When choosing building wire for commercial, industrial, or residential projects, contractors often face the question: XHHW vs THWN – which wire should you use?
Both are widely used for power distribution and branch circuits, but they differ in insulation material, moisture resistance, temperature ratings, and applications. In this guide, we’ll break down the differences between XHHW and THWN to help you make the right choice for your project.
xhhw vs thwn
What Is XHHW Wire?
XHHW stands for Cross-Linked High Heat-resistant, Water-resistant. This wire uses XLPE (Cross-linked Polyethylene) insulation, which offers superior durability and thermal resistance.
Key Features:
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Insulation: XLPE (cross-linked polyethylene)
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Voltage Rating: 600V (XHHW) / 1000V (XHHW-2)
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Temperature Rating:
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XHHW: 90°C dry / 75°C wet
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XHHW-2: 90°C dry & wet
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Moisture Resistance: Excellent
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Typical Use: Wet locations, underground conduit, industrial environments
What Is THWN Wire?
THWN stands for Thermoplastic Heat and Water-resistant Nylon-coated. It features PVC insulation with a nylon jacket and is commonly dual-rated as THHN/THWN.
Key Features:
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Insulation: PVC with a nylon coating
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Voltage Rating: 600V
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Temperature Rating:
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THWN: 75°C wet
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THWN-2: 90°C wet and dry
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Water Resistance: Good
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Typical Use: Indoor wiring, conduit systems, panel wiring
XHHW vs THWN: What Are the Main Differences?
| Feature | XHHW / XHHW-2 | THWN / THWN-2 |
|---|---|---|
| Insulation Type | XLPE (cross-linked polyethylene) | PVC (thermoplastic) with nylon jacket |
| Jacket | No nylon jacket | Nylon-coated for abrasion resistance |
| Water Resistance | Excellent (esp. XHHW-2) | Good (better with THWN-2) |
| Temp Rating | 90°C dry & wet (XHHW-2) | 75°C wet / 90°C dry (THWN), 90°C wet/dry (THWN-2) |
| Flexibility | Slightly stiffer | More flexible |
| UV Resistance | High | Moderate to high |
| Typical Use | Outdoor, wet, underground | Indoor, conduit, control panels |
Which Is Better: XHHW or THWN?
The best wire depends on the installation environment:
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Choose XHHW/XHHW-2 if:
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You’re wiring in wet, corrosive, or underground locations
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You need higher thermal and chemical resistance
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Long-term durability and moisture protection are a priority
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Choose THWN/THWN-2 if:
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The wiring is mostly indoor or in conduit
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You need greater flexibility and easier pulling
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You want a cost-effective solution for general applications
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Is XHHW the Same as THWN?
No, they’re not the same. While both are rated for wet and dry environments (especially in their '-2' versions), their insulation materials, flexibility, and durability differ. XHHW’s XLPE insulation gives it superior moisture, heat, and chemical resistance, whereas THWN’s thermoplastic insulation provides more flexibility and ease of use in conduit.
Need Help Choosing the Right Building Wire?
At TOT Wire & Cable, we carry a full range of XHHW, XHHW-2, THHN, and THWN-2 copper and aluminum wires. Whether you’re wiring a commercial facility or upgrading an industrial system, we can help you select the best cable for your application.
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