What is RW90 Wire?

If you work in commercial construction, industrial manufacturing, or power distribution, chances are high that you’ve come across RW90 wire. Renowned for its extreme durability, high temperature resilience, and moisture resistance, RW90 is one of the most widely specified single-conductor building wires in industrial applications across North America.

In this guide, we break down what RW90 stands for, its technical specifications, where it is used, and how it compares to other building wires like XHHW-2 and THHN/THWN-2.

What does "RW90" Stand For?

The name RW90 is an acronym defined by CSA standards that outlines the cable’s core physical properties:

• R (Rubber / Thermoset): Historically referred to rubber insulation, but modern RW90 utilizes high-performance XLPE (Cross-Linked Polyethylene), a thermoset insulation that won’t melt or drip under heat.

• W (Water-Resistant): Indicates the wire is fully rated for wet, damp, or dry location installations.

• 90 (90°C Rating): The maximum continuous operating temperature rating of 90°C (194°F) in both wet and dry environments.

Key Technical Specifications

• Voltage Rating: Available in 600V and 1000V ratings depending on the application.

• Conductor Options: Available in Bare Copper or AA-8000 Series Aluminum Alloy, with stranded conductors for easy pull-through during installation.

• Insulation Type: XLPE (Cross-Linked Polyethylene) insulation provides superior resistance to abrasion, ozone, chemicals, and mechanical crushing.

• Temperature Limits: -40°C minimum installation/operating temperature up to 90°C continuous operating temperature.

• Flame/Smoke Tests: Often available in sunlight-resistant, direct burial, and Low Smoke Zero Halogen (LSZH) variants for specialized code compliance.

Common Applications for RW90

Because RW90 holds up exceptionally well in demanding conditions, it is commonly specified for:

1. Conduit & Raceway Pulls: Main power distribution lines pulled through conduit in commercial buildings, factories, and residential structures.

2. Underground Ducts & Wet Locations: Feeder runs routed through underground raceways subject to moisture accumulation.

3. Services & Feeders: Connecting utility transformers to main switchgear or branch distribution panels.

4. Cable Tray Systems: Industrial environments where power cables are exposed to potential chemical vapor or harsh environments.

RW90 vs. XHHW-2 vs THHN/THWN-2: What's the Difference

Key Takeaway: RW90 and XHHW-2 are functionally very similar—both utilize rugged XLPE insulation without a separate nylon jacket. However, RW90 is primarily a CSA-standardized designation widely specified in Canadian and cross-border construction projects, while XHHW-2 is the primary UL equivalent under the National Electrical Code (NEC).

Why Choose XLPE Insulation over PVC?

Unlike standard THHN wire which relies on a thermoplastic PVC insulation covered by a clear nylon skin, RW90 uses thermoset XLPE insulation.

Why does this matter on the job site?

• No Nylon Outer Skin to Tear: Pulling THHN through tight conduit bends can peel or nick the thin nylon jacket. RW90’s solid XLPE wall won't strip or compromise protection.

• Cold Weather Handling: RW90 remains pliable down to -40°C, meaning it won't snap or crack during cold-weather pulls.

• Higher Overload Tolerances: Thermoset insulation will not melt under short-circuit heat spikes.

Need RW90 or XHHW-2 for Your Next Job?

Whether you're pulling feeder lines for an industrial retrofit or sourcing wire for a commercial job site, Wire America supplies a full range of RW90 or XHHW-2 from sizes 14 AWG to 1000 MCM.   We can cut the material to the exact length you need on the majority of sizes and can get it on a truck for quick delivery.  

SHOP OUR RW90 / XHHW-2 BUILDING WIRE >>

Not sure which cable is right for you? Our team is here to help. Give us a call at (833) 268-8644 or email sales@wireamerica.com.

At Wire America, we believe in genuine conversation. You'll always talk with real people who understand that every project requires careful product selection. We're here to ensure you feel educated, confident, and great about your final purchase. Feel free to give us a call to discuss your project! You can reach us at: 833-268-8644

⚠️ Important Disclaimer: Safety and Compliance

Wire America provides this information as a guide only. Electrical installations must strictly adhere to the National Electrical Code (NEC) and all state, local, and jurisdictional requirements, which vary widely. Always consult a licensed electrician, electrical engineer, or the local inspecting authority before purchasing material or starting any electrical project. Wire America assumes no liability for the installation, use, or interpretation of these guides.