Wire and cable is used to transmit power engineering, transmit data and establish electromagnetic induction heat transfer a large class of electrical products. If a lot of unqualified goods are found in the course of sampling inspection, this kind of shoddy goods has buried many security risks for the normal operation of the power supply system. Let me analyze the reasons and common problems of unqualified wire and cable for us.
1, marking the unqualified wire and cable mark is the specific method of identifying the basic information of wire and cable products. According to the standard, the important content of the identification is: product specifications, specification models, standard numbers, enterprise names, origin and so on in a certain identification section. When the mark is unqualified, it will lead to incorrect identification of the construction team, and it is likely to cause electrical equipment safety accidents when it is more serious
2, the main problem of the size of the structure of the wire and cable with unqualified specifications is the thickness of the sheath and the thickness of the insulation layer. When the sheath and insulation layer of the wire and cable are not qualified, the electrical impedance compressive strength of the wire and cable will be significantly reduced, and the service life of the wire and cable will be reduced. When it is more serious, it can cause the wire and cable to be penetrated, and the insulation layer (sheath) can not achieve the normal maintenance effect, resulting in short circuit failure of electrical equipment and fire accidents.
3, sheathed insulation before aging tensile strength, elongation of the wire and cable standards. The compressive strength and elongation of the insulation layer sheath before aging are not qualified, which immediately greatly shortens the service life of the wire and cable, and in the operation process or long-term plug-in high temperature conditions, the cable sheath is very easy to break, causing the conductor to be exposed to the outside, and the risk of electric shock accident short circuit failure. The primary factor for its failure is the application of recycled particle manufacturing to reduce production costs, and the second is not a small and medium-sized enterprise with manufacturing qualifications.
4, conductor resistance unqualified cable conductor resistance is mainly to evaluate the conductor raw materials and cross section of wire and cable is not suitable for the main index value. When the conductor resistance exceeds the standard, the current flow increases according to the loss of the route, which aggravates the hot wire and cable. The primary factor of conductor resistance failure is that in order to better control costs, the company will shrink the copper material, which accounts for 80% of the raw material cost. Either reduce the cross section of the conductor, or apply too much recycled copper residue, resulting in the conductor resistance of the wire and cable is more serious than standard, in addition to the easy to cause fire accidents in the whole process of application, it will continue to accelerate the aging of the cable sheath covered in the cable line.
