BS 7870-4.10 Copper Unarmoured LSZH Single Core Cable

What is BS 7870-4.10 19/33kV Copper Single Core Unarmoured LSZH Cable?

The BS 7870-4.10 19/33kV Copper Single Core Unarmoured LSZH Cable is a medium-voltage power distribution cable manufactured in strict adherence to British Standard BS 7870 Part 4 Section 10 and international specification IEC 60502-2. Operating at a rated system voltage of 19/33 (36)kV, it provides primary electrical power transmission across regional utility distribution grids, primary step-down substations, industrial installations, and infrastructure projects requiring dependable performance and enhanced fire safety.

The cable features a Class 2 stranded copper conductor insulated with dry-cured Cross-Linked Polyethylene (XLPE) bounded by an extruded conductor screen and a fully bonded semi-conductive insulation screen. Over the paper separation tapes, an earth-fault metallic screen consisting of plain copper wires (with optional helical copper equalising tape) is applied, enclosed within an extruded, UV-resistant black Low Smoke Zero Halogen (LSZH) outer jacket. Unarmoured for lightweight flexibility and easy handling in single-way ducting or direct underground trenches, the cable limits toxic fumes, corrosive gases, and opaque smoke under fire conditions per IEC/EN 60754 and IEC/EN 61034 standards.

BS 7870-4.10 19/33kV Copper Single Core Unarmoured LSZH Cable Construction

• Conductor: Class 2 Stranded Annealed Copper conductor.
• Conductor Screen: Semi-conductive Cross-Linked Polyethylene (XLPE) extruded compound.
• Insulation: High-grade Cross-Linked Polyethylene (XLPE) compound providing dielectric strength up to +90°C continuous operating temperature.
• Insulation Screen: Semi-conductive Cross-Linked Polyethylene (XLPE) extruded compound (Fully bonded type).
• Separation Layer: Paper separation tapes applied over the insulation screen.
• Metallic Screen: Plain copper wires, with number and diameter configured to meet specified earth fault ratings, plus optional helically applied copper equalising tapes.
• Outer Sheath: UV-resistant, flame-retardant Low Smoke Zero Halogen (LSZH) compound.
• Sheath Colour: Black.

Applications

BS 7870-4.10 single-core unarmoured copper LSZH medium-voltage cables are engineered for primary electrical energy transmission across public utility and industrial environments:

• Utility Power Distribution Networks: Primary 33kV distribution circuits routing electrical power from generation sources to regional substations and switching stations.
• Substation Power Supply Stations: Interconnecting primary step-down transformers, switchgear lineups, and distribution bus sections.
• Direct Burial in Ground: Subterranean installations laid directly in prepared soil trenches.
• Single-Way Ducting & Underground Pipes: Pulled through subterranean conduit pipes and duct runs with reduced pulling tension.
• Enclosed & Life-Safety Infrastructure: Utility tunnels, transit substations, and industrial manufacturing plants requiring LSZH fire protection against toxic fumes and corrosive gases.

Specifications & Dimensions

Huadong Cable Group manufactures BS 7870-4.10 Copper Single Core Unarmoured LSZH 19/33 (36)kV cables across cross-sectional areas from 70mm² up to 1000mm² (70, 95, 120, 150, 185, 240, 300, 400, 500, 630, 800, and 1000mm²) in strict adherence to BS 7870-4.10 and IEC 60502-2. Conductor diameters range from 9.8mm to 38.0mm, diameter over insulation spans from 27.0mm to 57.3mm, and overall outer diameters range from 34.1mm to 71.0mm, with nominal unit weights between 1,560 kg/km and 12,200 kg/km and maximum permissible pulling tensions from 350 kg up to 5,000 kg. Operating reliably at a continuous conductor operating temperature of +90°C and a short-circuit thermal limit of +250°C, maximum copper conductor DC resistance at 20°C ranges from 0.2680 Ω/km (70mm²) down to 0.0176 Ω/km (1000mm²). In trefoil configuration, continuous current carrying capacity reaches up to 1,430A in air (25°C), 1,010A buried (15°C), and 920A in single-way ducts for 1000mm² cables, with conductor 1-second short-circuit current withstand up to 143.8 kA, a 35mm² copper screen short-circuit rating of 4.8 kA, and a 50mm² copper screen rating of 8.2 kA. Standard minimum installation bending radius is 20 times the overall cable diameter in full alignment with British Standards.

Standards

Design & Material Standards: BS 7870-4.10, IEC 60502-2
Low Smoke Zero Halogen Performance: Low Smoke Halogen Free according to IEC/EN 60754-1/2, IEC/EN 61034-1/2
Flame Retardancy & Environmental: Flame Retardant according to IEC/EN 60332-1-2; UV Resistant
Voltage & Electrical Ratings: Voltage Rating Uo/U (Um): 19/33 (36)kV
Thermal Ratings: Conductor maximum operating temperature: +90°C; Maximum short-circuit temperature: +250°C
Bending Radius: Minimum Bending Radius: 20 × overall diameter
Regulatory Compliance: RoHS Directive 2015/65/EU, REACH Regulation EC 1907/2006, CE Marked

Frequently Asked Questions

Q: What is the technical function of the fully bonded semi-conductive insulation screen?
A: The fully bonded semi-conductive screen provides a seamless, void-free molecular interface with the XLPE insulation, preventing partial discharge activity and maintaining a uniform radial electric field under 33kV high-voltage stresses.

Q: Why is an unarmoured single-core configuration chosen over an armoured design?
A: Unarmoured single-core cables eliminate metallic armour losses and circulating currents, significantly reduce overall cable weight and diameter, and provide greater pulling flexibility for installation inside single-way ducts and utility conduits.

Q: Are waterblocking options available for BS 7870-4.10 cables?
A: Yes, optional conductor waterblocking and longitudinal waterblocking tape barriers are available upon specification to prevent moisture migration along the core.

Q: What commercial payment terms does Huadong Cable accept for international project orders?
A: We accept standard international commercial payment terms, primarily Telegraphic Transfer (T/T, with 30% advance deposit and 70% against shipping documents) and 100% Irrevocable Letter of Credit (L/C) at sight.

Copper Single Core Unarmoured LSZH Cable – Why Choose Huadong Cable?

Huadong Cable Group manufactures BS 7870-4.10 19/33kV Copper Single Core Unarmoured LSZH cables in strict compliance with British Standard BS 7870-4.10 and IEC 60502-2 specifications. Utilizing high-purity electrolytic copper rod, our advanced drawing and stranding equipment produces Class 2 stranded conductors that ensure tight dimensional tolerance, optimal compaction density, and minimum electrical DC resistance. On our triple-extrusion catenary continuous vulcanization (CCV) lines, the semi-conductive conductor screen, high-cleanliness XLPE insulation, and fully bonded insulation screen are applied simultaneously under pressurized dry nitrogen vulcanization, eliminating microscopic voids and keeping partial discharge levels well below standard limits.

Backed by more than 20 years of precision cable engineering expertise, Huadong Cable Group operates testing laboratories accredited under ISO/IEC 17025 and quality management systems certified to ISO 9001 and CE frameworks. Direct factory manufacturing eliminates middleman trading markups, allowing us to provide competitive factory pricing, 100% routine electrical and spark testing verified by certified Mill Test Certificates (MTC), continuous drum cuts packaged on heavy-duty ISPM 15 heat-treated export wooden reels, and dependable logistics for international electric utilities, infrastructure developers, and industrial EPC contractors worldwide.