Views:3 Author:Site Editor Publish Time: 2021-12-03 Origin:Site
1. Judge where the wires are good from the packaging
Whether it is wire or cable packaging, roller-type packaging is used. This type of packaging can reduce the abrasion of the insulation layer during delivery, transportation and handling, and is convenient for handling and installation. There is a certificate of conformity on the packaging, and the certificate should have complete information such as specifications and models, implementation standards, rated voltage, product meters, production date, factory name and address.
2. Judge where the wire is good from the material
Looking at the insulating layer rubber, the inferior insulating layer looks thicker, but it has no elasticity and is easy to tear off. It is actually made of recycled plastic. As long as it is squeezed slightly, it will become white and will drop powder.
3. Judge where the wires are good from the weight
The weight of each type of wire has a certain range, and a good quality wire must be within the weight range of its type. For example, the commonly used plastic insulated single-strand copper core wire with a cross-sectional area of 1.5mm2 has a weight of 1.8～1.9kg per 100m.
4. Judge where the wires are good from the color of copper
The color of copper used in good quality copper core wires and cables should be purple-red, shiny, and soft to the touch. The color of low-quality copper is purple-black, white, yellow, and hard.
5. Judge where the wires are good from the cross section
You must look at the cross section of the wire and cable. The production of each wire and cable has a national standard. Within the specified standard range, the error of the wire length cannot exceed 2%, and the cross-sectional wire diameter cannot exceed 0.02%, but it exists in the market. There are a lot of shortcomings in length, and falsification on the cross section (for example, the line marked with a cross section of 70 square millimeters is only 65 square millimeters thick in fact).
6. Judge where the wires are good from the eccentricity
Choose a piece of wire and cable to see if the core is in the middle of the insulation. If it is not in the middle, it is due to the eccentricity caused by the technician's technical problems. In the case of low power during use, there will be no problems. Once the power consumption is large, the current will break down the thinner side of the insulating layer.