The 50mm² copper electric cable, a customized power cable designed specifically for underwater environments, serves as a vital transmission device in marine engineering, underwater exploration, and water conservancy facilities. Leveraging the excellent conductivity of high-purity copper conductors and a specialized protective structure, it plays an irreplaceable role in underwater power transmission. Its customizable features allow precise adaptation to varying water depths, pressures, and water quality conditions, making it a core guarantee for underwater power supply.​ In terms of product performance, the cable’s key advantages lie in its dual protection of water resistance and mechanical strength. The conductor is made of electrolytic copper with a purity of over 99.9%, featuring a single-core cross-sectional area of 50mm² and a long-term current-carrying capacity of 180-220A, which can meet the high-power supply needs of underwater motors, detection instruments, and other equipment. The insulation layer uses cross-linked polyethylene (XLPE) or ethylene propylene rubber (EPR) with excellent water resistance. After special vulcanization treatment, it can maintain insulation stability for a long time in water depths ranging from 0 to 500 meters, preventing short-circuit faults caused by water penetration. The sheath layer is made of high-density polyethylene (HDPE) or polyurethane, which has properties such as water pressure resistance, seawater corrosion resistance, and UV aging resistance. Its tensile strength is not less than 20MPa, and its elongation at break exceeds 300%, enabling it to resist mechanical damage from underwater rock friction and marine biological attachment.​ The customized design is a prominent feature of this cable, with structural parameters adjustable according to specific needs. For example, for deep-sea operations, a steel wire armoring layer can be added with an armoring density of over 90%, allowing the cable to withstand water pressure above 10MPa; for low-corrosion environments such as freshwater lakes, the sheath material can be simplified to reduce costs. In addition, the cable length (from several meters to several kilometers), number of cores (1-6 cores), and end sealing methods (such as waterproof connectors, glue filling sealing) can also be customized to ensure perfect adaptation to underwater equipment. For instance, in submarine cable laying, a composite structure with optical fibers can be customized to achieve both power transmission and signal communication; in underwater robot power supply, a flexible structure can be designed to meet the needs of the equipment’s flexible movement.​ Its application fields cover multiple underwater scenarios: in marine engineering, it is used for power supply and equipment connection of offshore oil and gas platforms, withstanding seawater salt spray and temperature changes (-20℃ to 60℃); in the field of underwater exploration, it provides stable power for submersibles, sonar systems, etc., supporting deep-sea resource detection; in water conservancy projects, it is adapted to equipment such as gate hoists and underwater pump stations, coping with long-term immersion in freshwater or sediment environments; in municipal construction, it is used for power supply of lighting and drainage systems in cross-river tunnels, resisting river water pressure and water flow impact.​ In terms of price, affected by customized parameters and material costs, the price per meter usually ranges from 150 to 500 yuan. Steel wire armoring, special sealing processes, etc., can increase the cost by 30%-50%, while bulk customization (over 1000 meters) can enjoy a 10%-15% discount. Users need to comprehensively consider factors such as water depth and environmental corrosion to balance performance and cost. For example, short-term operations in shallow waters can choose economical solutions, while long-term deep-sea projects need to prioritize protection performance.​ In summary, the 50mm² copper electric cable for underwater use achieves safe and efficient underwater power transmission through material innovation and customized design. Its ability to dynamically adapt performance and price makes it a key supporting equipment for various underwater projects.