The fibers, 250um, are positioned in a loose tube made of a high modulus plastic. The tubes are filled with a water-resistant filling compound. A Fiber Reinforced Plastic (FRP) locates in the center of the core as a non-metallic strength member. The tubes (and fillers) are stranded around the strength member into a compact and circular core. After the cable core is filled with the filling compound to protect it from water ingress, the cable is completed with a PE sheath.