The main function of the cable sheath is to protect the cable from the surrounding environment and to make it run safely. The main function of the cable insulation is to make the conductor in the cable insulated from the surrounding environment or adjacent conductors. The sheath is enhanced insulation, not included in the insulation value, and the sheath must be removed when measuring insulation.
The sheath material is the main function of the protective cable. Select sheath material according to external conditions, temperature, humidity, chemical environment and special requirements. The main function of insulating material is to provide protection for conductor insulation. According to the heating condition, useful life and special requirement of conductor, insulation material and temperature grade are selected. For example, common insulating material pvc.