🔗 Kalkulator Jatuh Tegangan Kabel PV
Periksa jatuh tegangan sisi DC dan rugi saluran string PV, verifikasi ampasitas kabel (1.25 × Isc), dan pilih penampang minimum yang tetap di bawah panduan jatuh tegangan 2%.
🔗 String & Cable
📊 Voltage-Drop Result
Untuk pemasang tenaga surya yang menentukan ukuran kabel dan konektor DC home-run.
Cara menghitungnya
· Hambatan dua arah: R = 2 × ρ × L ÷ A (ρ tembaga 0.0175 Ω·mm²/m).
· Jatuh tegangan: VD = I × R; VD% = VD ÷ V_string × 100.
· Pemeriksaan ampasitas: yang diperlukan ≥ I × 1.25; rating konektor (MC4) ≥ I × 1.25.
Standar yang dirujuk
| Standard | Scope |
|---|---|
| IEC 60364 | Instalasi listrik tegangan rendah (ampasitas kabel) |
| NEC 690 | Sistem fotovoltaik surya (ampasitas konduktor 1.25 × Isc) |
Contoh perhitungan — 13 A sepanjang 50 m → 1.42% pada 4 mm²
1. Arus string 13 A, jarak 50 m, 4 mm², tegangan string 400 V.
2. R = 2 × 0.0175 × 50 ÷ 4 = 0.44 Ω; VD = 13 × 0.44 = 5.7 V = 1.42%.
3. Ampasitas: 13 × 1.25 = 16.3 A ≤ 32 A (4 mm²) OK.
4. 1.42% berada dalam panduan 2% — 4 mm² sudah mencukupi.
FAQ
What voltage drop is acceptable in a PV DC cable?
Design practice limits total DC-side voltage drop to about 2% (IEC 60364 and common PV guidelines), split roughly 1% in the string cabling and 1% in the DC run to the inverter. Higher drop means lost energy — every 1% of drop is roughly 1% of lost annual yield. The calculator checks the drop and recommends the minimum cross-section.
How do I size a PV cable for ampacity?
PV DC cables must carry the string short-circuit current with a safety factor (usually 1.25x Isc, and 1.56x per NEC). For a 550 W module with Isc ~13.9 A and a two-parallel-string combiner, the combined current is ~35 A, so a 6 mm2 copper cable (rated ~40-45 A) is typical. The calculator verifies ampacity and derating.
Copper or aluminum for PV DC cabling?
PV string and DC cables are almost always copper because DC circuits are low-voltage and ampacity-sensitive; aluminium would need a much larger cross-section for the same drop. Copper is also easier to terminate on MC4 connectors. Aluminium appears only in long AC medium-voltage collector runs. The calculator defaults to copper for DC.
How long can a PV DC cable run be?
DC run length is limited by the 2% voltage-drop budget. For a 10 kW string at 500 V DC and 20 A, a 4 mm2 copper cable can run roughly 40-60 m before exceeding 2%. Longer runs need 6-10 mm2 cable or a higher system voltage. The calculator computes the maximum length for a given cross-section.
What DC cable type is used for solar arrays?
PV arrays use double-insulated, UV-resistant solar cable (H1Z2Z2-K / EN 50618, rated 1.5 kV DC and -40 to +90 deg C) for outdoor runs. Single-core copper, usually 4-6 mm2 for strings and 10-35 mm2 for DC mains. The calculator selects cable by ampacity and drop and cites the applicable standard.
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