Zs reading sky high....

[Teddy54]

Hi Iam working on an outdoor public toilet and my zs readings to the circuits are in the range of 62 to 68.5 ,wereas on other simalir units it's been 0.5 - 0.7 . I have ensured all terminations are tight and belled out all circuits to ensure proper earth. It's a tns system. My ze PFC are fine. Any suggestions on what could be causing such a high reading?

Regards
Teddy

 

[malcolmsanford]

How are you taking this Zs by measurement I guess.

Is there an RCD on the circuit and could you be getting a false reading via the soft test.

You could also be getting a false reading if doing the full Zs no trip test through an high impedance of an MCB.

Personally I would do an R1 + R2 on the circuit to see what that is telling me. If that is within the expected levels, then test re-test with another type of MCB in the circuit.