Published: 2025-08-04 13:34:23
Selection of Cable Outer Sheath
The cable outer sheath, as the outermost protective structure of the cable, is in direct contact with the external environment. Its performance is crucial to the cable's service life and safe operation. Choosing the appropriate sheath material requires consideration of various factors such as the usage environment, mechanical performance requirements, and electrical performance requirements. The following analyzes the characteristics and applicable scenarios of common sheath materials for you:
PVC (Polyvinyl Chloride)
Performance characteristics: Low cost, mature processing technology. It has certain wear resistance and acid and alkali corrosion resistance, and good insulation performance. However, it has poor high-temperature resistance, with a long-term use temperature generally between -15℃ and 60℃. It easily hardens and cracks in low-temperature environments, and releases toxic gases when burned.
Applicable scenarios: Suitable for dry, room-temperature environments without strong chemical corrosion, such as fixed laying of cables inside residential buildings and power cords of ordinary electrical appliances.
PE (Polyethylene)
Performance characteristics: divided into low-density polyethylene (LDPE) and high-density polyethylene (HDPE). LDPE has good flexibility and outstanding low-temperature resistance, operating normally at around -40°C; HDPE has higher mechanical strength, stronger wear and impact resistance, but slightly less flexible. Both have good chemical corrosion resistance and insulation, and are more environmentally friendly than PVC, releasing no toxic gases during combustion.
Applicable scenarios: LDPE is suitable for occasions that require a certain degree of flexibility, such as cables in low-temperature environments; HDPE is suitable for fixed laid cables that require higher mechanical strength, such as underground direct-buried cables and cables laid inside pipes.
PUR (Polyurethane)
Performance features: Excellent wear resistance, one of the best among all common outer sheath materials, capable of withstanding frequent friction, scratches, and impacts. Excellent flexibility and good bending performance, maintaining good softness even in low-temperature environments. Strong oil resistance, hydrolysis resistance, chemical corrosion resistance, and certain weather resistance and UV resistance. However, the cost is relatively high, high-temperature resistance is average, and long-term usage temperatures are usually between -40°C and 80°C.
Applicable scenarios: Widely used in situations requiring frequent movement, bending, or wear, such as drag chain cables, robot cables, driving cables, underwater robot cables, etc., especially suitable for industrial automation, logistics warehousing, and underwater operations.
Rubber
Performance characteristics: Good elasticity, excellent flexibility, able to withstand frequent bending and twisting. Oil resistance and chemical corrosion resistance vary greatly depending on the type; for example, nitrile rubber has strong oil resistance, while neoprene rubber has good weather and chemical resistance. Ordinary rubber has average high-temperature resistance, with long-term use temperatures around 60°C, while silicone rubber and other specialty rubbers have excellent high-temperature resistance and can be used above 150°C.
Applicable scenarios: Nitrile rubber sheaths are suitable for oily environments, such as machine tool cables; Neoprene rubber sheaths are suitable for outdoor environments, such as agricultural machinery cables; Silicone rubber sheaths are suitable for high-temperature environments, such as cables for high-temperature equipment in metallurgy and chemical industries.
Fluoroplastics (such as PTFE, FEP, etc.)
Performance features: Excellent high-temperature resistance, long-term operating temperatures can reach above 200°C, and can even operate for short periods at higher temperatures. Extremely resistant to chemical corrosion, able to withstand almost all strong acids, strong alkalis, organic solvents, etc. It has excellent weather resistance, aging resistance, non-stick properties, and excellent insulation properties. However, it is costly, has poor flexibility, and is difficult to process.
Applicable scenarios: Mainly used in special environments with high temperature, strong corrosion, and high cleanliness, such as special cables in aerospace, chemical, and semiconductor fields.
Selection recommendations
Ambient temperature: For high-temperature environments, prioritize high-temperature resistant materials such as fluoroplastics and silicone rubber; For low-temperature environments, consider materials with good low-temperature resistance, such as PE and PUR.
Mechanical wear: In scenarios involving frequent movement and friction, such as drag chains, robots, and cranes, materials with strong wear resistance like PUR should be selected.
Chemical corrosion: In environments where acidic, alkaline, oily, and other chemical substances are present, select materials such as fluoroplastics, nitrile rubber, PE, etc., that are resistant to the corresponding chemicals according to the type of corrosion.
Laying method: For fixed laying in a mild environment, PVC and PE are the economical choice; for mobile laying, emphasis should be on flexibility and wear resistance, such as PUR and rubber.
Cost budget: For ordinary scenarios with low performance requirements, PVC or PE can be chosen to control costs; In special environments, performance should be prioritized, with materials like PUR and fluoroplastic selected.
In summary, the choice of cable outer sheath must strike a balance between performance, cost, and usage environment to ensure effective protection during long-term use, guaranteeing safe and stable operation.