The Importance of Water Blocking Yarns in Cable Construction

Water blocking is a critical feature for many cable applications, especially those used in harsh environments. The purpose of water blocking is to prevent water from penetrating the cable and causing damage to the electrical conductors inside. One of the most effective ways to achieve water blocking is by using water blocking yarns in the cable construction.

Water blocking yarns are typically made of a hydrophilic material that swells when it comes into contact with water. This swelling creates a barrier that prevents water from penetrating the cable. The most commonly used materials are expandable polyethylene (EPE), polypropylene (PP), and sodium polyacrylate (SPA).
EPE is a low-density, high-molecular-weight polyethylene that has excellent water absorbency. When EPE fibers come into contact with water, they absorb the water and expand, creating a watertight seal around the conductors. This makes EPE an excellent material for water blocking yarns, as it provides a high level of protection against water ingress.
PP is another material that is often used for. PP fibers are hydrophobic, which means that they repel water. When used in a cable, PP fibers create a barrier that prevents water from penetrating the cable. PP fibers are typically used in combination with EPE fibers to provide an extra layer of protection against water ingress.
Sodium polyacrylate is a superabsorbent polymer that is often used. Sodium polyacrylate fibers have a high capacity to absorb water, which makes them an effective barrier against water ingress. The fibers absorb water and expand, creating a watertight seal around the conductors.
Water blocking yarns are typically incorporated into the cable during the manufacturing process. They are typically added as a layer around the electrical conductors, along with other components such as insulation and jacketing. The products are placed in strategic locations within the cable, such as at the cable ends or in areas that are prone to water ingress, to provide the maximum level of protection against water damage.
In conclusion, water blocking yarns are an essential component in cable construction for applications that require protection against water ingress. The use of water blocking yarns, made from materials such as EPE, PP, and sodium polyacrylate, can provide an effective barrier against water damage, ensuring the reliability and longevity of the cable.