Product Overview

25mm DC Solar Cable is the heaviest conductor in the TUV solar cable series, purpose-built for DC trunk lines and main feeder circuits in large-scale photovoltaic installations. At this cable size, the job is no longer string wiring or mid-level collection - it is power transmission. The cable carries the aggregated output of entire array sections across distances where every fraction of a percent in line loss affects project economics.

With a 25mm² stranded tinned copper conductor and dual-layer cross-linked insulation, it delivers the lowest resistance per meter of any cable in the range. For utility-scale solar farms, large industrial plants, and centralized inverter architectures, this is the cable that protects energy yield at the point where lighter sizes simply cannot do the job.

Technical Parameters

Parameter	Specification
Conductor Size	25 mm²
Conductor Material	Tinned copper, multi-stranded
Cable Type	Single-core PV DC cable
Rated Voltage	1000V AC/1500V DC
Insulation	Electron-beam cross-linked halogen-free compound
Outer Sheath	UV-stabilized halogen-free compound
Temperature Range	-40°C-90°C
Short-Circuit Temperature	250°C (5s)
Min. Bending Radius	4× outer diameter
Approx. Outer Diameter	11.5–12.5 mm
Approx. Weight	~310 kg/km
Flame Performance	Low smoke, halogen-free, flame-retardant
Color	Black, red, or custom
Certification Basis	TUV PV cable standard

Core Uses

DC Trunk Lines and Main Feeders

25mm cable serves as the backbone of DC power routing in large installations. It connects combiner box outputs to inverter stations, DC distribution cabinets, or transformer-coupled conversion equipment, carrying the aggregated current of multiple string groups over distances that would cause unacceptable losses with lighter conductor.

Long-Distance DC Transmission

When equipment placement creates cable paths exceeding 60 to 100 meters, 25mm cable keeps voltage drop within the limits that project economics demand. This is the norm in ground-mounted solar farms where inverter stations sit centrally and array fields extend outward in every direction.

High-Current Storage Circuits

In large-scale solar-plus-storage projects, the DC circuits between battery racks, DC buses, and power conversion systems can carry substantial current. 25mm cable provides the conductor mass these circuits require for safe and efficient operation.

Application Scenarios

Utility-Scale Solar Farms

In megawatt-class solar farms, 25mm cable forms the main DC collection backbone. It connects field combiner boxes to central inverter stations across distances that would bleed energy with lighter cable. Beyond electrical performance, its mechanical robustness withstands the realities of large-scale field installation, trenching, conduit pulling, and the general handling demands of construction sites that cover hectares of open ground.

Industrial Facilities with Remote Inverter Rooms

Large factories and industrial complexes sometimes place inverter equipment in dedicated electrical rooms far from the rooftop array, across the building, down a riser, through a cable tray, and into a switchgear room. 25mm cable bridges these building-length routes efficiently, maintaining transmission quality where lighter cable would quietly waste energy over every meter of the path.

Centralized Inverter Architecture

Projects using centralized inverter topology such as where one or a few large inverters serve the entire array, concentrate DC current into fewer, heavier circuits. These trunk lines are exactly what 25mm cable is designed for. It provides the conductor mass needed to handle high aggregate current without excessive heating, and its lower resistance per meter directly improves the round-trip efficiency of the DC side.

Voltage Drop Reference

The following figures provide general guidance for preliminary cable selection. Actual values depend on conductor temperature, installation method, and ambient conditions.

Current	One-Way Distance	Approx. Voltage Drop
80 A	50 m	~2.9 V per conductor
80 A	100 m	~5.8 V per conductor
100 A	50 m	~3.6 V per conductor
100 A	100 m	~7.2 V per conductor

These values are based on standard conductor resistance at 20°C. At higher operating temperatures, actual voltage drop will be somewhat greater.

Selection Guide

25mm DC Solar Cable is not a general-purpose cable - it is a trunk-line cable. Choose it when the circuit is a main DC feeder, not a string lead or mid-level collection line. Specifically:

Aggregated circuit current exceeds what 16mm cable handles within thermal limits
Cable routing distance is long enough that voltage drop becomes a meaningful design constraint
The project uses centralized inverter architecture with heavy DC collection
Energy yield modeling shows that conductor loss in lighter cable sizes reduces project return

For standard string wiring, module interconnection, or short residential runs, the lighter sizes in the TUV range (4mm–10mm) are more appropriate. 16mm serves as the intermediate option for circuits that need more than collection cable but less than full trunk-line capacity.

Quality and Compliance

Product is manufactured under TUV photovoltaic cable requirements with factory quality control covering:

Raw material incoming inspection
Conductor resistance and dimensional verification
Insulation thickness and concentricity testing
Voltage withstand and insulation resistance testing
Finished product sampling and visual inspection

Specific test reports, compliance documentation, and certification materials can be coordinated based on project requirements and destination market.

Shipping and Handling

25mm cable is supplied on wooden drums or heavy-duty reels suited for sea freight and project site delivery. At approximately 310 kg per kilometer, packaging and transport planning should account for handling equipment at the receiving site. Standard lengths, custom cutting, and private-label marking are available for project and OEM orders.