Unqualified products, the main problem lies in the structure, conductor size, conductor resistance, insulation and sheath tensile strength before aging, consumers use such products, prone to leakage, electric shock and even the risk of fire, these inferior products to the normal operation of the power system buried many hidden dangers.

After the single-phase grounding (short circuit) accident of the 1. wire and cable, the wire and cable overheating caused by the failure of the relay protection device to cut off the fault, resulting in spontaneous combustion of the insulation layer.

2. wire and cable with qualified tensile strength and elongation before sheath insulation aging. The unqualified tensile strength and elongation of the insulating sheath before aging directly shorten the working life of the wire and cable, and in the construction or in the environment where the power is energized for a long time and the temperature is high, it is easy to break the insulator, resulting in the live conductor Exposed, the risk of electric shock type short circuit occurs.

3. wires with unacceptable conductor resistance. Conductor resistance is mainly an important indicator for assessing whether the conductor material and cross-section of the wire and cable meet. When the conductor resistance exceeds the standard, it increases the loss when the current passes through the line, and aggravates the heating of the wire and cable. The reason for the unqualified conductor resistance is mainly that in order to reduce the cost, the enterprise shrinks the copper material, which accounts for 80% of the raw material cost, either reduces the cross-sectional area of the conductor or uses recycled copper with excessive impurities, thus causing the conductor resistance of the wire and cable to exceed the standard seriously. In addition to easily causing fire in the use process, it will also accelerate the aging of the insulating layer wrapped in the wire.

4. wire and cable insulation in normal operation will gradually aging, its service life is generally 15-20 years, if the wire due to the use of time often overload or overvoltage, plus the insulation layer thickness is not up to standard, improper installation (such as the bending radius of the cable is too small, wire protection pipe diameter is small), etc., are likely to cause accidents.

5. the wire and cable with unqualified structure size. The main problem of the structure size is the sheath thickness, insulation thickness, when the cable sheath and insulation thickness is not up to standard, resulting in wire and cable resistance to electrical strength will be seriously reduced, resulting in wire and cable life is shortened, serious can lead to wire and cable breakdown, insulation (sheath) layer can not play a normal protective role, resulting in electrical short circuit and fire and other phenomena.