Grounding (or earthing) play the main role to in order to protect electrical equipment, building and life from lightning, switching and earth fault occurrences. A good grounding system must be able to dissipated this unwanted charge in very fast time and this can be achieved by reducing the grounding resistance. Introduction to backfill material to be filled into grounding pit is widely implemented in order to lowering the resistance of grounding system. This paper investigates the performance of marconite, cement and sand as part of backfill materials for ufer type grounding system under alternating high voltage and impulse voltage condition. The purpose of high impulse voltage experiments is to determine the performance of above said materials under transient condition while the alternating high voltage experiment to observed the behaviour backfill material under leakage or fault current occurrence. The findings reveal that performance of grounding system may significantly change from the expected result at design stages.
