8406.81 - Of an output exceeding 40 MW:

This HTS category, 8406.81, encompasses steam turbines and other vapor turbines that generate an output exceeding 40 megawatts (MW). These are high-capacity prime movers, typically employed in large-scale industrial power generation, such as in central power stations for electricity production or in heavy manufacturing facilities requiring substantial mechanical power. The defining characteristic of turbines within this classification is their significant power output capability.

Distinction from sibling categories is crucial for accurate classification. Specifically, this node, 8406.81, is differentiated from its sibling, 8406.82, by the power output threshold. While 8406.81 covers turbines with an output *exceeding* 40 MW, 8406.82 pertains to those with an output *not exceeding* 40 MW. This quantitative metric serves as the primary criterion for distinguishing between these two categories.

Within the 8406.81 classification, further subdivisions exist to refine the classification of these powerful turbines. Subcategory 8406.81.10 specifically covers steam turbines, which are the most common type of large-scale vapor turbine used for power generation. The residual category, 8406.81.90.00, accounts for any other types of vapor turbines that meet the exceeding 40 MW output requirement but are not specifically steam-driven.