Composite Suspension Insulator is also known as “composite long rod insulator” The term ‘‘long rod’’ is actually used for a specific design of porcelain insulator which was first introduced in Germany in the 1920s as an alternative to cap-and-pin insulators (and also for critical ambient conditions, for example high pollution). The construction of a composite long rod is shown in Fig. The fiber reinforced core, the metal fittings and the silicone housing can be seen.