How do you identify conductor size from markings like 10 AWG THHN?

• A. The number denotes gauge size; AWG value, THHN indicates insulation; refer to ampacity tables for current rating.
• B. The numbers indicate the number of strands in the conductor.
• C. THHN indicates the conductor's temperature rating; the number shows insulation class.
• D. The markings specify the vendor and date only.

Answer: (C)

The size shown is the gauge. The number is the wire’s cross‑section that corresponds to its gauge, and AWG indicates the American Wire Gauge system. THHN is the insulation type. So, 10 AWG THHN means you have a 10-gauge conductor with THHN insulation. To learn the current-carrying capability, you don’t rely on the number alone; you consult ampacity tables that account for the gauge, the insulation type (THHN), and the temperature rating (often shown elsewhere, e.g., 90°C). The markings here don’t indicate the number of strands or vendor/date. Those other details aren’t identified by this marking.