Polycab Solar DC Cables
Kamaxi Electricals supplies Polycab solar DC cables in red and black for rooftop, industrial and ground-mounted solar plants. These cables run from the PV modules to the array junction box, DCDB or inverter. Use the calculator below to pick the right size, check the voltage drop and work out the length, then request a quote.
DC cable size & length calculator
Size comparison (per cable run)
Your cable requirement
Current rating as per typical datasheet values in free air at up to 60 °C ambient, derated above 60 °C and for conduit / grouping. Design current = 1.25 × Isc × strings in parallel (IEC 62548). Voltage drop uses conductor resistance at about 70 °C.
Typical specifications
| Single core size | 4 sq mm | 6 sq mm | 10 sq mm |
|---|---|---|---|
| Conductor | Tinned annealed copper, class 5 flexible | ||
| Insulation / sheath | Electron-beam cross-linked halogen-free compound, UV resistant | ||
| Overall diameter (nominal) | 5.1 mm | 6.1 mm | 6.6 mm |
| Current rating in air | 55 A | 70 A | 98 A |
| Conductor resistance at 20 °C (max) | 5.09 Ω/km | 3.39 Ω/km | 1.95 Ω/km |
| Rated voltage | 1.5 kV DC (1.0/1.0 kV AC) | ||
| Operating temperature | -40 °C to +90 °C (conductor up to 120 °C for 20,000 h) | ||
Values are typical; refer to the manufacturer datasheet for the exact cable you order. Other sizes from 2.5 to 16 sq mm are available on request.
Which DC cable size do I need for a rooftop solar plant?
For most rooftop plants with 540-600 Wp panels, 4 sq mm solar DC cable is enough when each string runs directly to the inverter and the run is under about 40 m. Use 6 sq mm for longer runs, two strings in parallel, or when you want lower losses. The calculator above checks both current rating and voltage drop for your exact case.
Why should DC cable voltage drop be kept below 1.5%?
Every percent of voltage drop is energy lost for the life of the plant. Keeping DC voltage drop at or below 1 to 1.5% is common practice and keeps cable losses small compared with the cost of a larger size.
What is the difference between solar DC cable and normal wire?
Solar DC cable has tinned flexible copper and electron-beam cross-linked insulation that resists UV, ozone, heat and moisture for 25 years. Normal PVC wire degrades quickly on a roof and is not rated for 1.5 kV DC.
Do you supply red and black cable separately?
Yes. We supply red for positive and black for negative so polarity is easy to check during installation and maintenance. The calculator gives the length for each colour.
Where do you deliver?
Kamaxi Electricals is based in Rajkot, Gujarat. Share your site location in the quote request and we will confirm delivery and lead time.
