Study of Soil Specific Resistance

Abstract

The purposes of this research were to: 1) investigate the soil resistivity of loam soil, clay soil, sand soil, shale soil and sandy soil and 2) identify the appropriate grounding system for the design of the earth core system by using parallel ground and delta ground. The measure tools consisted of a soil resistivity meter model KYORITSU 4105 A with a soil rod of a 0.012 m diameter. A grounding rod with a length of 2.40 m was used to measure the soil resistivity of the grounding system of various soil types such as loam, clay, sand, shale and sandy. Then, the soil resistivity of the measured grounding system was calculated to find the specific resistivity of the soil. After that the specific resistivity of this soil was used to calculate the soil resistivity when using the grounding rod of 2.40 m.

The results revealed that there were two types of suitable grounding system namely parallel ground and delta ground. The calculation of parallel ground is based on data in the table of the Council of Engineers Parallel Ground Resistance Reduction Multiplier.  It can be seen that the loam soil is selected with parallel ground using 2 soil stakes 2.40 meters long; the clay soil using parallel ground using 2 soil stakes 2.40 meters long; the sand soil using parallel ground using 2 soil stakes 2.40 meters long. Parallel ground uses 2 2.40 meters long soil rods. The two types of grounding system were not chosen for the sandy soil because the resistance values ​​of both types are greater than the standards set by the Provincial Electricity Authority (PEA).