will only test loop on high current

[martinh287]

Hi guys

Testing today large country manor house/mansion today and had a issue with getting loop reading on no trip on my fluke 1653 mft. could only get a loop reading on high current. I can physically see that the earth is connected and I have a voltage present.

The installation briefly compromises of 2 phases incoming linked at source to make 3 phases ( awaiting new substation and 3 phase feed from dno.) TT system ,60947-2 incoperating S type rCD. changeover switch( set on mains) mains panel with 8x three phase sub feeds.

Nowhere on this installation can I get a no trip reading. all I get is greater then 2000 ohms but yet acceptable readings on high current.

The sub mains I can test on high but when it came to the final circuit's (all rcbo protected) would be easier on no trip.

Easier or not I would still like to know why I am not getting a loop on no trip so any help would be appreciated

 

[martinh287]

No trip was tried at each Point and at a couple of the sub mains and still greater then 2000ohms

No trip was also tried with a different tester and same result.

 

[jaydee81]

what was your ze reading

 

[telectrix]

on a TT system it might be that the reistance is too high for the no-trip test to pass the low current.

 

[martinh287]

36.2 ohms ze