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Photovoltaics • DC • Cable

Oblicz przekrój kabla PV DC

Wymagany przekrój kabla DC dla kabli PV na podstawie prądu, długości i spadku napięcia.

Wartości obliczeń

PV cables are mostly copper

Uwaga: Ten kalkulator podaje jedynie techniczne oszacowanie. W instalacjach elektrycznych należy dodatkowo sprawdzić normy, środki ochrony, sposób ułożenia, temperaturę otoczenia, grupowanie, zabezpieczenia i dane producenta.

Zastosowany wzór

A = (2 × L × I) / (κ × ΔU)

ΔU = U × voltage drop% ÷ 100

For DC, the positive and negative conductors are accounted for with a factor of 2.

Najczęściej zadawane pytania

Why the factor 2 for DC?

The current flows through both the positive and negative conductor. That's why the one-way length is calculated with both the outgoing and return conductor accounted for.

What voltage drop is reasonable?

For PV DC cables, low voltage drop values are often targeted, for example around 1 percent.

Can I use this calculator for real PV planning?

It serves as a guideline. PV standards, protection concept, temperature, installation and manufacturer specifications must be checked.

Practical guidance

Check PV string cable size for DC voltage drop

String current flows between array and inverter; factor 2 includes positive and negative conductor paths.

Input values explained

Prąd
Enter the expected operating current, not a fuse rating. Motors and electronic power supplies may draw much higher starting or peak currents.
Cable length
Enter the one-way distance from supply point to load. The required return path is already represented by the selected formula.
Napięcie
Enter the operating DC voltage of the complete PV string at its working point, not the voltage of one module. Check maximum open-circuit voltage separately.
Permitted voltage drop
This percentage limits the calculated voltage loss. It is a design assumption and must suit the circuit and applicable requirements.
Conductivity κ
κ is the calculation value for the conductor material. Common approximations are 58 for copper and 37 for aluminium; heating increases actual resistance.

Example: 12 A, 600 V and 25 m

At 12 A, 600 V, 25 m one-way copper and 1% voltage drop, 6 V is available.

A = (2 × 25 × 12) ÷ (58 × 6) ≈ 1.72 mm²

Napięcie drop points to 2.5 mm². PV cable ampacity, DC rating, environment and connector system still need checking.

Treat PV DC voltage safely

String voltage varies with temperature. Maximum cold-weather open-circuit voltage is critical for insulation and equipment ratings.

Calculation limits

  • Maximum DC voltage, short-circuit current and safety factors are not checked.
  • UV exposure, routing, connectors and inverter requirements are excluded.