This technical specification applies to hybrid insulators for a.c. and d.c. applications consisting of a load-bearing insulating solid or hollow core consisting of ceramic or glass@ a housing (defined geometry@ outside the insulating core) made of polymeric material and end fittings permanently attached to the insulating core. Hybrid insulators covered by this technical specification are intended for use as suspension/tension line insulators@ line post insulators@ station post insulators and hollow core insulators for apparatus. The object of this technical specification is to: ? define the terms used; ? prescribe test methods; ? prescribe acceptance criteria. Silicone or other functional coatings (CIGRE Technical Brochure No. 478@ Appendix B)@ booster sheds@ shed extenders and rain deflectors are not within the scope of this technical specification. This technical specification does not include requirements dealing with the choice of insulators for specific operating conditions.