Steel wind turbine tower sections are generally classified under 730820 as towers or lattice masts of iron or steel. Importers should confirm that the article is the structural tower itself rather than a mechanical component of the turbine, which could route to a different chapter.

Prefabricated buildings—complete or substantially complete structures designed to be assembled on site as habitable or functional enclosures—fall under heading 9406. Heading 7308 covers structural components, frames, and assemblies that are parts of a structure rather than a complete building unit. A steel frame kit that constitutes a complete building shell is more likely to route to 9406; individual beams, columns, and connection plates stay in 7308.