With the rapid development of global renewable energy, the scale of photovoltaic (PV) systems continues to expand. In ground-mounted PV plants, distributed PV systems, and large-scale energy storage stations, cables not only carry current but also ensure the long-term stable operation of the system. Especially in underground buried wiring applications, cables must have high resistance to heat, moisture, corrosion, and mechanical stress.
Among various cable types, RHW-2 cables stand out for their excellent heat resistance, water resistance, and corrosion resistance, making them a reliable choice for PV wiring. This article will analyze the feasibility of RHW-2 cables for buried PV wiring, outline practical installation considerations, and provide a comparison with commonly used THWN-2 cables, helping engineers, installers, and procurement professionals make informed decisions.
What is RHW-2 Cable?
RHW-2 stands for Rubber-insulated Heat and Water-resistant cable. It is designed to withstand high temperatures and moisture while ensuring long-term electrical safety. RHW-2 cables are rated up to 90°C, suitable for diverse PV environments.
Construction Features
RHW-2 cables consist of three main components:
- Conductor: Typically copper or aluminum, providing high conductivity and compliance with UL standards.
- Insulation: Cross-linked polyethylene (XLPE) or other high-performance materials offering excellent moisture resistance and electrical stability.
- Jacket: Even thickness, resistant to water, UV, and chemical corrosion, suitable for underground, surface, and exposed conditions.
Applications
RHW-2 cables are widely used in:
- Buried PV system wiring
- Ground and underground power transmission lines
- Building and industrial power distribution
- Harsh or high-humidity environments requiring reliable electrical performance
Their design ensures long-term reliable operation in various conditions, making them a core cable choice for PV systems.
Feasibility and Installation Considerations for Buried PV Wiring
Underground buried PV wiring demands high performance. RHW-2 cables excel in moisture resistance, corrosion resistance, mechanical strength, and temperature tolerance.
1.Moisture resistance: Ensures long-term operation in wet or soil-contact environments
2.Heat resistance: Rated up to 90°C for stable operation under sunlight or subsurface heat
3.Mechanical strength: Resistant to compression and bending, ideal for buried installation
4.UV resistance: Maintains long-term stability even when partially exposed
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Installation Considerations
To ensure long-term reliability, the following should be observed:
1.Burying Depth and Protective Layers
Select appropriate burial depth based on soil type and mechanical load. Cover cables with sand or protective conduits to prevent damage from rocks or excavation.
2.Bending Radius and Pulling Tension
While RHW-2 is flexible, minimum bending radius and maximum pulling tension must be followed to avoid conductor damage.
3.Joints and Terminations
All joints should be sealed with waterproof and corrosion-resistant materials to prevent moisture ingress.
4.Construction Environment
Avoid contact with corrosive substances; ensure soil backfill is compact and free of sharp objects.
5.Periodic Inspection and Maintenance
Regular electrical testing and on-site inspection can detect potential issues early, ensuring system reliability.
By following these best practices, RHW-2 cables can provide stable and safe operation for underground PV wiring and extend system lifespan.
Comparison: RHW-2 vs. THWN-2
THWN-2 cables also offer 90°C heat and moisture resistance but have PVC insulation with slightly lower long-term durability in wet or corrosive soil. THWN-2 is more suitable for conduit wiring rather than direct burial.
| Feature | RHW-2 | THWN-2 |
|---|---|---|
| Moisture Resistance | Excellent | Good |
| Corrosion Resistance | Excellent | Moderate |
| Flexibility | Good | Higher |
| Suitable Environment | Direct burial, wet, exposed | Conduit, wet |
For buried PV wiring, RHW-2 cables provide superior reliability, especially for long-term moisture and corrosion resistance.
RHW-2 Cable Specifications and Application Scenarios
RHW-2 cables are available from AWG 14 to 1000 kcmil, covering different PV load requirements.
Technical Specifications
| Model | Voltage Rating | Conductor Material | Conductor Area | Insulation | Jacket | Temperature Rating | Suitable Environment |
|---|---|---|---|---|---|---|---|
| RHW-2 12 AWG | 600V | Copper | 3.31 mm² | XLPE | PVC/XLPE | 90°C | Buried/Wet |
| RHW-2 6 AWG | 600V | Copper | 13.3 mm² | XLPE | PVC/XLPE | 90°C | Array to inverter buried wiring |
| RHW-2 2/0 AWG | 600V | Copper | 67.4 mm² | XLPE | PVC/XLPE | 90°C | Main transmission line for large PV plant |
Application Scenarios
- Small sizes (AWG 14–8): Internal wiring for combiner boxes and inverters
- Medium sizes (AWG 6–2/0): Buried wiring from arrays to combiner systems
- Large sizes (250 kcmil–1000 kcmil): Main transmission lines for large PV plants
Proper sizing optimizes wiring safety and system efficiency.
Case Studies and Wiring Illustration
Case 1: Ground-Mounted PV Plant
RHW-2 cables connect inverters and combiner boxes underground, enduring soil moisture and mechanical stress.
Case 2: Rooftop PV Project
Some lines run through conduits; RHW-2 can be paired with THWN-2 for long-term stability in underground or partially exposed sections.
Case 3: Large Energy Storage Station
RHW-2 performs reliably in underground battery storage, maintaining insulation and mechanical strength under high humidity.
Wiring Illustration (Descriptive)
- Combiner Box to Inverter: RHW-2 cables are laid in pre-excavated trenches with sand cover to prevent rock damage.
- Main Transmission Lines: Large RHW-2 cables are buried in sand bedding or concrete conduits for stable long-term transmission.
- Bends and Joints: Follow minimum bending radius and seal joints with waterproof materials to ensure safety.
Our Advantages
Dongguan Greater Wire & Cable Co., Ltd. has years of experience producing UL-certified wires and cables, including THHN, THW, MC Cable, AC Cable, and more. Our products meet American market standards and guarantee consistent quality.
We offer a complete range from small to large sizes, suitable for arrays, combiner boxes, inverters, and main transmission lines. Customers can select optimal models for safe and efficient PV system wiring.
We provide fast delivery for both small and bulk orders. Our professional technical team offers pre-sale and after-sale support, assisting customers with design, selection, and installation, ensuring peace of mind throughout the project.
With extensive international manufacturing and export experience, our partners span the globe. We provide full customization options, including materials, sizes, lengths, colors, performance, labeling, and packaging, delivering efficient and cost-effective solutions for diverse project needs.
Company Information
Dongguan Greater Wire & Cable Co., Ltd.
- Tel/WhatsApp/Wechat: +86 135 1078 4550 / +86 136 6257 9592
- Email: manager01@greaterwire.com