Conductor Material: The conductor of THHN/THWN copper cable is made of high-purity multi-strand electrolytic copper with a purity of more than 99.95%. High-purity copper ensures good conductivity, with a conductivity close to 100% IACS (International Annealed Copper Standard), which can effectively reduce energy loss during current transmission and improve power utilization efficiency. The multi-strand stranded structure is a major feature, which is composed of multiple fine copper wires with a diameter of about 0.5mm twisted together. This structure not only enhances the flexibility of the cable, making it easier to bend during wiring and adapt to complex installation environments but also improves the fatigue resistance and mechanical strength of the cable. In environments with frequent vibration or bending, such as wiring in ships and rail transit, the multi-strand stranded structure can effectively disperse stress, making the cable not easy to break and prolonging its service life. At the same time, copper has good thermal conductivity, which can timely dissipate the heat generated by the cable during operation, avoiding the impact on cable performance due to excessive temperature.

Insulation layer material: The insulation layer is made of polyvinyl chloride (PVC) or cross-linked polyethylene (XLPE) materials. Among them, the insulation layer of THHN cable is a thermosetting polymer, which has High Heat Resistance and mechanical strength and can maintain stable performance at a long-term operating temperature of 90°C. The specially treated thermosetting polymer has a three-dimensional network structure, which gives it good anti-aging performance and a long service life. THWN type adds moisture-resistant design on the basis of THHN. Its insulation layer material is added with special moisture-proof agents, which can effectively prevent the invasion of moisture and is more suitable for humid environments. This insulating material not only has excellent insulation performance with a volume resistivity greater than 1×10¹⁴Ω·cm, which can effectively block current and prevent electric leakage accidents, but also has certain chemical corrosion resistance, can resist the erosion of common chemical substances such as acids, alkalis, and salts, and can be used in chemical workshops, laboratories, and other environments with chemical pollution. In addition, the insulating material also has good weather resistance, and is not easy to age and crack under natural environments such as sunlight and wind and rain erosion, and can maintain good performance for a long time.

Style design: The cable is cylindrical in overall shape, with a smooth and flat surface, without defects such as burrs, bubbles, or scratches. This not only ensures the appearance quality of the cable but also reduces resistance during wiring, facilitating pipe threading and laying. In terms of color, common colors include black, red, blue, etc. Cables of different colors can be used to distinguish different phases or uses, which is convenient for construction personnel to identify and wire, reducing the probability of wiring errors. The length of the cable can be customized according to customer needs, with common specifications such as 100 meters, 200 meters, and 500 meters, which can meet the wiring length requirements of different projects. Each coil of cable is neatly wound on a sturdy plastic or wooden reel, with baffles on both sides of the reel to prevent the cable from slipping during storage and transportation. The reel is printed with clear product identification, including model, specification, rated voltage, length, production date, manufacturer information, etc., which is convenient for users to identify and trace the product.

Copper rod preparation: First, high-purity electrolytic copper ingots are put into a melting furnace for smelting, with the temperature controlled at 1100-1200°C. During the smelting process, appropriate deoxidizers are added to remove oxygen and other impurities in the copper water, obtaining copper water that meets the purity requirements. The copper water is cast into copper rods with a diameter of about 8mm through a continuous casting machine. During the casting process, the casting speed and cooling intensity must be strictly controlled to ensure that the structure of the copper rod is uniform and dense, without defects such as pores and cracks.

Copper wire drawing and annealing: The copper rod is sent to a wire drawing machine for drawing, and through a series of dies of different sizes, the copper rod is gradually drawn into fine copper wires with a diameter of 0.5mm. During the drawing process, the drawing speed and mold lubrication must be controlled to ensure that the diameter of the copper wire is uniform and the surface is smooth. The drawn copper wire needs to be annealed. The copper wire is put into an annealing furnace, heated to 350-400°C under the protection of inert gas, and kept warm for a period of time to eliminate internal stress in the copper wire, improve its flexibility and conductivity, and make it a soft copper wire that meets the requirements.

Copper wire stranding: According to the requirements of different specifications, a number of 0.5mm soft copper wires are stranded on a stranding machine. When stranding, an appropriate stranding pitch must be set. The stranding pitches of 500, 600, and 700 Kcmil are 18mm, 20mm, and 22mm respectively. An appropriate stranding pitch can ensure the roundness and flexibility of the conductor. During the stranding process, it is necessary to ensure that the copper wires are arranged neatly, without crossing, overlapping, loose strands, etc., to ensure the conductivity and mechanical strength of the conductor. After stranding, the conductor is inspected for appearance and measured for size to ensure it meets the requirements.

Insulation layer extrusion: The Stranded Conductor is sent to the extruder, and at the same time, PVC or XLPE granules are added to the hopper of the extruder. For THHN cables, XLPE material is used, which is heated and melted in the extruder, with the temperature controlled at 180-200°C. The molten material is pushed to the mold through the rotation of the screw, and evenly coated on the surface of the conductor to form an insulation layer of a certain thickness. The insulation layer thickness of 500 Kcmil is 1.6mm, 600 Kcmil is 1.8mm, and 700 Kcmil is 2.0mm. For THWN cables, moisture-proof agents are added to the XLPE material. The extrusion temperature and process are similar to those of THHN type, but the addition ratio of moisture-proof agents must be strictly controlled to ensure its moisture resistance. During the extrusion process, the extrusion temperature, speed, and pressure must be strictly controlled to ensure that the insulation layer has a uniform thickness, is closely combined with the conductor, and has no defects such as bubbles, pinholes, or eccentricity.

Cooling and solidification: The cable after extruding the insulation layer immediately enters the cooling water tank for cooling, with the cooling water temperature controlled at 20-30°C. Through the rapid cooling effect of cold water, the insulation layer is solidified and formed to ensure its dimensional stability and mechanical properties. The cooling time is adjusted according to the specifications of the cable and the extrusion speed, generally 3-5 minutes, to ensure that the insulation layer is completely solidified.

Spark detection: The cooled cable must pass through a spark tester for insulation performance detection. The tester applies a high voltage of 3000V to the surface of the cable. If there are defects such as pinholes or cracks in the insulation layer, spark discharge will occur, and the equipment will automatically alarm and mark, so that unqualified products can be removed in time to ensure that the insulation performance of the cable meets the standard.

Printing identification: Product information is printed on the surface of the cable through a printing machine, including model, specification, rated voltage, temperature resistance level, execution standard, manufacturer name, production date, etc. The printing uses wear-resistant ink to ensure that the printing is clear and firm, not easy to fall off, facilitating product identification and traceability.

Take-up and packaging: Qualified cables are sent to the take-up machine and wound on plastic or wooden reels according to the set length (such as 100 meters, 200 meters, 500 meters, etc.). During the take-up process, the tension must be controlled to ensure that the cables are wound neatly and tightly without looseness or knotting. After winding, the cables are packaged, and the reels are wrapped tightly with plastic film to prevent dust and moisture from entering and protect the cables from damage.

Finished product inspection: Sampling inspection is carried out on the packaged finished cables. The inspection items include conductor resistance, insulation resistance, voltage withstand strength, outer diameter size, printing clarity, etc. Only products that fully meet the standards can leave the factory to ensure high-quality cable products for customers.

Quality guarantee: The product has a warranty period of 10 years. During the warranty period, if there is a quality problem with the product itself (such as insulation layer aging and cracking, conductor breakage, failure to meet insulation performance standards, etc., which are not caused by human factors), the company will provide free repair or replacement services. Customers need to provide purchase certificates and photos or videos of the faulty parts. After verification by the company's technical personnel, a solution will be given within 7 working days.

Technical support: If customers encounter any technical problems during the installation, laying, or use of the cables, they can call the company's after - sales service hotline at any time, or consult through online customer service, email, etc. The company's technical team is composed of experienced engineers who will provide professional answers and guidance within 24 hours, such as providing installation plan suggestions, solving technical problems during laying, and analyzing the causes of faults.

On - site service: For large engineering projects or complex fault situations, the company can arrange technical personnel to provide on - site services. Technical personnel will inspect the installation quality of the cables, guide construction personnel in correct laying and connection methods, assist customers in troubleshooting and maintenance, and ensure the normal operation of the electrical system. The cost of on - site service is determined according to the service content and distance, and a detailed quotation will be provided to customers in advance for confirmation.

Complaint handling: If customers have complaints about product quality, delivery delay, or service attitude, they can feedback through the company's after - sales complaint channels. The company will record and sort out the complaints, and assign special personnel to follow up and handle them. For general complaints, a reply will be given within 24 hours; for more complex complaints, the handling progress will be reported to customers regularly, and a final solution will be proposed within 10 working days to ensure customer satisfaction.

Return and exchange policy: If the received products have problems such as inconsistent specifications, damaged packaging, or quality defects, customers can apply for return or exchange within 15 days of receiving the goods. The company will verify the situation, and after confirmation, arrange for the return or exchange of the goods in a timely manner, and bear the relevant transportation costs. For customized products, return or exchange is only allowed if there is a quality problem caused by the company.

Regular follow - up: After the product is sold, the company will conduct regular follow - up visits to customers through telephone, email, or on - site inspections to understand the use of the product and collect customer opinions and suggestions. This helps the company continuously improve product quality and service levels and establish long - term and stable cooperative relations with customers.