The basic role of high-voltage insulators is to ensure proper attachment of the line conductors to grounded support structures. In this respect, the insulators play two essential roles:

1. To ensure the electrical integrity of the system, under diverse weather conditions, by withstanding electrical stresses associated with system voltage as well as related temporary and switching overvoltages. While flashovers due to direct lightning strikes cannot be practically eliminated, these can certainly be managed down to acceptable levels.