TT sytem - is a Ze alone acceptable?

[IAmSparkytus!]

Evening!

When testing a TT system with a single earth rod, is it acceptable to take a Ze reading rather than an Ra reading?

Thanks.

 

[telectrix]

yes. but if the Ze is too high for ADS, RCD/s for fault protection will be required.

 

[Strima]

Ze test is an acceptable method as mentioned in Guidance Note 3.

 

[Rockingit]

There multiple examples of when you literally can't mechanically perform an Ra test even if you'd want to, so Ze is perfectly acceptable.