An electrical assembly, such as an insulator or a surge arrester, utilizing a pair of end collars for coupling an elastomeric weathershed housing to a pair of metallic end fittings, and for reducing electrical stress at the interface of the ends of the weathershed housing and the end fittings, and for sealing the ends of the weathershed housing to the end fittings. In particular, a radially directed force is applied to the weathershed housing by insertion of the core member into the axial bore of the weathershed housing causing radial outward expansion of the weathershed housing into intimate contact with the end collars. Also, each of the ends of the weathershed housing is held in contact against the inner end of the respective end fitting to seal the interface therebetween. Accordingly, a watertight seal is created at the interface between each of the end fittings and the ends of the weathershed housings. The end collars are electrically and mechanically coupled to the end fittings via either a press fit or a set screw for reducing electrical stresses at the interface of the ends of the weathershed housing and the end fittings. The core member can be an insulating rod or a plurality of electrical components, such as metal oxide varistors.