Evaluation of contamination resistance of GFR epoxy rods for indoor application by means of a salt fog test

GFR (Glass Fibre Reinforced) epoxy insulators are very useful where both mechanical and electrical stress are to be endured. Outdoor applications are e.g. suspension insulators in overhead lines and hollow insulators for cable terminations and bushings. Indoor applications can be found in switch gear in the form of support insulators or pull rods. The present paper focuses on indoor applications in particular. Discussed are: the equipment and possible environmental impact, the kind of degradation to be expected, principles of fog tests, the application of fog tests to rank materials and finally a discussion of the results.