THHN/THWN wire is a single-conductor electrical wire made of stranded copper, insulated with heat-resistant PVC and protected by a nylon coating. It is widely used for heavy-duty electrical power distribution.
• Voltage rating: 600 volts
• Temperature rating:
o 90°C (dry locations – THHN)
o 75°C (wet locations – THWN)

Stranded Wires (Large Sizes)
Large-size stranded wires are designed for high-current applications and heavy electrical loads.
• Typical sizes: 38 mm² and above (can go up to 100 mm² or more)
• Made of many fine copper strands (Class B or higher stranding)
Key Features:
• Less flexible than small/medium wires, but still bendable compared to solid conductors
• Built for maximum ampacity (current-carrying capacity)
• Strong and durable for long-distance runs and heavy-duty installations
• Requires proper tools and techniques for bending and termination

Construction
• Conductor: Annealed copper, stranded (large cross-section)
• Insulation: Flame-retardant PVC (thermoplastic)
• Outer Jacket: Nylon (polyamide) for:
o High abrasion resistance
o Protection against oil, chemicals, and moisture
o Smooth pulling through conduits

Key Characteristics
• High heat resistance up to 90°C (dry conditions)
• Suitable for wet and dry environments
• Excellent electrical conductivity for heavy loads
• Long service life under demanding conditions

Typical Applications
Large-size THHN/THWN stranded wires are commonly used in:
• Main feeder lines and service entrance conductors
• Power distribution systems in large buildings
• Industrial plants and heavy machinery connections
• Transformers, switchgear, and panel boards
• Installation in conduits, cable trays, and ducts

Summary:

THHN/THWN 600V 90°C stranded wire (large size) is a heavy-duty copper conductor designed to carry large amounts of electrical current safely, with strong insulation and protection for industrial and high-power applications.