High(ish Zs and extending ring final question.

[Marcus Vaughan]

Sometimes you do get a “high” Zs reading when testing a circuit with an RCD. I’ve had this happen before and out of curiosity have bypassed the RCD or put the lives into the non RCD side, and the results have been a lot lower.
As the others have mentioned, do the ring dead tests and that will highlight any connection issues.

Thank you - seems to be the consensus.

 

[Marcus Vaughan]

Id rather fit a used MCB to match the cu that start fitting another make. Just make sure your quote and invoice state a used part will be fitted ........

Good advice that. I’m wondering if bus bars have been hacked about or not secured particularly well. Something to look forward to!

 

[Marcus Vaughan]

Well - that's the end if that thread. We'll never know. Customer called me at 5pm the night before to cancel the job. 'Cost outweighs the benefits'. I'd kept the day free for it as well - so ended up grovelling around in the phone in the evening to bring jobs forward.

I did let the customer know that 'Further Investigation' was still recommended (an extra sockets and 5 or 6 metres of cabling would only have made the Zs slightly higher).

Grrrrrrrr.

Thanks for posts everyone though - I have learnt something ready for next time.