What is a Solar Cable?

The Solar Energy Boom and the Critical Role of Cables

Against the backdrop of global advocacy for green energy and sustainable development, solar power has surged as a clean, renewable energy source. Data from the International Energy Agency shows that over the past decade, global solar photovoltaic (PV) installed capacity has grown at an annual rate exceeding 20%. By 2023, it accounted for 37.33% of total installed capacity, with over 250GW added that year—a figure continuing to rise annually—making it the fastest-growing renewable energy source.
Solar systems primarily consist of solar panels, inverters, mounting structures, cables, and junction boxes. Among these, solar cables (photovoltaic cables) connect solar panels, inverters, and batteries, transmitting electrical energy. They are critical for the proper functioning of solar systems and the efficient utilization of electricity.
Given the vital role of solar cables, this article provides a comprehensive guide to understanding them, covering definitions, construction, and more.

Solar Cables: The Dedicated Pathways of PV Systems

Solar cables, formally known as photovoltaic (PV) cables, are specialized cables designed for solar photovoltaic power generation systems. They transmit direct current (DC) between solar modules, inverters, and energy storage batteries, serving as the critical link for power transfer and utilization.
Compared to standard electrical cables, solar cables possess unique characteristics. Structurally, they employ dual-layer insulation, offering greater safety and durability than single-layer insulation in standard cables. Materials typically include cross-linked polyethylene or irradiated polyolefin, providing high-temperature resistance, UV resistance, aging resistance, and corrosion resistance. These cables maintain stable performance in harsh environments with a lifespan of up to 25 years or longer. In contrast, the polyvinyl chloride insulation used in standard cables exhibits inferior weather resistance and durability. In terms of protection, solar cables are waterproof, moisture-resistant, salt-fog resistant, UV-resistant, and flame-retardant, adapting to complex natural environments. Conventional cables are primarily suited for stable indoor conditions with insufficient protective capabilities. Additionally, solar cables commonly feature black and red colors for negative and positive connections respectively, facilitating installation, maintenance, and circuit identification. Conventional cables come in diverse colors without standardized coding rules.

Internal Structure of Solar Cables

The long-term stable power transmission of solar cables in harsh outdoor environments is attributed to their construction and materials.
Conductor: Typically tin-plated copper is used. Copper's high conductivity minimizes current transmission losses. However, copper is prone to oxidation and corrosion. Tin plating forms a dense oxide layer, enhancing oxidation resistance and corrosion protection to ensure stable system operation.
Insulation Layer: Primarily composed of cross-linked polymers such as cross-linked polyethylene (XLPE) and cross-linked polyolefin (XLPO). The cross-linking process enhances performance, providing high-temperature resistance and UV resistance. This ensures stable insulation properties under high temperatures and direct sunlight, extending the cable's service life.
Outer Sheath: Located at the outermost layer, it uses weather-resistant materials like rubber or polyvinyl chloride (PVC), supplemented with UV stabilizers and antioxidants. This layer provides UV resistance and weatherproofing, protecting the cable in harsh environments.
Single-core vs. Multi-core: Single-core cables feature a simple structure, lower cost, and better heat dissipation, but offer poor flexibility. Multi-core cables offer superior flexibility for complex installations and can transmit multiple signals or power simultaneously, but they are more expensive and require electromagnetic interference (EMI) shielding.
Double Insulation: Features both an inner insulation layer and an outer insulation sheath. The inner layer isolates conductors to prevent leakage, while the outer layer enhances mechanical strength and provides protection against water, UV radiation, and other elements, improving cable safety and reliability.

Iunveiling the Technical Characteristics of Solar Cables

Solar cables deliver long-term stable performance in demanding outdoor environments thanks to their exceptional technical properties, which determine cable performance, lifespan, and the safety and efficiency of solar systems.
Rated Voltage: A critical technical parameter, commonly specified as 600/1000V DC or 1500V DC. Small-scale distributed solar systems typically use 600/1000V DC cables, while large solar power plants often adopt 1500V DC cables to enhance transmission efficiency and reduce line losses. Increasing voltage from 1000V DC to 1500V DC reduces current by approximately 33% at the same power output, significantly lowering line losses.
Temperature Range: Operating temperatures typically span –40°C to +90°C, though specially designed cables and materials can withstand higher temperatures. Cold regions require freeze resistance, while hot climates demand insulation and sheathing materials that maintain stable performance at elevated temperatures—cables with cross-linked polyethylene insulation demonstrate excellent high-temperature stability.
Environmental Resistance: In outdoor settings, UV resistance, ozone resistance, and weather resistance are critical. UV radiation accelerates cable material aging; adding UV stabilizers to the sheath prevents degradation. Insulation and sheath materials exhibit good ozone resistance. Weather resistance ensures adaptability to diverse climatic conditions, guaranteeing reliable power transmission.
Flame Retardancy and Low Smoke Emission: In solar systems, flame retardancy and low smoke emission are critical. Flame-retardant materials prevent fire spread, while low smoke emission design minimizes smoke and harmful substances during combustion. With over 60% light transmission during burning, these cables ensure personnel safety during fires.

Diverse Types, Each with Unique Advantages

Within solar power generation systems, different types of solar cables serve distinct roles.
PV Single-Core Cable: Commonly used to connect solar panels and inverters, it efficiently transmits direct current. The single-core structure minimizes current loss and reduces costs.
Solar DC Cable: Used to connect photovoltaic modules, it features excellent weather resistance and reliably transmits direct current in complex outdoor environments.
Solar Extension Cable: Pre-installed with MC4 connectors at both ends for easy installation, it extends cable length and simplifies maintenance and replacement operations. 
Battery Cables / Solar Inverter Cables: Battery cables connect battery banks, solar panels, and inverters to enable energy storage and release; solar inverter cables link inverters to the grid or electrical appliances, transmitting alternating current (AC). These cables require high current-carrying capacity and excellent electrical performance.

Extensive Applications, Illuminating the Green Energy Landscape

​Solar cables deliver outstanding performance and reliable quality, playing a pivotal role across diverse solar applications to support green energy development. ​
Residential Rooftop Solar Systems: As environmental awareness grows, more households install rooftop solar panels. Solar cables transmit the direct current (DC) generated by these panels to inverters, which convert it into alternating current (AC) for household appliances. These cables require excellent conductivity and adaptability to complex rooftop environments to ensure system reliability and help families reduce energy consumption and emissions. ​
Commercial and Industrial Solar Facilities: Addressing substantial energy demands, solar cables connect extensive arrays of panels to inverters for large-scale power generation. Widely deployed in malls, office buildings, and factories, these cables must handle long-distance, high-current transmission with exceptional reliability. Their durability and low maintenance costs underpin corporate sustainability initiatives.
Solar Farms and Utility-Scale PV Projects: These large-scale solar initiatives rely on solar cables to transmit substantial electricity to inverters and substations. Demanding exceptional performance and strict safety compliance, these cables serve as critical engines for green energy transition.
Off-Grid Solar Systems and Battery Storage Units: These provide energy solutions for regions and users without grid access or requiring high electrical independence. Solar cables connect solar panels, batteries, and inverters, ensuring power supply in remote areas and specialized applications.
Hybrid Renewable Energy Systems: Combining the advantages of multiple energy sources, solar cables interconnect diverse energy components to achieve synergistic utilization. Acting as a bridge, they tightly integrate various energy types, supporting stable and sustainable energy supply.

Significant Advantages of Solar Cables

Within solar power generation systems, solar cables deliver exceptional performance, ensuring stable and efficient operation with notable advantages:
High Durability: Engineered for outdoor environments, the insulation and sheathing utilize specialized cross-linked polymer materials resistant to UV radiation, ozone, and weathering. They reliably transmit electricity in harsh conditions like deserts, coastal areas, and extreme temperatures, extending service life.
Superior Electrical Efficiency: Conductors utilize high-purity tinned copper with low resistivity, minimizing current transmission resistance losses. This enhances overall solar system generation efficiency, yielding significant energy cost savings in large-scale power plants.
Extended Service Life: Engineered for over 25 years of operation, premium materials and advanced manufacturing resist natural erosion and slow aging. Compared to standard cables, they deliver stable performance while reducing replacement costs and maintenance workload.
Extreme Environment Safety: Maintains high-temperature resistance, low-temperature flexibility, waterproofing, moisture resistance, impact resistance, and effective grounding shielding under extreme conditions like high/low temperatures, heavy rain, strong winds, and lightning strikes, ensuring power plant safety.
Easy Installation & Maintenance: Flexible structure and excellent pliability facilitate effortless routing. Simple connection methods using standardized connectors ensure high reliability, minimizing maintenance. Clear labeling and user-friendly connections reduce maintenance costs and downtime.

Summary

As a critical connection component in solar photovoltaic power generation systems, solar cables bear the vital mission of transmitting direct current. Though its definition is concise, it encompasses numerous complex and critical technical characteristics and structural designs. From specialized constructions tailored for solar systems to material selections adapted for harsh outdoor environments, from exceptional electrical performance and environmental resilience to diverse types and extensive application scenarios, solar cables play an indispensable role in the development of the solar industry.