What Are RHW-2 and RWU90 Cables?

RHW-2 and RWU90 are high-performance copper cables designed for power distribution and industrial applications, rated for 1kV or 2kV. RHW-2 (Rubber Heat and Water-resistant, Type 2) is a thermoset-insulated cable suitable for wet and dry locations, offering heat resistance up to 90°C. RWU90 (Rubber Weather and Underground, 90°C) is an enhanced version optimized for direct burial and harsh outdoor environments, with superior moisture, corrosion, and UV resistance. Both comply with standards such as UL 44, UL 854, CSA C22.2 No. 38, and NEC, making them versatile for solar, industrial, and utility applications, similar to THHN, XHHW, or 6 AWG cables discussed previously. Their robust construction ensures reliable power transmission in demanding conditions.

Construction and Specifications

RHW-2 and RWU90 cables share similar construction but differ in environmental adaptability:

• Conductor: Stranded or solid copper (59.6 MS/m conductivity), typically 8 AWG to 750 kcmil, similar to 6 AWG or multi-conductor cables. Stranding enhances flexibility for conduit or burial applications.
• Insulation: Cross-linked polyethylene (XLPE), a thermoset material, provides heat resistance up to 90°C in wet or dry conditions, with superior dielectric strength compared to PVC used in THHN cables.
• Jacket: RHW-2 uses a durable XLPE jacket for wet/dry environments; RWU90 features a thicker XLPE jacket for direct burial, UV resistance, and protection against moisture and corrosion, akin to H07RN-F or marine cables.
• Voltage Rating: Both are rated for 600V, 1kV, or 2kV, supporting high-power applications like solar systems or industrial wiring.
• Standards: Compliant with UL 44 (RHW-2), UL 854 (USE-2), CSA C22.2 No. 38 (RWU90), and NEC, with additional certifications like RoHS and EPA 40 CFR Part 261 for environmental safety.

Specifications include ampacity per NEC tables (e.g., 65A for 6 AWG copper at 90°C) and resistance to oil, gasoline, and sunlight, making them suitable for harsh environments.

Key Differences Between RHW-2 and RWU90

While RHW-2 and RWU90 share core features, their differences cater to specific applications:

• Environmental Suitability: RHW-2 is designed for wet and dry locations, suitable for conduits, raceways, or cable trays; RWU90 is optimized for direct burial and outdoor exposure, with enhanced UV, moisture, and corrosion resistance, indicated by the “U” (Underground).
• Jacket Thickness: RWU90 has a thicker XLPE jacket for underground durability, while RHW-2’s jacket is sufficient for protected environments, similar to THHN vs. THWN differences.
• Applications: RHW-2 is versatile for indoor/outdoor wiring in conduits; RWU90 excels in underground service entrances or solar installations requiring weather resistance, akin to marine or cold temperature cables.
• Cost: RHW-2 is generally more economical for indoor or conduit-based installations; RWU90 is costlier due to its robust jacket and weather resistance, similar to H07RN-F vs. standard cables.
• Flexibility: Both offer flexibility due to stranded copper, but RWU90’s thicker insulation may reduce flexibility slightly, impacting installation in tight spaces.

RWU90 is often dual-rated as RHW-2/USE-2, offering versatility for both underground and conduit applications.

Applications of RHW-2 and RWU90

RHW-2 and RWU90 cables are used in various high-power and harsh-environment settings:

• Solar Energy: RWU90 is a common choice for photovoltaic (PV) systems, connecting panels to inverters due to its UV and waterproof capabilities, similar to 6 AWG or CCS cables. RHW-2 is used in protected solar wiring within conduits.
• Industrial: Both power motors, control systems, and lighting in factories, with RHW-2 in conduits and RWU90 for underground feeds, akin to trailing or multi-conductor cables.
• Utility: RWU90 serves as service entrance cables for underground power distribution, while RHW-2 supports overhead or conduit-based utility wiring, similar to MV or 6 AWG cables.
• Commercial: RHW-2 powers HVAC, lighting, and equipment in office buildings or retail spaces, while RWU90 is used for exterior or buried circuits, comparable to THHN or XHHW applications.
• Outdoor Infrastructure: RWU90 connects streetlights, pumps, or EV chargers in harsh climates, with resistance to moisture and UV, similar to cold temperature or marine cables.

Their versatility makes them suitable for applications requiring high reliability, akin to RHW or H07RN-F cables.

Installation and Safety Considerations

Proper installation and safety practices ensure RHW-2 and RWU90 cables perform reliably:

• Sizing: Match wire size to load per NEC ampacity tables (e.g., 40A for 8 AWG copper at 90°C) to prevent overheating, similar to 6 AWG or THHN cables.
• Environment: Use RHW-2 in conduits or cable trays for wet/dry locations; use RWU90 for direct burial or outdoor exposure to avoid insulation degradation, akin to THWN or H07RN-F cables.
• Grounding: Include a grounding conductor in conduit systems or ensure proper bonding for buried RWU90, per NEC, as discussed in grounding wire applications.
• Terminations: Use 90°C-rated connectors for both cables, ensuring secure connections to prevent arcing, per UL 44 and CSA standards.
• Installation Practices: For RWU90, bury at NEC-specified depths (e.g., 24 inches for direct burial) and use protective conduits for RHW-2 in exposed areas to prevent damage.
• Professional Installation: Engage licensed electricians to ensure NEC compliance, proper conduit sizing, and secure terminations, reducing risks like faults or corrosion.

These measures align with installation practices for LSOH, cold temperature, or trailing cables.

RHW-2 vs. RWU90 Comparison Table

The table below summarizes the key attributes of RHW-2 and RWU90 cables:

Note: Ampacity and specifications based on NEC 2020 and UL/CSA standards. Verify with NEC or electrician for specific conditions.

Tips for Choosing RHW-2 or RWU90

Selecting the appropriate cable ensures performance and cost-efficiency:

• Assess Environment: Choose RHW-2 for indoor or conduit-based installations in wet/dry conditions; select RWU90 for direct burial or outdoor exposure, similar to THWN or H07RN-F cables.
• Verify Ampacity: Select wire size per NEC tables (e.g., 65A for 6 AWG copper at 90°C) to match load and breaker, akin to 6 AWG or THHN cables.
• Consider Dual Ratings: Opt for RWU90 with RHW-2/USE-2 dual ratings for versatility in mixed environments, reducing inventory needs.
• Ensure Grounding: Include grounding conductors for safety, per NEC, as discussed in grounding applications.
• Check Standards: Confirm compliance with UL 44, UL 854, CSA C22.2 No. 38, or AS/NZS 5000 for safety and legal requirements.
• Calculate Voltage Drop: For runs over 50 ft, use voltage drop calculators to ensure efficiency, similar to 6 AWG or MV cables.
• Consult Professionals: Engage electricians for load calculations, burial depths, and NEC-compliant installations, as with household or H07RN-F cables.

These steps ensure reliable wiring, akin to selecting LSOH, cold temperature, or flat cables.

Conclusion

RHW-2 and RWU90 1kV/2kV copper cables are robust solutions for power distribution in demanding applications, from solar systems to industrial and utility wiring. RHW-2, with its XLPE insulation, excels in wet and dry environments within conduits, offering cost-effective versatility. RWU90, with a thicker, weather-resistant jacket, is ideal for direct burial and outdoor installations, providing superior UV, moisture, and corrosion resistance. Both cables, compliant with UL, CSA, and NEC standards, ensure reliable performance with proper sizing, grounding, and installation. By selecting RHW-2 for protected environments or RWU90 for harsh outdoor conditions, users can achieve safe, efficient power transmission, building on the reliability of cables like THHN, 6 AWG, H07RN-F, or cold temperature cables discussed previously.