Key Selection Criteria for MV Power Cables in Industrial Infrastructure Projects

Medium Voltage (MV) power cables (6kV–35kV) are the critical backbone of power distribution in industrial infrastructure, including manufacturing plants, mining sites, petrochemical facilities, data centers, and renewable energy stations. For engineers and project contractors, selecting MV power cables that meet technical specifications, operational reliability, and compliance requirements is pivotal to avoiding project delays, equipment failures, and safety risks.

For engineering and construction professionals, the primary prerequisite for MV cable selection is strict matching between the cable’s nominal voltage (Uo/U) and the industrial power system’s rated voltage. Per IEC 60502 and GB/T 12706 standards, the cable’s Uo (phase-to-ground voltage) and U (phase-to-phase voltage) must fully cover the system’s maximum operating voltage and transient overvoltages. For instance, a 10kV solidly grounded system requires an 8.7/10kV MV cable, not a 6/10kV cable—under-sizing the voltage rating will lead to insulation aging acceleration and potential breakdown under peak load conditions.

Additionally, the insulation level must be determined based on the system’s grounding mode: normal insulation is applicable to standard solidly grounded grids, while graded insulation (defense insulation) is mandatory for high-impedance or resonant grounding systems (common in mines, offshore platforms, and critical industrial plants) to enhance fault tolerance.

The conductor’s material and structure directly determine the MV cable’s current-carrying capacity, short-circuit thermal stability, and installation adaptability—key considerations for engineers during project design and material selection.

Copper (Cu) Conductors: With a conductivity of 102% IACS, copper conductors offer superior thermal stability (short-circuit temperature up to 250°C), corrosion resistance, and low voltage drop. They are recommended for critical load scenarios, including data centers, petrochemical plants, and fire-critical circuits, where operational reliability and minimal downtime are non-negotiable. While copper has a higher upfront cost, its long service life (40–50 years) and low maintenance requirements reduce the total cost of ownership (TCO) for industrial projects.

Aluminum (Al/AAAC) Conductors: Aluminum is 30–40% more cost-effective than copper and 35% lighter, making it suitable for long-distance cable runs, overhead duct installations, and non-corrosive industrial areas. Engineers must note that aluminum conductors require a 1.5–2 times larger cross-section than copper to achieve equivalent ampacity, and they are not recommended for high-short-circuit current environments or corrosive sites due to lower thermal stability.

Per GB 50217-2018 (Code for Design of Power Cable Engineering), the minimum cross-section of MV cable conductors for 10kV systems is 25mm². Stranded conductors (Class 2/5) are preferred for industrial applications due to their flexibility, which facilitates installation in tight spaces, vertical shafts, and areas with mechanical vibration—solid conductors are only used for small-size, low-vibration scenarios.

Insulation is the core barrier against electrical breakdown, and its selection must align with the project’s operating environment and technical requirements—engineers must prioritize insulation materials that balance durability, heat resistance, and cost-effectiveness.

XLPE (Cross-Linked Polyethylene) Insulation: As the most widely used insulation material for industrial MV cables, XLPE offers a continuous operating temperature of 90°C (MV-90) to 105°C (MV-105), high dielectric strength (≥25 kV/mm), and low dielectric loss. Peroxide-crosslinked XLPE, in particular, minimizes water treeing (a major cause of insulation failure) and is suitable for direct burial, indoor/outdoor installations, and general industrial scenarios. Its long service life and low maintenance make it the first choice for most industrial MV cable projects.

EPR (Ethylene Propylene Rubber) Insulation: EPR insulation excels in harsh industrial environments, with an operating temperature range of -55°C to +105°C, superior flexibility, and moisture resistance. It is ideal for mining sites, offshore facilities, and high-vibration areas (e.g., manufacturing plants with heavy machinery), where XLPE may become brittle or degrade over time. EPR-insulated cables also offer better resistance to chemical corrosion, making them suitable for petrochemical plants.

Industrial construction sites and operational environments pose multiple mechanical hazards, including physical impact, radial pressure, tensile stress, and environmental erosion. Engineers must specify MV cables with appropriate armoring and sheathing to ensure long-term reliability.

Armoring: Steel tape armor (STA, YJV22) provides effective protection against radial pressure, ground movement, and rodent damage, making it suitable for direct burial and underground industrial installations. Steel wire armor (SWA, YJV32) offers high tensile strength, designed for vertical shafts, bridges, and large-drop installations (e.g., mine shafts, offshore platforms) where cables are subject to significant tension. Non-magnetic armor (stainless steel/aluminum) is required for single-core MV cables to avoid eddy-current heating.

Sheathing: PVC sheaths are cost-effective and suitable for general industrial environments with no extreme moisture or chemical exposure. PE/HDPE sheaths offer excellent water and moisture resistance, ideal for direct burial, wet locations, and coastal industrial facilities. LSZH (Low Smoke Zero Halogen) sheaths are mandatory for fire-critical zones (e.g., data centers, tunnels, emergency power systems) as they emit minimal toxic fumes and smoke during combustion, complying with IEC 60332-3 and GB/T 19666 standards.

Engineers and project contractors must verify that MV cables meet the following electrical performance criteria to ensure system safety and stability:

Ampacity: The cable’s current-carrying capacity must exceed the maximum continuous load current, including allowances for load diversity and future expansion. Derating factors (ambient temperature, group installation, soil thermal resistivity) must be considered per IEC 60364 and GB 50217.

Short-Circuit Withstand: MV cables must withstand the system’s maximum short-circuit current (Isc) for 1–3 seconds without thermal damage. 

Voltage Drop: Limited to ≤3–5% from source to load (per IEC/GB standards) to ensure stable operation of voltage-sensitive equipment (VSDs, PLCs, precision machinery).

All MV cables must comply with international and regional standards, including IEC 60502 (MV power cables), GB/T 12706 (power cables for rated voltages 35kV and below), NEC 310 (US), and EN 50215 (Europe). Relevant certifications (CE, UL, CCC, KEMA) must be verified to guarantee product quality and project compliance.

Case 1: 45.33 Million Yuan New Energy Project

User: Guoneng (Dachaidan) Photovoltaic Power Generation Co., Ltd.

Project: 1 million kW wind-solar-storage project AC cable procurement

Key Requirements: Outdoor, long-distance, moisture resistance

JINHONG Solution:

Cable Model: ZRC-YJLHY23-26/35KV, ZC-YJY23-26/35KV

Core Advantages: PE sheath (waterproof), flame retardant (ZRC), suitable for Gobi outdoor environment

Project Outcome: On-time delivery in August 2024, stable operation for 6 months.

Case 2: 25.83 Million Yuan Medical Project

User: Shanghai Baoye Group Co., Ltd. (Mengcheng People's Hospital)

Project: Comprehensive hospital power distribution system

Key Requirements: Fire safety, reliability, low smoke

JINHONG Solution:

Cable Model: FS-WDZ-YJY23 26/35KV, NH-YJV22 26/35KV

Core Advantages: LSZH sheath (low smoke, zero halogen), NH flame retardant, meeting hospital fire standards

Project Outcome: Passed fire acceptance in May 2024, no power failure records.

Case 3: 26.91 Million Yuan Coal Power Project

User: Xinjiang Zhongneng Electric Power Development Co., Ltd.

Project: 2*1 million kW coal power project cable procurement

Key Requirements: High temperature, vibration resistance, vertical installation

JINHONG Solution:

Cable Model: ZC-YJV22-8.7/15KV-3*120, ZC-YJV62-26/35KV-1*50

Core Advantages: Steel wire armor (tension resistance), high-temperature XLPE insulation (adapting to boiler area 60°C environment)

Project Outcome: Delivered in January 2025, matching the coal power unit's commissioning schedule.

Combining the above cases and parameters, the following MV cable selections are recommended for engineering and construction professionals, covering common industrial scenarios:

• General Industrial Direct Burial: Cu/Al XLPE STA PVC (YJV22) — Balances mechanical protection and cost-effectiveness, suitable for standard industrial distribution.
• Fire-Critical Zones (Data Centers, Emergency Systems): Cu XLPE LSZH FR (WDZA-YJY) — Complies with fire safety standards, ensuring circuit integrity during fires.
• Mines/Petrochemical Plants: Cu EPR Armored Cables (YJV32-EPR) — Resistant to vibration, chemical corrosion, and extreme temperatures, meeting ATEX/IECEx certification requirements.
• Vertical Shafts/Bridges: Cu XLPE SWA LSZH (YJV32) — High tensile strength and fire safety, suitable for high-tension installations.
• Long-Distance Distribution: Al XLPE STA PE (YJLV22) — Cost-effective, lightweight, suitable for large-scale industrial parks.

Conclusion

For engineers and project contractors, selecting MV power cables requires a systematic approach that integrates voltage compatibility, conductor/insulation performance, mechanical protection, electrical safety, and standard compliance. The added engineering cases and technical parameter table provide direct reference for project design, material selection, and on-site construction, helping professionals avoid common selection errors and ensure project safety and reliability.

JINHONG specializes in high-performance 6kV–35kV MV power cables, fully compliant with IEC, GB, and NEC standards. Our products are engineered for industrial harsh environments, with customizable options for copper/aluminum conductors, XLPE/EPR insulation, and specialized armoring/sheathing. For project-specific cable design, technical parameter verification, and on-site support, contact JINHONG’s engineering team to ensure optimal material selection and project success.