3. Cables with unqualified insulating sheath materials. […]
3. Cables with unqualified insulating sheath materials. Insulation and sheathing ensure the normal operation and service life of the cable. Failure of the insulation and sheath material will accelerate the aging of the cable and reduce the tensile strength and mechanical strength of the cable. Insulation during the construction process or in a long-term and high-temperature environment is prone to breakage, resulting in the risk of electric shock short circuit in electrical equipment. The main reason for its failure is the use of recycled materials in the production process to reduce product costs. Second, the production units do not have production capacity and production qualifications.
4. Cables with unqualified conductor resistance. The conductor resistance is mainly used to test the conductor material of the cable and whether the cross section meets the important criteria of the standard. When the conductor resistance exceeds the specified value, the loss of the current on the line is increased, resulting in the occurrence of heating problems of the wire and cable. The reason for the failure of the conductor resistance is mainly because the production unit is greatly reduced in the conductor material in order to save the production cost, and some inferior conductors are used, so that the conductor resistance of the produced wire and cable is seriously exceeded, and it is easy to cause fire in the work operation. It also accelerates the aging of the insulating layer that is wrapped around the wire.