With the global expansion of photovoltaic (PV) power systems, the selection of electrical wires and cables is critical for system safety, efficiency, and longevity. Among numerous cable types, XHHW-2 wires stand out for their excellent heat resistance, chemical resistance, and UV stability, making them the preferred choice for PV wiring projects. This article provides a detailed overview of XHHW-2 wire specifications, installation methods, practical applications, and comparisons with other common wires such as THWRHH, RHW, RHW-2, helping engineers, procurement specialists, and installation teams make informed choices.
What Is XHHW-2 Wire
XHHW-2 is a single-core or multi-core wire with cross-linked polyethylene (XLPE) insulation and a thermoplastic polyolefin outer sheath. Its designation is explained as follows:
- X: Cross-linked polyethylene insulation (XLPE)
- HH: High heat rating (90℃)
- W: Suitable for wet locations
- 2: Second-generation product with improved heat and moisture resistance
XHHW-2 wires feature high-temperature tolerance (up to 90℃), moisture resistance, chemical resistance, and UV stability. They are ideal for outdoor PV systems, rooftop installations, and underground conduits.
XHHW-2 Wire Specifications and Selection
Common Specifications
| Model | Conductor Material | Rated Voltage | Application | Notes |
|---|---|---|---|---|
| XHHW-2 12 AWG | Copper | 600V | Rooftop PV wiring, indoor/outdoor circuits | Single-core |
| XHHW-2 10 AWG | Copper | 600V | PV module string and inverter connections | Single-core |
| XHHW-2 8 AWG | Copper | 600V | Main trunk line, medium PV systems | Single-core |
| XHHW-2 6 AWG | Copper | 600V | High-power PV arrays | Single-core |
| XHHW-2 4 AWG | Copper | 600V | Trunk from combiner box to inverter | Single-core |
Applications by Wire Gauge
- 12 AWG: Ideal for short connections between PV modules; flexible for rooftop wiring
- 10 AWG: Suitable for small-to-medium PV string circuits
- 8 AWG: Used for main trunk lines in medium-scale PV projects
- 6–4 AWG: Recommended for large-scale PV power plants, connecting combiner boxes to inverters
Installation Requirements and Methods
Suitable Environments and Routing
- Applicable for indoor, outdoor, underground conduit, and cable tray installations
- Avoid direct contact with sharp objects or corrosive substances
- Ensure adequate heat dissipation for high-temperature areas or rooftop installations
Bending Radius and Securing
- Small gauges (≤10 AWG): Minimum bending radius ≥ 6× wire diameter
- Large gauges (≥6 AWG): Minimum bending radius ≥ 8× wire diameter
- Use cable ties or clamps to secure wires without compressing the sheath
Termination
- Strip lengths should match terminal requirements
- Use appropriate crimp terminals or plug connectors
- Avoid excessive copper exposure that may cause short circuits
Safety and Standards
- Compliant with UL 4703 and NEC (National Electrical Code)
- Suitable for long-term operation in wet or mildly corrosive environments
- Flame-retardant properties meet PV system fire safety requirements
Comparison With Other Common Cables
XHHW-2 Vs. THW
| Feature | XHHW-2 | THW |
|---|---|---|
| Heat Rating | 90℃ | 75℃ |
| Wet Location Performance | Excellent | Good |
| UV Resistance | Excellent | Limited |
| Flexibility | High, easy rooftop installation | Moderate, stiffer |
| Applications | PV strings, rooftop and underground | Wet locations, conduit use |
XHHW-2 Vs. RHH
| Feature | XHHW-2 | RHH |
|---|---|---|
| Heat Rating | 90℃ | 90℃ |
| Wet Location Performance | Excellent | Limited |
| UV Resistance | Excellent | Moderate |
| Flexibility | High, easy rooftop installation | Thicker insulation, less flexible |
| Applications | PV strings, rooftop and underground | Dry locations, industrial wiring |
XHHW-2 vs. RHW / RHW-2
| Feature | XHHW-2 | RHW / RHW-2 |
|---|---|---|
| Moisture Resistance | Excellent | Good |
| Heat Rating | 90℃ | 75–90℃ |
| UV Resistance | Excellent | Moderate |
| Installation Flexibility | High | Medium |
| PV System Compatibility | High | Medium |
These comparisons show that XHHW-2 offers superior moisture resistance, UV stability, and flexibility for rooftop and outdoor PV applications compared to THW,RHH or RHW series.
Product Advantages
Comprehensive Wire Options
- We produce a full range of UL electrical wires and cables, including THHN, THW, MC Cable, AC Cable, and more. Full details are available in our UL wire catalog.
Compliance with North American Market
- XHHW-2 wires fully comply with North American standards, meeting electrical requirements for PV installations in the US, Canada, and beyond.
Complete Specifications
- From 12 AWG to 4 AWG, all standard models are available, covering the needs of various PV project scales.
Fast Delivery
- Quick shipping supports both small and large orders, ensuring timely project completion.
Technical Support
- Professional pre-sale and post-sale support ensures smooth installation and reliable operation.
Global Collaboration
- Years of manufacturing and export experience, with partners worldwide, guarantee stable and reliable supply.
UL Certification
- All products are UL certified, ensuring international safety and quality compliance.
Customization
- Available in various colors, with customizable material, specification, length, color, performance, labeling, and packaging to meet project-specific requirements.
Practical Applications in PV Projects
- Rooftop PV Systems: XHHW-2 wires connect PV modules with high UV and temperature resistance for long-term stability
- Large Ground-Mounted PV Plants: 6–4 AWG XHHW-2 wires used for main trunk lines ensure efficient energy transmission
- Combiner Box to Inverter Wiring: Flexible XHHW-2 wires simplify conduit routing and reduce installation complexity
- Wet or Corrosive Environments: Suitable for underground or rooftop exposure to water, ensuring long-term durability
Installation Considerations
- Avoid prolonged direct sunlight; consider metal trays or protective conduits
- Maintain proper bending radius during installation
- Ensure waterproofing at wire terminations
- Regular inspections and prompt replacement if sheath damage occurs
Overview
With superior heat, moisture, and UV resistance, along with high installation flexibility, XHHW-2 wires are the preferred choice for PV wiring. Compared with THWRHH or RHW series, XHHW-2 provides better stability and lifespan in rooftop, underground, and large PV installations. Its wide specification range, UL certification, and customization capabilities allow engineers to select the optimal wire for safe, efficient, and long-term PV system operation.
Company Information
Dongguan Greater Wire & Cable Co., Ltd.
- Tel / WhatsApp / WeChat: +86 135 1078 4550 / +86 136 6257 9592
- Email: manager01@greaterwire.com
This article provides a comprehensive reference for selecting XHHW-2 wires in PV projects, supporting safe, reliable, and efficient system installation.