Alternative materials can provide many benefits when applied to utility structures. Two materials that are being considered as alternatives to traditional steel and wood are ductile iron and fiberglass reinforced polymer (FRP), alternatively called composite. There is a need to fully understand the material attributes as well as failure and degradation modes, particularly at high voltage. Despite continuing refinements in material composition and manufacturing techniques, these products have a comparatively short history in electric utility service. The research objective is to increase knowledge of the utilization of ductile iron and composite structures by providing engineering groups with the information needed to specify and evaluate the technology, and recommendations for its subsequent application.