TECHNICAL SPECIFICATION FOR THHN (THERMOPLASTIC HIGH HEAT RESISTANT NYLON COATED) CABLE
1. SCOPE
This specification covers single-conductor, annealed copper, thermoplastic-insulated, nylon-jacketed building wire rated 600V for use in dry and damp locations at temperatures up to 90°C (194°F) in dry locations and 75°C (167°F) in damp/wet locations.
2. APPLICABLE STANDARDS
- UL 83: Thermoplastic-Insulated Wires and Cables
- ASTM B3: Soft or Annealed Copper Wire
- ASTM B8: Concentric-Lay-Stranded Copper Conductors
- NFPA 70 (NEC): National Electrical Code
3. CONSTRUCTION
3.1 Conductor
- Material: Annealed copper, 99.9% conductivity
- Stranding: Solid or stranded per ASTM B3/B8
- Class: Class B (stranded) or Class A (solid)
- Sizes: 14 AWG (2.08 mm²) to 1000 kcmil (507 mm²)
3.2 Insulation
- Material: Polyvinyl Chloride (PVC)
- Temperature Rating: 90°C dry / 75°C wet
- Thickness: Comply with UL 83 minimum requirements
- Color Coding: Black, white, red, blue, green, etc. as per NEC
3.3 Outer Jacket
- Material: Nylon (Polyamide)
- Thickness: 0.004" (0.10 mm) minimum
- Features: Abrasion-resistant, oil-resistant
4. ELECTRICAL CHARACTERISTICS
- Voltage Rating: 600V
- Insulation Resistance: ≥ 20 MΩ/km at 20°C
- Dielectric Strength: 2000V AC for 5 minutes (no breakdown)
5. PHYSICAL PROPERTIES
- Flame Resistance: Passes UL VW-1 vertical flame test
- Cold Bend: No cracks at -25°C (-13°F)
- Heat Shock: No cracks after 16h at 121°C (250°F)
- Crush Resistance: ≤ 50% deformation at 2000 N force
6. TEST REQUIREMENTS
- Conductor Resistance: Per ASTM B3/B8
- Spark Testing: 100% production line testing
- Insulation Integrity: Water immersion test per UL 83
- Marking Durability: Rub test per UL 2556
7. MARKING & PACKAGING
- Surface Printing:
- Manufacturer's name/logo
- "THHN" or "THHN/THWN-2"
- AWG/kcmil size
- Voltage rating (600V)
- Temperature rating (90°C)
- Packaging:
- Wooden reels or coils with moisture-resistant wrapping
- Minimum bending radius: 6× overall diameter
8. INSTALLATION GUIDELINES
- Ambient Temperature: -40°C to 90°C
- Bending Radius: ≥ 5× cable diameter
- Conduit Fill: Per NEC Chapter 9 Table 1
- Pulling Tension: ≤ 0.008 lbf/circular mil cross-section
9. WARRANTY
- 10-year limited warranty against material/workmanship defects
10. REFERENCE STANDARDS
- UL 83
- ASTM B3/B8
- NEC 2023
- ICEA S-95-658