In previous articles Single Earth Electrode and Earthing Resistance Calculation, I have presented methods of calculating the earth resistance using IEEE or IEC methods.

AS 1768 Appendix C recommends that the resultant earthing resistance may be calculated by using the ordinary equation for resistances in parallel if the separation between earthing electrodes is greater than the electrode length. It also added that for practical purposes, the separation between vertical earthing electrodes can be taken as twice the length of the earthing electrode.


  • A Filipino Engineer, Registered Professional Engineer of Queensland (RPEQ) - Australia, and Professional Electrical Engineer (PEE 2574 - 1st Place April 1991) - Philippines with extensive experience in concept selection, front-end engineering, HV & LV detail design, construction, and commissioning of Hazardous and Non-Hazardous Area electrical installations in water and wastewater pipeline and pumping facilities, offshore platforms, hydrocarbon process plants and pipelines including related facilities. Hazardous area classification and design certification (UEENEEM015B, UEENEEM016B, UEENEEM017B).


Comments are closed