Surface resistance measurements on nonceramic insulators

The results and analysis of surface resistance measurements performed on nonceramic insulators (NCI) are presented in this paper. The goal of this study was to determine if the surface resistance measurement procedure can be formalized to ensure repeatable and reproducible results. The NCIs evaluated had housing materials made from one type of silicone rubber and one type of ethylene propylene diene terpolymers (EPDM) rubber. A porcelain post insulator was used as a reference. The Task Force concluded that it is possible to establish a standard for surface resistance measurement in the laboratory. Such a standard is valuable since surface resistance provides: (1) an indication of aging on NCI housing material, and (2) a more sensitive indicator of true contamination severity on insulators than provided by conventional ESDD (equivalent salt deposit density) measurements. As a first step in this direction, guidelines for measurement have been provided in this paper. Suggestions for future work needed for standardization are also included in the paper.