In modern building electrical systems, the performance of wires and cables directly affects the safety and reliability of the entire project. With the expansion of building scale and the increase in electrical load, the performance of traditional PVC insulated wires in high-temperature, humid, or high-load environments is gradually failing to meet the demands. At this point, XHHW wires (Cross-linked Heat and Water Resistant Wire) are used in building electrical systems due to their excellent heat resistance, moisture resistance, and insulation properties.

THWN and THWN-2 are common electrical conductor types used in building wiring systems, conforming to the National Electrical Code (NEC) and UL certification standards. Both use copper or aluminum as the conductor, with an outer thermoplastic PVC insulation layer and a nylon sheath for enhanced abrasion resistance, water resistance, and oil resistance.

THHN wire is a standard cable type commonly used in building electrical systems, often employed in conduit wiring systems such as power distribution lines in residential, commercial, and industrial buildings.