Action to be taken if you get an unsatisfactory reading

[trevmai]

What should you do if you get an unsatisfactory Zs reading??

Any help welcome!

 

[securespark]

Depends.

If it's due to a high Ze, call the DNO.

 

[trevmai]

DNO?

 

[plugwash]

First things first you should measure Ze, if Ze is above 0.8 for a TN-S or 0.35 for a TN-S its time to complain to the supplier.

once you know Ze is ok then its time to go back over your design calculations ,check for bad joints and test that the resistance of cables is what it should be until you find the problem.

but if this isn't obvious to you then it's imo a sign that you aren't really competant to be doing electrical design/installation work.

 

[RF Lighting]

DNO?

DNO = Distribution Network Operator

//wiki.diynot.com/electrics:other:dnomap

 

[comms]

Not forgetting that if you have a TT system you will have a high Zs on circuits.

Check Ze is ok (as others have said) if it's ok how about the use of a rcbo or rcd as one option.
But you should find the reason for the high reading.

 

[Spark123]

iirc on some RCBOs the RCD aspect is unsuitable for use for protection against indirect contact, they need to operate in their overcurrent mode. (something to do with the RCD electronics requiring a certain amount of voltage to remain effective.)