No trip Zs tests

[morph]

thats fine
read the book it came with it gives tolerances , its cool beans man

 

[Deleted member 9648]

Did a series of tests today on a non rcd protected socket with the new megger ELI tester.....on high current setting 5 tests produced 5 identical results..0.13 ohms.
5 tests on no trip setting gave these results,
0.17
0.21
0.14
0.12
0.06
Not an acceptable level of consistancy on no trip setting IMO.....the meter has been returned to megger under warrenty,will keep you posted.

Update.....
Tester came back yesterday and I tried it on the same socket and got very similar results on the no trip setting.
Contacted megger again who pointed out that in Gn3 it states that loop testers cannot be relied on to be accurate where the Zs is under 0.2 ohms. This was not something I was aware of so checked Gn3 and sure enough it is there....(every days a school day).
The obvious next step was to try it out on a socket with a higher Zs which produced much more consistent readings....although still not as consistent as the high current test.....we did a series of test and one thing that was apparent was that on no trip a percentage of the tests produced random results.....
High current tests produced a consistent 0.36 ohms.....no trip produced fairly consistent readings between 0.30 and 0.38.....but one test gave 14.8 ohms(!)....and another 0.78...........I think on no trip I will get into the habit carrying out each test twice,as long as they are ballpark that will be good enough.
Hope this helps others concerned with the accuracy of the no trip function.

 

[IQ Electrical]

Wirepuller, I have a method to lift the tester into it's accurate 'sweet spot' also works on supplies in close proximity to the transformer where accuracy is very important for accurate PFC measurement.

I'm out on-site now but I'll post it up later.