I — Insulator arcovers versus size and humidity

DATA covering the electrical characteristics of comparable insulators as received from different sources frequently are conflicting. In an attempt to clarify some aspects of this controversial subject, a study has been made to establish rules whereby such characteristics can be estimated from the dimensions of the insulators with a reasonable degree of certainty. Variations in the arcover potential of dry insulators due to the influence of humidity changes also are considered and approximate correction ratios given.