IEC 60507 Ed. 2.0 b:1991

Is applicable for the determination of the power frequency withstand characteristics of ceramic and glass insulators to be used outdoors and exposed to polluted atmospheres, on a.c. systems with the highest voltage of the system ranging from 1 000 V up to 765 kV. These tests are not directly applicable to greased insulators or to special types of insulators (insulators with conductive glaze or covered with any organic insulating material).