There are several other voltage surges that can add to the continuous stress exerted on electric insulation in an energized system. Among these are lightning, static charges, switching surges, physical contact with a higher voltage system, amplified voltage effects in series inductive-capacitive circuits, auto-transformer connections, and repetitive re-strike or intermittent grounds.
Over-voltages should be curbed as much as reasonably possible. Additional insulation may be the best solution, but entails the obvious disadvantages of increased cost, increased size and weight, and decreased heat rejection from the current-carrying conductors. Therefore, the conductors are likely to heat to higher temperatures at the same current flow levels. There are also many design principles which the application engineer can use to curb the magnitude of over-voltages.
