Wires and cables are carriers for the transmission of electrical signals. During use, due to electrification or the environment, cables will withstand varying degrees of tension. Factors such as high temperatures and strong radiation can cause aging and affect the performance of cables. Therefore, the material requirements for wires and cables should be stricter to ensure product quality.
To give everyone a deeper understanding of the performance testing of wires and cables, the editor has compiled the following common questions and answers.
Q1: What are the categories of wires and cables?
Answer: Wires and cables typically refer to wire products used for transmitting electrical (magnetic) energy, and information, and realizing electromagnetic energy conversion. Considering the performance, structure, and usage characteristics of the products, all wire and cable products can be divided into five categories: bare wires, magnet wires, power cables, wires and cables for electrical equipment, and communication wires and cables. Bare wires can be divided into round wires, stranded wires, flexible connectors, and profiled wires; magnet wires can be divided by insulation layers into enameled wires, fiber-wrapped magnet wires, film-wrapped magnet wires, and inorganic insulated magnet wires; power cables can be divided by insulation type into oil-impregnated paper insulated power cables, plastic insulated power cables, and rubber insulated power cables; wires and cables for electrical equipment can be divided by product usage characteristics into general wires and cables, wires and cables for electrical equipment and instruments, and wires and cables for vehicles; communication wires and cables include local telephone cables, long-distance communication cables, and office cables.
Q2: What are the common test items for wires and cables?
Answer: With the development of science, technology, and consumer standards, various industries have increasingly high requirements for wire and cable products, making performance testing very urgent. According to the type of test items, they can be divided into mechanical properties, electrical properties, and combustion properties; mechanical properties include tests for tensile strength, elongation at break, hardness, etc.; electrical properties include tests for insulation resistance, conductivity, voltage resistance, etc.; combustion properties include tests for horizontal burning, vertical burning, glowing wire, etc. SGS suggests that customers choose relevant performance tests based on the actual application of the product when testing, such as outdoor cables that need to focus on aging tests and cables used for precision equipment that need to focus on voltage resistance, resistance, and other electrical properties.
Q3: How is the internal structure information of wires and cables measured?
Answer: Conventional wires and cables generally use vernier calipers and non-contact image measuring instruments to measure the cross-sectional information of wires and cables. The specific operation is to first select the target position, cut the cross-section, and then measure it in the size measuring equipment after the laboratory prepares the slice.
Q4: What is the tensile strength of wires and cables?
Answer: The tensile strength of wires and cables is the ability of the cable to resist material destruction under stress in the direction of the cable. It usually requires making a standard tensile sample and stretching it on a universal tensile machine. When the inner diameter of the insulation layer is small (generally the standard requirement is <5mm), a tubular sample is used; otherwise, a dumbbell-shaped sample is used. Different standards have different requirements for the material's stretching speed and sample shape.
Q5: How is the flame retardancy of wires and cables tested?
Answer: The general test method for wires and cables is to cut a certain length of wire and cable, fix it vertically or horizontally, and then use the required blowtorch at a certain angle to ignite the cable. The combustion performance of wires and cables is comprehensively evaluated based on whether the flame spreads, the burning speed, and whether there are burning droplets, and a combustion grade evaluation is given. Different standards have differences in cable length, flame height, burning angle, evaluation standards, etc.
Q6: What are the common testing standards for wires and cables?
Answer: The conductivity performance of wires and cables, such as the conductivity test standard, includes GB/T3954-2008, ASTM B193-02(2008), etc.; Contact resistance standards include EIA/ECA 364-06C-2006(R2012); Dielectric strength test standards include IEC 60243-1-2013, ASTM D149-09(2013); Combustion standards for wires and cables include UL 1581:2001 REV.6-2013 Section 1080 FV-2/VW-1, ASTM D2671-09, etc.; Mechanical performance tests for wires and cables, such as tensile strength, include JIS C3005:2014; Light aging simulation for wires and cables includes UL 2556-2015, etc. SGS suggests that enterprises can comprehensively choose the appropriate testing standards and items based on the application occasions, export countries, and performance characteristics of the product.
As a global leader in third-party testing and certification, SGS can provide testing services for electrical performance, mechanical performance, aging resistance, flame retardancy, etc., effectively improving product quality and helping enterprises stand out in the fierce market competition.
