THHN wire is commonly used in commercial wiring and residential wiring applications. THHN wire is rated to 600V, 90C and has a coated nylon insulation allowing for easy pulling of the wire through conduit. THHN wire is available in various wire gauge sizes, colors and lengths. THHN wire can also be used as MTW wire or THWN wire. Wire can be purchased in small or large quantities. Solid THHN is only available in 14 gauge and 12 gauge wire sizes.