dimmer.