- Jun 25, 2020-
1. Electrical performance testing
Mainly there are conductor DC resistance, insulation resistance, finished product voltage test and insulated wire core voltage test, each of which is very important.
Conductor resistance mainly examines the material and cross-sectional area of the conductor. If the material of the conductor is not good or the cross-sectional area is seriously insufficient, the DC resistance of the conductor will be seriously exceeded.
Insulation resistance is to detect the resistance of the insulating material between two conductors. It should be large enough to provide insulation protection.
The voltage test of the finished product and the voltage test between the insulated wires not only require the cable to have sufficient insulation capacity, but also require the insulation or sheath material to be uniform and free of impurities, uniform in thickness, and free of invisible trachoma, pinholes, etc. on the surface.
2. Mechanical performance testing
It mainly examines the tensile strength and elongation at break of the insulation and sheath plastic materials, including before and after aging, as well as the bending test, bending test, load breaking test, insulation core tear test, Static bending test, etc.
Aging refers to the ability of insulation and sheath materials to maintain their original performance under high temperature conditions. If the tensile strength and elongation at break are unqualified, the sheath or insulator will easily break during the construction and installation of the cable, or the sheath and insulation of the cable used in the light or heat environment will easily become brittle and break.
In addition, since flexible cables are not fixedly laid, there are repeated pulling and bending during use. Therefore, the standard for flexible cables additionally stipulates that dynamic bending tests, bending tests, load breaking tests, and insulated cores should be added to the finished cables. Tearing test, static bending test, etc., to ensure that this cable meets the requirements in actual use.
3. Performance test of insulation and sheath materials
Including thermal weight loss, thermal shock, high temperature pressure, low temperature bending, low temperature stretching, low temperature impact, flame retardancy and so on.
The thermal weight loss test is to detect the degree of degradation and volatilization of the material after 7 days of high temperature aging at 80℃;
Thermal shock detection whether there is crack on the special winding insulation surface after a high temperature of 150℃ for 1h;
The high-temperature pressure detects the degree of retention of the elasticity of the insulating material after being cooled down after high temperature
All low-temperature tests generally refer to changes in mechanical properties at -15°C. They are used to detect whether the cable material becomes brittle, cracks, or breaks in a low temperature environment.
The flame retardant performance of the cable is to ignite the finished cable installed according to the standard with a special flame for a certain period of time. After the flame extinguishes by itself, check the burning of the cable. Of course, the less burnt part, the better, indicating that it is burning. Poor performance, better flame retardancy, and safer.
4. Logo inspection
The standard requires that the cable package should be accompanied by a label or logo indicating the product model, specification, standard number, factory name and place of origin. The specifications include rated voltage, number of cores and nominal conductor cross-section, etc.;
The surface of the cable should be printed with continuous signs of the manufacturer's name, product model and rated voltage. The spacing of the signs should be ≤200mm (insulation surface) or ≤500mm (sheath surface).
The content of the mark should be complete, clear and scratch-resistant. This requirement is to facilitate users to understand the type, specification and voltage level of the cable to prevent laying errors.
In addition, the color of the wire insulation core should be the color recommended by the standard.
5. Structure size detection
Including the thickness, thinnest thickness, overall dimensions of the insulation and sheath.
The thickness of the insulation and sheath plays an important role in the strength of the cable and its mechanical properties. Therefore, for cables of different specifications, the standards have strict regulations on the thickness, and the requirements must not be lower than that of the country. Standard value.
If the insulation thickness of the cable is too thin, it will seriously affect the safety of the cable. It will bring potential safety hazards such as cable breakdown, exposed conductors and leakage. Of course, the thicker the better, it should not affect the installation. Therefore, the standard sets a requirement for external dimensions. Limit this.