May 31, 2023
On July 23, official website of Chongqing Market Supervision Authority released quality control and spot inspection data for 10 products including LPG in 2019. In accordance with relevant provisions of "Product Quality Law of People's Republic of China" and other laws and regulations, 2019 student stationery, liquefied petroleum gas, clothing, bedding, wool fiber products, wires and cables, furniture, sockets, switches, fertilizers, etc. 10 kinds Product supervision and random inspection notice is as follows.
Including 50 batches of cable and wire products from 26 manufacturing enterprises in 12 districts and counties, including Jiulongpo District, Shapingba District, Nan'an District, Bishan District, Dadukou District, Jiangjin District, and Nan District, participated in this random inspection. District, as well as Kowloon 50 batches of products from 10 trading companies in Po District and Yubei District.
45 batches qualified in manufacturing area and 5 batches failed, with a pass rate of 90%. Non-qualified items include: conductor resistance, average insulation thickness, thickness of thinnest part of insulation, average thickness of sheath, thickness of thinnest part of non-metallic sheath, rate of change in tensile strength before and after aging of insulation. , elongation at break before and after aging of insulation 11 items, including rate of change in elongation, thermal elongation of XLPE insulation, sheath tensile strength before aging, sheath tensile strength after aging, and maximum sheath elongation change rate after aging.
42 batches passed circulation standard and 8 batches failed test, with a pass rate of 84%. Non-qualified items include: conductor resistance, average insulation thickness, thickness of thinnest part of insulation, and average sheath thickness.
As main channel for transmission of electricity, wires and cables are laid in dark, but "responsibility" is heavy. When using low-quality and low-quality wires and cables, light ones can lead to a short circuit and electric shock, and heavy ones can lead to fires and human casualties. Only under condition of excellent quality of cable can safety of production and life be guaranteed. So how do you choose quality wire and cable?
How to tell good wires and cables from bad ones
1. Look at appearance, it's a relatively easy way to tell difference
See if there is a quality system certification and 3C certification;
Second, check if qualified certificate is standardized;
Thirdly, check if factory name, factory address, control stamp and production date are printed on cable product.
Fourthly, check if wires are printed with product information such as trademarks, specifications, and voltage.
2. Wires and cables should be checked for feel
It is recommended to manually bend wire head several times. Products that have soft hands, good resistance to fatigue, high elasticity of plastic or rubber, and no cracks in wire insulator are best suited. At same time, it also depends on whether surface of cable is smooth and whether color of copper is smooth in cross section. Generally, color of quality copper is brighter and softer.
3. Define Copper
As a general rule, copper strand of certified wire should be fuchsia, shiny and soft to touch. The copper strand of fake and low-quality wires is purplish-black, yellowish or white in color, with a lot of impurities, poor mechanical strength and poor toughness. When checking, simply peel off 50px of wires from one end, and then rub a piece of white paper on copper strand. If there is a black substance on white paper, then there is more impurities in copper strand.
Good quality wires are usually within specified weight range. Here are some datasets for reference. Under normal conditions, commonly used solid plastic insulated copper wire with a cross-sectional area of 1.5 mm2 has a weight of 1.8-1.9 kg per 100 m, and a solid plastic insulated copper wire is 2.5 mm. mm2 has a weight of 3-3.1 kg per 100 m, 4.0 mm2 solid copper wire with plastic insulation weighs 4.4-4.6 kg per 100 m.
5. Compare prices
Because production cost of counterfeit and low-quality wires is low, when selling wires and cables, dealers often sell them at low prices under guise of low prices and high quality in order to deceive people. Therefore, psychology of greed for cheapness must be abandoned.
Tips for buying a cable
Look carefully at printed sample label, inscription is illegible and address is unknown.
If you roll insulation shell by hand, color and characters will fade and quality will be poor.
Use your nails to draw and cut lines and lines will scratch and peel off.
Bend insulated wire several times and break it three or four times.
Ignite insulation of wire with fire and leave an open flame to ignite spontaneously.
The core of wire is usually made of aluminum and copper, color becomes dark and luster becomes light.
Carefully measure inner diameter and outer diameter and look at pine skin when weighing.
Finally, I would like to remind everyone. When buying wires and cables, you can’t be subconsciously sloppy, because if you sag a little, purchased products may be fraught with hidden dangers to quality of life in future.