Solar photovoltaic (PV) plants in hot climates—such as deserts or tropical regions—experience extreme ambient and operating temperatures that stress DC cables. Cables exposed on rooftops or ground mounts can reach surface temperatures exceeding 80-90°C, impacting current-carrying capacity, insulation life, and system efficiency. In 2025, with massive solar deployments in sun-rich areas, understanding how solar cables perform under high temperatures is essential for reliable, long-term energy production and safety.

1. Introduction

Modern solar cables (e.g., H1Z2Z2-K type) are designed for harsh outdoor conditions, including intense heat. They connect modules, strings, and inverters, carrying DC currents in environments where ambient temperatures routinely exceed 40-50°C. Proper thermal management prevents overheating, voltage drop, and premature aging, ensuring 25-30+ year lifespans.

2. Challenges of High Temperatures in PV Plants

• Reduced ampacity: Heat lowers conductor current capacity.
• Insulation degradation: Prolonged high temperatures accelerate aging.
• Increased resistance: Higher losses and voltage drop.
• Thermal expansion: Risk of mechanical stress on connectors/terminations.
• Black cable surfaces absorb more heat, raising internal temperatures.

3. Temperature Ratings of Solar Cables

Standard PV cables are rated for:

• Continuous operation: 90°C conductor temperature.
• Short-circuit: 250°C for 5 seconds.
• Ambient range: -40°C to +90°C (some up to +120°C overload).

Actual cable temperature = ambient + solar irradiance rise (up to 60°C additional on black surfaces).

4. Cable Derating in Hot Climates

Derating factors adjust ampacity for temperatures above 40-60°C reference. EN 50618 and IEC guidelines provide correction tables.

5. Material Selection for Heat Resistance

Cross-linked polyolefin (XLPE or electron-beam irradiated) insulation and halogen-free sheaths dominate. Tinned copper conductors resist oxidation. Advanced compounds now offer 120°C ratings for extreme desert installations (e.g., Middle East, Australia).

6. Installation Best Practices in High Heat

• Use larger cross-sections (e.g., upsize 6 mm² to 10 mm²) to compensate derating.
• Route cables with airflow; avoid bundling or enclosed trays.
• Employ light-colored ties/clips to reduce heat absorption.
• Allow expansion loops at bends and terminations.
• Elevate cables off hot rooftops with spacers.
• Monitor with thermal imaging during commissioning.

7. Relevant Standards in 2025

EN 50618 (H1Z2Z2-K) specifies 90°C operation with thermal endurance tests. IEC 62930 and UL 4703 align globally. Ongoing updates address higher temperatures in utility-scale plants, with some manufacturers offering extended 120°C certified options.

8. Final Thoughts

High temperatures significantly impact solar cable performance in PV plants, but proper design—through derating, material choice, and installation—ensures reliable operation even in the hottest climates. As solar expands into desert megaprojects in 2025, heat-resistant cables are key to maximizing yield and minimizing losses over decades. Plan for heat from day one—your system's longevity depends on it.

For high-temperature-rated solar cables compliant with EN 50618 and beyond, contact Henan Province Jianyun Cable Co., Ltd. for expert solutions and quotes.