OP
Deleted member 9648
so on that basis then lets assume its a new install job......Multiple rod system or single?............
DNO to cover distribution circuits,and one rod for each final distribution board serving hookups...separated from DNO.
I do not subscribe to the multiple rods in order to achieve a very low Ra. My argument being that it is not practical to achieve a low enough and stable Ra for operation of an overcurrent device. IMO you are always going to be reliant on the RCD for earth fault protection on a TT,therefore what is the point in going to expensive lengths to get an Ra of say 5 ohms,which still will not be low enough for the overcurrent device...so you are still reliant on the RCD,therefore you may as well settle for <200 ohms with a single rod.
This is purely my opinion,and despite previous altercations on this subject...I accept that E54's view is equally valid.