Engineers who design large infrastructure projects must account for the long-term impacts of metal corrosion. Structures like bridges, oil and gas pipelines, and water towers are particularly vulnerable to corrosion due to standing water or caustic substances.
To protect these structures, designers often employ a solution called Cathodic Protection to control the corrosion of metal surfaces. Cathodic Protection Cable (CPC) is a critical component of that solution.
Cathodic protection is described as “a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell.” It works by connecting the protected structure to a more easily corroded metal. When an electrical current passes between the two, the ‘sacrificial’ metal acts as an anode and corrodes, sparing the protected metal. For larger structures such as pipelines, a DC electrical current may be added to optimize the electrochemical process.
CPC, the specialized cable used to connect the two metal surfaces, is a stranded copper wire with highly protective insulation. CPC is designed to withstand the most extreme conditions and provide exceptional strength and durability.
Central to CPC’s performance is the high molecular weight polyethylene (HMWPE) insulation. HMWPE uses much thicker insulation than standard wire (110 mm versus 30-45 mm). It is a very dense form of polyethylene with the following characteristics:
Kris-Tech offers three kinds of CPC. The first is known simply as HMWPE, referring to the insulation encompassing the copper wire.
For even greater protection in more demanding conditions, Kris-Tech also manufactures Halar and Kynar CPC. Both use an additional fluoropolymer lining that sits between the copper wire and the HMWPE insulation: an ECTFE liner for Halar, and PVDF for Kynar.
Halar and Kynar are both excellent products. For extreme conditions, however, Kris-Tech recommends Halar as its fluoropolymer of choice.
Kris-Tech CPC cables meet all applicable industry standards, including UL, ASTM, NEMA, and ICEA, and all products are spark tested at 7500 VAC unless otherwise specified.
Cathodic protection is widely used to protect submerged or buried metal structures. Here are several industrial applications that employ cathodic protection cable:
Oil fields, pipelines, and refineries. Oil and gas production infrastructure is awash with standing water and caustic chemicals. Metal corrodes quickly in this wet, dirty environment, and producers use cathodic protection to extend the lifespan of pipeline and refinery assets.
Bridge structures. Bridge structures, whether buried or submerged, are highly susceptible to corrosion. Particularly vulnerable are bridges that have been exposed to salt from winter de-icing. CPC is extremely resistant to the chloride ions produced by de-icing, making the cable well-suited to cathodic protection solutions for bridges.
Water towers. While most people have seen rusty water towers, the worst corrosion can occur inside the water tank, eventually compromising structural integrity. CPC’s moisture-resistant and submersible properties make it a natural fit for deployment in water towers and tanks.
Marine buildings. Seawater is typically more corrosive than freshwater, as its chloride ions can quickly penetrate metal surfaces. Corrosion rates vary due to temperature and oxygen availability. With its extreme resistance to water and chemicals, CPC is ideal for marine construction projects (e.g., oil rigs, offshore wind farms, and harbor buildings) that require cathodic protection.
Storage tanks. Above ground storage tanks often contain highly caustic liquids, and their maintenance and safety are tightly regulated. These storage tanks often use cathodic protection (and cathodic protection cable) to slow corrosion and reduce ongoing maintenance expenses.
Ships and boat hulls. Ships are exposed to seawater, diesel fuel, corrosive gases, and solvents — conditions that call for CPC’s durability and performance.
Customers looking for cathodic protection cable can count on Kris-Tech to address all of their requirements. We offer several gauges of CPC, from 14 gauge (1.9mm) to 350 mm in diameter. Our CPC is available in 11 colors and can be ordered with customized print legends. As with all of our cable solutions, Kris-Tech also offers non-standard lengths, smaller minimum runs, and no cut or reel charges — all backed by the industry’s best lead times.