The cable sheath is the outer protection for the cable core or conductor. It is closely connected to the cable core and protects the cable interior against mechanical stresses, environmental influences in the form of moisture, UV light or corrosion and against destruction by chemical substances. It also provides contact protection to prevent people from coming into contact with the electrical conductor.
The cable sheath is made of a plastic with good insulation properties. It can be constructed as a layered sheath with strain relief or with rodent protection. If strain relief elements are integrated in the cable sheath, they can be made of fiberglass-reinforced plastic, Kevlar or metal. In a cable consisting of several individual cables, the outer protection is formed by the outer sheath.
Depending on the application, the cable sheath should have a high abrasion resistance, be flexible for laying, temperature resistant and resistant to chemical effects, flame retardant and also rodent- proof. For cables that are laid indoors, attention should be paid to their fire behavior when laid. Halogen-free materials are particularly suitable for this purpose, as insulating materials containing halogens release highly toxic gases in the event of fire.
Common materials used for cable sheaths are polyethylene( PE) and, as a halogen-free, flame retardant material, Flame Retardant Non Corrosive( FRNC). Polyethylene is used for outdoor cables and FRNC for indoor cables.