Fluke 1662/1663 issues

Wondering if anyone has suggestions, my company uses the 1662/1663 fluke mft. We’re have issues with readings, brand new leads and tester has come back from calibration with a pass.

When zero’ing test leads for continuity we zero live and PE lead together. Gives a zero value of 0.08. Which is expected. The issue arises when doing loop impedance test. The instructions state that zero must be done prior to RLO or loop impedance test as the zero doesn’t auto carry over like the meggers do. On the 1663/1662 testers you can only zero the leads on loop test with 3 leads together. This gives a zero value of 0.14. When testing the loop impedance my results are 0.06 lower than the other tester who is using a megger. As his tester is deducting 0.08 and mine is deducting 0.14. Not a big issue on lighting circuits etc but submains where results are low anyway my results are coming in at 0.04 and the meggers 0.10. This has been flagged in the office.
I’ve spoken to the calibration service and explained the above and they’ve told me they can’t see anything wrong with how I’m explaining the zeroing procedure and the zero reading I’m getting are what they would expect in there calibration.

So I’m completely stuck, tried to speak to fluke technical support but can’t get through to anyone. And two testers that give 0.06 difference can’t be okay as this effects PeFC massively at submains.

Anyone has similar or got any ideas?

what makes you think its the fluke that is wrong and not the megger? have you put your leads in the megger to see what resistance you get?

poni said:

what makes you think its the fluke that is wrong and not the megger? have you put your leads in the megger to see what resistance you get?

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It’s what a few people have said, basically the DNO supplier give us a reading of 0.10 incoming, the reading we get with the megger is 0.11, and the fluke is getting 0.05.

So the megger seems to be more “true”.

Not sure if anyone uses the fluke 1662 series. But am I mistaken in how I’m interpreting the instructions in terms of zeroing the leads for loop impedance? All 3 leads need to be zero’s together ( if you try and zero two leads L-PE only on loop test the leads show >3100ohm)
A few people have said they don’t zero for loop impedance on the fluke, but clearly states.