1.2.1 Common Insulating Materials
For insulating material,under a certain voltage,only a tiny leakage current can pass through,so the insulation resistance value is large.The quality of insulating materials is directly related to the safety of live working,so the insulating materials for making tools for live working must be materials with excellent electrical performance,high mechanical strength,light weight and low water absorption,and must be aging-resistant and easy for processing.
At present,insulating materials used for tools and instruments for live working in China are mainly as follows.
(1)Insulating board.Including hard board and soft board,classified as laminated products,such as 3240 epoxy phenolic glass cloth board,PVC board and polyethylene board in engineering plastics,etc.
(2)Insulating pipe.Including hard pipe and hose,classified as laminated products,such as a 3640 epoxy phenolic glass cloth pipe,and rolled products like belt or silk.
(3)Plastic film.Plastic films such as polypropylene,polyethylene,PVC,polyester,etc.(https://www.daowen.com)
(4)Rubber.Natural rubber,artificial rubber,silicone rubber,etc.
(5)Insulating rope Rope woven by natural silk and artificial synthetic fiber,such as nylon rope,cotton fiber rope and silk rope(divided into raw silk rope and boiled-off silk rope),including stranded and woven round rope and ribbon woven rope.
(6)Insulating oil,insulating paint,insulating adhesive,etc.
According to the maximum allowable operating temperature of electrical equipment,i.e.heat resistance grade,International Electrotechnical Commission(IEC)classifies insulating materials into seven grades,i.e.Y,A,Z,B,F,H and C,with allowable operating temperatures of 90°C,105°C,120°C,130°C,155°C,180°C and above 180°C.