Problems with Zs (and possibly Ze and PFC) Using Megger MFT1553 Tester

[AMC]

Have just completed a consumer unit change, Ze is reading at 0.09, PFC reading at 9.5kA, Its on a TN-CS System and about 150m from nearest transformer. I am not highly experienced in Testing, and unable to establish what is going on, but I am suspecting there is a big problem! I am using a Megger MFT1553, which is also tripping internally (as in displaying 'trp on the tester) when trying to carry out Zs tests across all circuits using the 'no trip' function. Any ideas???

 

[AMC]

I have also tested the circuits using my Megger LT320 and it is displaying 'CHK'
Also have taken both Meggers to another house to eliminate equipment failure and both are functioning correctly.

I am panicking as the job is for my first ELECSA inspection next week!!! HELP!!

Im hoping its just my lack of experience missing something very simple!

 

[Sintra]

When using the no trip function all 3 leads must be used. Make sure you have a good connection on all 3 for the full duration of the test. Can't see the Ze reading being of any relevance. Are all your R1 + R2 readings ok?

 

[WayneL]

Have just completed a consumer unit change, Ze is reading at 0.09, PFC reading at 9.5kA, Its on a TN-CS System and about 150m from nearest transformer. I am not highly experienced in Testing, and unable to establish what is going on, but I am suspecting there is a big problem! I am using a Megger MFT1553, which is also tripping internally (as in displaying 'trp on the tester) when trying to carry out Zs tests across all circuits using the 'no trip' function. Any ideas???

Hi mate,

I've got the same meter(1552) - the only time I've ever had this message was when I (foolishly) forgot that the no-trip loop test was a three lead test

I'd been trying to test with the two leads and it came up 'trp' each time.

 

[WayneL]

Snap

 

[JUD]

I concur.

This is from the 1553 instruction manual.

 

[AMC]

Thanks for the replies, I have managed to get a Zs reading on my ring mains (using the 'plug' test lead) Im not sure why is it giving me a reading now, as before it was just stating 'trp' on the tester and not knocking out the RCD's. however, I have tried using the 3 lead method on my lighting circuits, as above, but it is knocking the RCD's out now! (I have been able to obtain a reading on my cooker radial using the 3 lead method though) Hmmmmm.....