Construction of Cables

Construction of Cables



The conductor of cables is made of copper or aluminium. The conductors of 3.6/6kV cables, one single-core and multi-core cable are completely twisted with a stranded wire to reduce the cable outer diameter. The conductor can also be fabricated as a conductive core having a longitudinal water blocking function.


Conductor Shield

Cables with voltage 3.6/6kV and above are normally covered with a conductor shield. The conductor shield consists of a semi-conductive material that is extruded to eliminate the electric field concentration on the conductor surface and improve the working field strength of the cable.



Around the conductor, it is necessary to provide insulation to prevent electrical short circuits. Insulation is made from the extruded XLPE. Ultra-clean grade XLPE material is applied for above rated 35kv cables. The nominal insulation thickness is comply to corresponding standards.


Insulation shielding

The insulation shield is made of the extruded semi-conductive material which is covered each core insulation. The Insulation shields play roles in uniform magnetic field.  


Metal shield

The metal shield is made of copper tape or copper wire. It has the function of grounding shield, on-capacitance current and short-circuits current. Single-core and multi-core cables below 35kV are metal-shielded with wrapped copper tape. Special requirements for single-core cables of 35kV and below can also be shielded by copper wire.



The fillings is used in the finished multi-core cables that make the cable round. The metal shields on each core of the multi-core cable have reliable contact with each other, and there are phase separation marks under the metal shield of each core, and the entire cabled core has an appropriate band wrapping.


Metal sleeve

Cables above 35kV can be sheathed with lead, aluminum, copper or stainless steel, both as a grounding shield and as a waterproof seal.


Integrated waterproof layer

The longitudinally wrapped aluminum-plastic composite tape and the extruded outer sheath are radially waterproofed to form a comprehensive waterproof sheath instead of the metal sheath.


Metal armor

Multi-core cable armor consists of double-layer steel strip or galvanized round steel wire. For single-core cable used for AC, if it is required for armoring, use non-magnetic material or special steel wire armor if metal shield or metal is used. The jacketed cable shall be armored when required, and the sheath of PVC or PE shall be extruded as a cushion under armor.


Outer sheath

The outer sheath of the cable consists of PVC or PE. The outer sheath is generally black except for special requirements. The surface of the cable above 35kV has a conductive coating to enable voltage testing of the outer sheath.