What are the hazards of unqualified wires and cables?

Wires and cables are a large category of electrical products used to transmit electricity, transmit information and realize electromagnetic energy conversion. Wires and cables play an important role in all economic activities and social life. It can be said that wherever there are people living, wherever there are production, transportation and all economic activities, wires and cables are indispensable. Therefore, the quality of wires and cables directly affects our lives.

Unqualified products mainly have problems with structure, conductor size, conductor resistance, insulation and sheath tensile strength before aging. Consumers who use such products are prone to leakage, electric shock and even fire. These inferior products have buried many hidden dangers for the normal operation of the power system.

After a single-phase grounding (short circuit) accident occurs in the wires and cables, the relay protection device causes the wires and cables to overheat due to the failure of the last action to cut off the fault, resulting in spontaneous combustion of the insulation layer.

Wires and cables with qualified tensile strength and elongation before sheath insulation aging. Unqualified tensile strength and elongation of the insulating sheath before aging directly shorten the service life of the wires and cables. In addition, during construction or in an environment where power is on for a long time and the temperature is high, the insulator is prone to breakage, resulting in exposed live conductors and the risk of electric shock short circuits.

Wires with unqualified conductor resistance. Conductor resistance is mainly an important indicator for assessing whether the conductor material and cross-section of wires and cables meet the requirements. When the conductor resistance exceeds the standard, the loss of current passing through the line is increased, which aggravates the heating of wires and cables. The main reason for the unqualified conductor resistance is that in order to reduce costs, enterprises shrink the copper material, which accounts for 80% of the raw material cost, either by reducing the cross-sectional area of the conductor or by using recycled copper with too high impurities. This causes the conductor resistance of wires and cables to seriously exceed the standard. In the process of use, it is not only easy to cause fires, but also accelerates the aging of the insulation layer wrapped around the wires.