In Detail
The "parts of parts" question arises when a component is a part of a recognized part of a finished article. Courts and CBP have held that the phrase "parts of [article]" in a heading can extend to components of those parts, provided the chain of part relationships is traceable back to the original article. A clutch assembly is a part of a motor vehicle; clutch plates are parts of the clutch assembly; clutch plates may therefore be classified as parts of motor vehicles.
The chain is not infinite. A component sufficiently removed from the original article — particularly one with general commercial uses not specific to the article — may not qualify as a "part" of the original article at the end of the chain. The further removed the component, the more carefully CBP examines whether it retains dedication to the original article.
The parts-of-parts analysis must also account for the specificity requirement: if a heading describes the component in its own right — regardless of its position in the parts chain — that specific heading governs. A bearing is described in heading 8482; it is not classified as a "part of a motor vehicle" even if it is used exclusively in clutch assemblies used exclusively in motor vehicles.
Parts-of-parts issues arise most frequently in machinery, vehicles, aerospace equipment, and electronics, where complex assemblies are themselves classified as parts and their sub-components are imported separately.
Classification Significance
Incorrect parts-of-parts classifications produce cascading duty and trade remedy errors. If a component is classified as a 'part of a machine' when a specific heading applies, the entry carries the wrong code and rate. If a component is not recognized as a part-of-a-part when it qualifies, it may be classified in a less specific residual heading, also producing an incorrect rate.
How Kanon Handles This
Kanon traces parts relationships through its product attribute model when classifying components. When a product is described as a component of a recognized part, Kanon applies the parts-of-parts analysis — evaluating the chain, the specificity of any applicable heading for the component itself, and whether the component retains sufficient dedication to the original article. The analysis is documented in the Classification Support Package.
Frequently Asked Questions
Does the 'parts of parts' principle apply to all chapters?
It applies generally where 'parts' provisions exist, but is most developed in Chapters 84, 85, 87, and 88. The specificity analysis must still be performed regardless of chapter.
How far down the parts chain does the principle extend?
Courts have not drawn a precise limit. The further removed the component, the more important it is that the component is specifically designed for and dedicated to the original article with no broader commercial use.