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Ⅰ. Product Definition
Single-layer 1000V photovoltaic (PV) wire is a specialized cable designed for direct current (DC) transmission in solar power systems. Featuring a single insulation layer of cross-linked polyethylene (XLPE) or equivalent materials, this wire balances cost-effectiveness with reliable performance for medium-voltage PV applications up to 1000V DC.
Ⅱ. Core Structure & Materials
2.1 Conductor
Material: Oxygen-free copper (≥99.97%), tinned for corrosion resistance (stranded or solid core).
Common Sizes: 2.5mm² (14AWG), 4mm² (12AWG), 6mm² (10AWG), 10mm² (8AWG).
2.2 Insulation Layer
Material: Cross-linked polyethylene (XLPE)
Cross-linking method: Silane or electron beam (EB) curing.
Thickness: 0.76mm (14AWG) to 1.14mm (8AWG).
Key Properties:
Thermal stability: -40°C to +90°C.
Electrical strength: ≥20 kV/mm breakdown voltage.
Ⅲ. Technical Specifications
Parameter | Typical Values |
Rated Voltage | 1000V DC (compliant with UL 4703) |
Current Carrying Capacity (90°C) | 25A (2.5mm²) / 60A (10mm²) |
DC Resistance (20°C) | ≤7.41Ω/km (2.5mm²) / ≤1.83Ω/km (10mm²) |
Insulation Resistance | ≥100MΩ @ 500V DC |
Flame Retardancy | Meets VW-1 vertical flame test (UL 1581) |
UV Resistance | Passes 1000-hour xenon arc test |
Moisture Resistance | No degradation after 1000h at 85°C/85% RH |
Ⅳ. Advantages & Limitations
4.1 Key Advantages
Cost-Effective: 15–20% lower cost than double-layer cables.
Flexibility: Easier routing in tight spaces (bend radius ≥4× diameter).
Lightweight: Reduces installation labor for small to medium systems.
4.2 Limitations
Environmental Exposure: Not suitable for direct outdoor use without conduit (vulnerable to UV and abrasion).
Moisture Sensitivity: Requires sealed terminations in wet locations.
Mechanical Stress: Less durable than double-layer cables in high-friction areas.
Ⅴ. Applications
5.1 Ideal Use Cases
Residential Rooftop Systems: 1–10kW setups with conduit protection.
Indoor Wiring: Between inverters and electrical panels.
Temporary Installations: Construction sites or portable solar kits.
Conduit-Mounted Commercial Runs: Shorter distances (≤50m) in protected environments.
5.2 Not Recommended for
Direct burial or outdoor exposure without shielding.
High-moisture environments (coastal areas, rainforests).
Industrial settings with mechanical hazards (e.g., heavy machinery).
Ⅵ. Installation Guidelines
Termination:
Use UL-listed crimp terminals (e.g., ring terminals for solid core).
Ensure connectors are rated for 1000V DC (e.g., MC4 for solar applications).
Conduit Selection:
PVC conduit for outdoor runs (UV protection).
Metal conduit for fire-rated or industrial installations.
Temperature Derating:
At 40°C ambient, derate current by 80% (NEC Table 310.15(B)(2)(a)).
Grounding:
Green-insulated ground wires must comply with local codes (e.g., NEC 250.118).
Ⅶ. Certification & Compliance
UL 4703: Mandatory for PV applications in North America (includes temperature cycling and impact resistance tests).
NEC 2023 (Article 690): Requires separation from other circuits in conduit.
RoHS Compliance: Lead-free conductor and halogen-free insulation (optional for global markets).
Ⅷ. Comparison: Single-Layer vs. Double-Layer 1000V PV Wire
Feature | Single-Layer (XLPE) | Double-Layer (XLPE + TPE) |
Structure | Single insulation layer | Insulation + protective sheath |
Abrasion Resistance | Moderate (conduit required) | High (suitable for direct burial) |
UV Protection | Depends on XLPE additives | Enhanced via TPE sheath |
Lifespan | 10–15 years (protected) | 20–25 years (unprotected) |
Cost | (1.2–)2.5/m (2.5–10mm²) | (1.8–)3.2/m (2.5–10mm²) |
Ⅸ. 选型建议 (Selection Guide)
Residential 1–5kW Systems: 4mm² single-layer wire in PVC conduit.
Commercial 10–50kW Systems: 6–10mm² single-layer wire with metal conduit for fire safety.
Cost-Sensitive Projects: Prioritize solid-core single-layer cables over stranded designs.
Mild Outdoor Environments: Choose UV-stabilized XLPE single-layer wire with conduit.
Ⅹ. Maintenance & Longevity
Aging Prevention:
Inspect annually for sheath cracking (especially near heat sources like inverters).
Replace wires showing signs of brittleness or discoloration.
Expected Lifespan:
10–15 years in protected environments (indoor/conduit).
5–8 years in unprotected outdoor setups (without UV additives).
For critical applications, always request manufacturer datasheets to verify temperature ratings and certification logos (e.g., UL Mark). In outdoor or harsh environments, upgrading to double-layer PV cables is recommended for enhanced durability and safety.