THHN/THWN wire is a single-conductor, stranded copper wire with PVC insulation and a nylon outer jacket, designed for heavy-duty electrical distribution.
• Voltage rating: 600 volts
• Temperature rating:
o 90°C (dry locations – THHN)
o 75°C (wet locations – THWN)

Stranded Wires (MCM Sizes):
MCM (Thousand Circular Mils / kcmil) refers to very large conductor sizes used for extremely high current applications.
• Typical sizes: 250 kcmil, 300 kcmil, 350 kcmil, 500 kcmil and above
• Constructed from numerous fine copper strands for improved flexibility at large diameters

Key Features:
• Designed for very high ampacity (current-carrying capacity)
• Flexible for its size, but still requires special handling and bending radius
• Suitable for long-distance and high-load power transmission
• Requires heavy-duty lugs and termination equipment

Construction:
• Conductor: Stranded annealed copper (large kcmil sizes)
• Insulation: Heat-resistant thermoplastic PVC
• Outer Jacket: Nylon coating for:
o Superior abrasion resistance
o Protection against oil, chemicals, and moisture
o Smooth surface for easier conduit pulling

Typical Applications:
MCM-size THHN/THWN stranded wires are used in:
• Main service entrance conductors
• Primary feeders in commercial and industrial buildings
• Power distribution between transformers and switchgear
• Large motor installations and heavy equipment
• Utility and infrastructure projects

Summary:

THHN/THWN 600V 90°C stranded wire (MCM sizes) is an extra-large, high-capacity copper conductor used for major electrical distribution systems, capable of carrying very high current safely in demanding environments.