106 ELECTRICAL AND MECHANICAL CHARACTERISTICS OF KENYAN CLAY SOILS AND THEIR SUITABILITY IN MAKING ELECTRICAL INSULATORS
Previous studies have shown that different types of clay soils exist in Kenya. With special interest is the huge presence of china clay in various localities, which can be used to make electrical porcelain insulators. Some of the localities with huge tonage of china clay are Eburru in Naivasha, Githu-ini in Karatina, Mukurwe-ini in Nyeri and Nunguni in Machakos. The study has shown that the amount of china clay in these localities is economical for production of electrical insulators. The chemical analysis also showed that the composition of clay soils from the four regions met the requirements for production of insulators. The current research study was carried out to test the electrical and mechanical properties of these clay soils. The electrical tests carried out were dielectric strength and loss angle tangent. The mechanical tests carried out were tensile strength, compressive strength and porosity test. Specimens were made from the clay soils by slip casting. The specimens were then fired at 1300oC. Specimens from Eburru in Naivasha, Githu-ini in Karatina and Mukurwe-ini in Nyeri had the required electrical and mechanical characteristics. Nunguni sample failed dielectric strength, loss tangent and porosity tests hence cannot be used to make porcelain insulators though it had good tensile and compressive strength. Therefore although most of the Kenyan clay soils are suitable for making electrical insulators, it is necessary to test both mechanical and electrical characteristics of samples from each locality to ascertain their suitability.