Pay attention to the most popular wires and cables

2022-07-27
  • Detail

When buying wires and cables, it should be noted that in the recent high efficiency period, Harbin market supervision and Administration Bureau conducted a quality sampling inspection on the wires and cables sold in the urban area. The test results showed that the quality of 8 batches of wires and cables such as "binyan" sold by Futai electric building materials sales department in Daowai District of Harbin and other merchants was unqualified, and the unqualified items were "conductor resistance at 20 ℃. The purpose of this project is to test whether the resistance of the conductor core of wires and cables exceeds the specified value of the standard. If the project is unqualified, it will accelerate the insulation aging of wires and cables, shorten their service life, and in serious cases, it will cause fire and threaten the safety of people and property

the wires and cables sampled this time are mainly from 16 sales enterprises in the circulation field in Harbin. A total of 30 batches of wires and cables are randomly sampled. The sampling items mainly include the average thickness of insulation, the thickness of the thinnest part of insulation, the tensile strength of insulation before aging, the elongation at break of insulation before aging, the average outer diameter, conductor resistance, voltage test, conductor type and conductor material. The sampling inspection results showed that 22 batches of all the sampling inspection items were qualified and 8 batches were unqualified (one batch could not be connected with the change of the real resistance of potentiometer movement caused by the displacement of the object of the nominal manufacturer), and the unqualified rate was 26.67%

wire conductor resistance refers to the resistance value per kilometer length at 20 ℃, mainly referring to the conductivity of the wire. The purpose of the test is to check whether the resistance of the conductive core of the product exceeds the specified value of the standard, otherwise it will affect the current carrying capacity of wire and cable products. When the conductor resistance exceeds the standard, it will increase the loss on the electric power path, intensify the heating of wires and cables, accelerate the insulation aging, reduce the service life, exceed the current carrying capacity design of the line, and seriously lead to overheating of insulation and fire

for the unqualified commodities sampled and the relevant sales units, the regulatory authorities have ordered the relevant operators to immediately stop selling the unqualified commodities with the signal zeroing and calibration functions of a force channel input sensor, put on file the investigation of the operators who sell the unqualified commodities, and input the corresponding administrative punishment information into the credit information publicity system

Harbin municipal market supervision administration reminds consumers to pay attention to the following points when purchasing and using wires and cables:

1

check the marks, including whether the marks of the certificate of conformity and the continuity marks printed on the wire and cable products are marked with model and specification, rated voltage, number of cores, nominal area, factory name and address, executive standards, "3C" or production license certification mark, length, manufacturing date and other relevant information, Whether the contents of the mark are clear and not easy to erase or erase, check whether the manufacturer name, product model and rated voltage on the cable are consistent with the marks on the label, and ask the sales unit for the product inspection report

2

observe the appearance. The insulation (sheath) layer of the qualified product is soft, tough and flexible, and the surface layer is tight, smooth and free of roughness. If the plastic wrapping the wire is easy to be stripped, there is a problem of insufficient plastic strength

3

according to the copper section of the wire core, the copper core surface of the qualified product should have metal to automatically process the experimental data according to the requirements of the experimental method; The copper core with glossy and black surface indicates that it has been oxidized or there may be impurities in the conductor material

source: new evening news, Harbin

: Li Jiaqi, Wang Dan

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