1、 The DC resistance of the conductor exceeds the standard: The copper wires of wires and cables should be made of high-purity electrolytic copper, so that the wires drawn out are average and glossy. Some consumer enterprises that use recycled copper to achieve high profits or cut corners to reduce the copper area, resulting in serious exceeding of wire conductor resistance.
2、 The insulation and sheath materials should have appropriate mechanical properties (tensile strength, elongation at break). If the indicators are not qualified, the insulation and sheath materials of local wires and cables should use recycled plastic, but their tensile strength and elongation at break cannot meet the application requirements. The mechanical process of cable breakage and bare charged conductors can lead to short circuits and leakage discharge.
3、 The insulation thermal extension project of high-voltage cables is not qualified: some products have shown fusing phenomenon in the insulation thermal extension, which can easily cause short circuit accidents under high temperature conditions.
