Surface creepage and high-voltage insulation

THE fundamental principle of designing high-voltage insulation, such as bushings, insulators etc., is obviously the application of electrostatics. A close examination of the evolution of the present methods of designing, however, will reveal the fact that it has been based very much upon experience rather than rational design. If the design were executed in rigorous accordance with the theory of electrostatics, the result would not necessarily be satisfactory, but very often lead to failure.