problems with Zs testing

[DDnot]

Hi!

I was measuring Zs on a lighting circuit some time ago. First I did R1+R2 and it was around 1.60, pretty high but there were a few connections on the way and most of the cable was 1.0mm. Ze measured at the CU was low about 0.10 only, so Zs altogether around 1.70. When I measured it using Zs option on my tester Zs was only about 0.60. I know that there usually is a little difference but it should not big that big. Can you help me and tell me where possibly I was making a mistake? Thanks in advance.

 

[telectrix]

parallel paths???? also, MFTs are not renowned for accuracy on no-trip testing.

 

[Redvanman]

That's why loads of guys calculate zs

 

[Landril]

You just reminded me Tel i need to put my MFT in calibration...at least £100 down the drain

 

[jamesBoater]

Have found this alot where the Zs does not tally up with Ze + R1+R2 readings, i expect it it caused by parallel paths. Bonding perhaps

 

[telectrix]

You just reminded me Tel i need to put my MFT in calibration...at least £100 down the drain

about £60 using OSCS, and he comes to you.