The main function of cable outer sheath is to enhance insulation performance and protect the cable from mechanical damage.

The standard for cable outer sheath is to calculate and control the thickness of the sheath according to the standard. The calculation formula is D (pre extrusion outer diameter) x 0.035+1. The thinnest point of the single core sheath is the nominal value x 85% -0.1; Thinnest point of multi-core sheath: nominal value x 80% -0.2%.

The cable sheath is the outermost layer of the cable, such as PVC insulation for VV and PVC sheath. The pipes worn outside are called protective pipes.

High density polyethylene. Compared with MDPE (medium density polyethylene) and LD/LLD (low density/linear low density), HDPE materials have a regular molecular chain structure, fewer branched chains, shorter branched chains, orderly arrangement of molecular chains, smaller distance between molecular chains, and greater intermolecular forces.