How Cable Size Affects Solar Cable Price (2.5–10mm² Comparison)

When sourcing PV wiring for residential, commercial, or utility-scale installations, solar cable price is often the first factor buyers compare. But many buyers overlook how strongly cable size (cross-sectional area) influences performance, durability, and long-term project cost. As a professional solar cable manufacturer with stable large-scale production capacity, we often help customers choose the correct cable size so they avoid paying more than necessary while still maintaining system safety.

This technical guide compares 2.5mm², 4mm², 6mm², and 10mm² solar cable sizes, explaining exactly why prices differ and what factors matter most in long-term system performance.

1. Why Cable Size Matters in PV Installations

Solar cables handle DC current from PV modules to inverters or combiner boxes. As cable diameter increases, the conductor area increases as well, directly affecting:

·Current-carrying capacity

·Voltage drop

·Heat resistance

·Installation distance and layout flexibility

Larger cables can safely carry more current with less power loss, but they also require more copper or aluminum—making solar cable price rise accordingly.

For most string systems, 4mm² and 6mm² are the most common, while 10mm² is used when distance is long or current is high.

2. Cable Size vs. Solar Cable Price: What Actually Changes?

The relationship between size and price is not linear. The cost gap between 2.5mm² and 4mm² is usually small, but the jump to 6mm² and 10mm² is more noticeable.

Below is a simplified explanation of why the price increases as cross-section increases.

2.1 Conductor Material (Copper / Tinned Copper / Aluminum)

Conductor cost can represent 60–75% of solar cable price.

A 10mm² cable contains roughly four times the copper mass of a 2.5mm² cable.

Tinned copper, common in PV systems, increases cost due to extra processing.

This is why cable size is one of the most significant pricing variables.

2.2 Insulation & Sheath Thickness

Larger cable sizes require thicker layers of XLPE, cross-linked insulation, and UV-resistant sheathing. Because solar cables must withstand:

·90°C continuous operating temperature

·−40°C to +120°C environment

·Outdoor UV exposure

·Ozone and humidity

Insulation volume grows along with conductor size, further pushing the cost upward.

2.3 Rated Voltage & Standards Compliance

PV cables typically meet IEC 62930, EN 50618, or UL 4703.
Higher cable sizes often require:

·Stricter spark-test thresholds

·Thicker insulation

·Larger conductor stranding

These add manufacturing steps, which raises the solar cable price.

2.4 Production Complexity for Larger Sizes

From drawing thicker conductors to controlling extrusion uniformity, larger cable sizes require more precise production control. A manufacturer with mass production equipment and automated extrusion lines can maintain stable pricing, especially for bulk orders.

This is why ordering from a true solar cable manufacturer—not a trader—ensures more consistent pricing across all cable sizes.

3. Cable Size Comparison: 2.5mm² vs. 4mm² vs. 6mm² vs. 10mm²

Here is how each cable size typically performs in PV installations:

2.5mm² Solar Cable

·Suitable for short residential runs

·Lowest cost

·Higher voltage drop over distance

·Rare in commercial installations today

4mm² Solar Cable (Most Common)

·Standard size for rooftop arrays

·Balanced price vs. performance

·Compatible with most MC4 connectors

·Low resistance and stable performance

6mm² Solar Cable

·Ideal for longer runs or higher string current

·Lower voltage drop improves system efficiency

·Price increase noticeable but justified for larger systems

10mm² Solar Cable

·Used in ground-mount arrays, long DC runs, or high-current layouts

·Lowest resistance & best thermal performance

·Higher solar cable price due to conductor mass

·Long-term ROI is superior in large installations

4. How Bulk Ordering Reduces Solar Cable Price

A professional manufacturer with continuous large-scale production can offer lower prices through:

·Raw material batch purchasing

·Automated production lines

·Lower labor cost per meter

·Fewer connector compatibility issues

·Quality control that reduces installation failures

For project developers, EPCs, and distributors, ordering in bulk dramatically improves cost structure and ensures consistent inventory.

5. Choosing the Right Solar Cable Size for Your Project

To optimize solar cable price without sacrificing quality, consider:

·Current output of PV strings

·Length of cable runs

·Local safety codes

·Voltage drop limits (typically ≤3%)

·Future expansion possibilities

Selecting the correct size at the start reduces long-term energy loss and maintenance cost.

Conclusion

Choosing the right cable size is one of the most effective ways to control solar cable price without compromising system reliability. Larger sizes such as 6mm² and 10mm² cost more due to conductor volume, insulation thickness, and production complexity, but they deliver measurable gains in electrical performance over long distances.

As a professional solar cable manufacturer with stable mass-production capability, we provide consistent quality and competitive pricing for all cable sizes, ensuring reliable supply for distributors, EPC contractors, and solar project developers.

If you need technical recommendations or custom-length PV cable for bulk ordering, our engineering team is ready to assist.

References

Kersten, F., Engelhart, P., Müller, J., & Kenny, R. P. (2012). Impact of module and system design on PV system energy yield. Energy Procedia, 27, 158–165.