Outdoor insulator surface conductance and surface arcing

This paper is the second in an expected series of papers dealing with the problem of evaluating wet surface conductance and its effects on insulators and insulation in outdoor and simulated outdoor conditions. During rain and dew and fog insulators are wetted, and their surfaces become conducting in varying degree. Measurements of insulator surface conductivities in the Pittsburgh, Pennsylvania area outdoors and in salt fog chambers were described in the first paper of this series.¹ In this paper, the investigation has been extended to evaluating surface conductance levels at various U.S. locations and under different types of precipitation conditions.