In regards to conductor sizes, what do the term 'THWN' indicate?

The term 'THWN' stands for Thermoplastic Heat and Water Resistant Nylon, which describes a specific type of insulation used on electrical conductors. This designation indicates that the wire can handle high temperatures (up to 90°C, or 194°F) and is resistant to moisture, making it suitable for both wet and dry locations. The thermoplastic material allows the wire to be more flexible and easier to handle compared to thermoset insulation.

The nylon aspect of THWN insulation provides additional protection against abrasion and mechanical damage, enhancing the durability of the wire in various applications. This combination of characteristics makes THWN conductors optimal for use in locations where exposure to water is a concern, as well as in higher temperature environments.

Understanding this terminology is essential for selecting the appropriate wire for specific installations, as it ensures compliance with safety standards and contributes to the longevity and efficiency of electrical systems.