Appearance inspection: Good THHN/THWN/2 wires and cables should have a neat, smooth appearance, no obvious defects, and uniform color. High quality wires have the characteristics of tight packaging and clear handwriting. The surface of the wire has wire THHN models, such as 6 THHN wire, 12 THHN wire, 10 THHN wire, and 14 THHN wire
