TT High Zs

[davesparks]

Good points....I wonder how compliance with that regulation could be verified on an EICR? It would be very difficult to gauge the depth of an electrode without digging it up!

Simple, it's exactly the same as checking any other test results on an eicr. Measure the value and compare it to the previous test results, then you can assess any change which may have occurred.
After all one of the fundamentals purposes of carrying out tests and recording the results is to identify changes and trends in changes of the results in order to predict and prevent failures and identify maintainence requirements.

 

[Deleted member 9648]

Yep...assuming there is a previous EICR!

 

[David M]

If the value of the Ze is above the 200 ohms set by the guidelines but below the maximum permitted value of 1667,ensuring additional protection is correctly installed and operational (RCD) and thus compliant, the installation is perfectly safe to use.

I think a C3 would be reasonable code to note on the EICR. As a value greater than 200 would in theory require further investigation to ascertain stability.

One way to achieve this would be to test the Ze over a period of time under different environmental conditions and then compare the results. I doubt any of us would be in a position to do such monitoring, let alone the cost of such.
So one simple less costly solution would be to install additional rods... to try and achieve a value much less than 200 ohms.