Distribution Network Operators (DNOs) in various regions require medium voltage cables that combine high reliability, compliance with international standards, and resilience to demanding service environments. One recent project involved supplying Triplex 11 kV XLPE-insulated polymeric cables, manufactured to BS 7870-4.10 specifications, for urban and suburban distribution networks.
The customer’s primary goals were:
To ensure reliable primary distribution at 11 kV.
To minimize line losses and operational failures.
To meet DNO-specific technical specifications and safety regulations.
QZ Group designed and manufactured 11 kV Triplex Cables, tailored for the customer’s DNO project. The cables were optimized for installation in both underground ducts and direct burial conditions.
Conductor: Copper or Aluminium, class 2 stranded, sizes from 95 mm² to 300 mm².
Insulation: XLPE (Cross-Linked Polyethylene), rated at 90°C operating temperature.
Screen: Semi-conductive conductor screen + XLPE insulation screen.
Metallic Screen: Copper wires or tape providing fault current capacity.
Sheath: Black PVC or LSZH (Low Smoke Zero Halogen) upon request.
Formation: Supplied as Triplexed Cores for ease of installation.
Standards: Manufactured in full compliance with BS 7870-4.10 and IEC 60502-2.
Excellent electrical strength and dielectric performance.
High resistance to moisture ingress and UV exposure.
Long service life under continuous loading and thermal stress.
Triplex configuration reduces field installation time and improves system reliability.
Primary power distribution at 11 kV for DNOs.
Urban grid reinforcement projects in cities and towns.
Industrial park supply systems, ensuring stable medium voltage delivery.
Renewable energy integration, where 11 kV feeders connect wind and solar plants into DNO grids.
Challenge 1: Compliance with strict DNO standards – Every DNO has specific technical requirements.
Solution: QZ Group customized conductor sizes, sheath type (PVC/LSZH), and copper screen design to fully match DNO technical specifications.
Challenge 2: Reliability under high load – Increased demand caused cable overload risks.
Solution: XLPE insulation with 90°C continuous operation and 250°C short circuit withstand ensured safe long-term performance.
Challenge 3: Installation constraints – DNO contractors needed reduced on-site handling time.
Solution: Triplex formation simplified installation compared to three single cores, reducing both labor cost and project delays.
QZ Group carried out routine and type testing in accordance with BS and IEC standards, including:
Conductor resistance test
Partial discharge test
Voltage withstand test
Hot set test for XLPE insulation
Water penetration and UV resistance tests
Certificates of conformity and factory test reports were provided for each batch.
Cables were delivered on treated wooden drums, protected against moisture and mechanical damage.
Each drum carried project identification, cable type, and length for easy handling.
Shipment arranged in 40 ft containers to optimize freight costs for bulk order.
The project successfully energized several 11 kV feeders in urban and suburban networks, improving distribution efficiency and reliability. With QZ Group’s factory-direct sales model, the customer benefited from:
Competitive pricing compared to regional distributors.
Fast delivery within the project schedule.
Guaranteed compliance with BS 7870-4.10, ensuring approval by the DNO’s technical committee.
The application of Triplex 11 kV Cables under the BS 7870-4.10 standard demonstrates QZ Group’s capability to deliver medium voltage solutions for DNOs worldwide. By offering customized engineering, certified quality, and end-to-end logistics support, QZ Group has become a trusted partner in strengthening modern distribution networks.
