What design features enable longitudinal and lateral water resistance in medium-voltage power cables, and how do these mechanisms prevent moisture-induced failures?

Water-resistant medium-voltage cables integrate multi-layered protection systems to combat both lateral penetration and longitudinal moisture spread. For lateral resistance, an aluminum/polyester composite tape—bonded directly beneath the outer sheath—forms an impermeable barrier that blocks water ingress at puncture sites or damaged sections. Longitudinal protection relies on swellable technologies: water-blocking tapes, powders, or yarns placed between conductor strands and around metallic screens expand upon contact with moisture, creating gel-like seals that halt capillary action along the cable length.   Class 2 stranded conductors specifically incorporate swellable materials in interstrand gaps, preventing water migration from termination points into critical insulation layers. These features are integral to designs like N2XS(F)2Y and NA2XS(F)2Y cables, which maintain dielectric integrity in submerged or high-humidity environments. By combining physical barriers with reactive swelling mechanisms, these cables address the dual challenges of localized damage and widespread moisture propagation, ensuring reliable performance in underground, marine, and flood-prone installations.