3.1　Hard Insulating Tools

Among the hard insulating tools,the most widely used are insulating rods,as well as insulating platforms and insulating hard ladders made of insulating tubes or plates.Insulating rods are divided into insulating bars,insulating struts and pull rods(hangers)according to the application and operation method.In addition,insulates cross arms and insulated insulator cradles are also frequently used as hard insulating tools.Hard insulating tools are basically made of glass fiber boards or fiber glass epoxy plastics.In particular,fiber glass epoxy plastics(referred to as FRP)are made from glass fiber and epoxy resin.Because of the excellent electrical insulation properties of glass fiber and epoxy resin,the glass fiber reinforced plastics have excellent mechanical and electrical properties.(https://www.daowen.com)