The research on soil characteristic by measuring soil resistancy and resistivity is an important factor to make a good grounding impedance. The optimal evaluation and planning of the grounding system can be achived by understanding the soil structure and characteristic. The soil resistivity varies upon soil composition, temperature, water content and its chemical content. In this research we analyse soil characteristics of the samples from Madiun and Surabaya areas by conducting some physical treatments such as water, salt, and carbon treatments. These samples then area tested using OHz-15MHz frequency from sinusoidal power supply. Generally, soil impedance has a negative correlation upon addition of water and salt content, but has no correlation upon additional carbon content. Keywords: soil resitance, soil resistivity, grounding resistance, grounding system. Bambang Anggoro, Ngapuli I. Sinisuka, Parouli M. Pakpahan, dan Dicky Irman B. E-mail: bambang@hv.ee.itb.ac.id
