North American Industry Classification System
U.S. imports of Power, Distribution & Specialty Transformers (NAICS 335311) totaled $880.7M in August 2026, imported from 75 countries.
Importers of Power, Distribution & Specialty Transformers paid $143.0M in duties in August 2026, an average duty rate of 16.25% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: August 2026 dataVoltage transformation equipment — from small distribution units to large power transformers serving utility grids — occupies a strategically sensitive position in US energy infrastructure, and the Department of Energy has issued procurement restrictions on certain foreign-sourced bulk-power system transformers. Section 301 tariffs apply to many transformer components and finished units imported from China, adding cost pressure to a product category already characterized by long lead times and custom engineering. Classification under this NAICS code spans a wide range of kVA ratings and design types, each of which may map to a different HTS heading with distinct duty treatment. Domestic manufacturing capacity for large power transformers is limited, making import sourcing decisions consequential for grid reliability planning.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
13.3K import shipments a month
The Department of Energy has authority under Executive Order 13920 to restrict acquisition of bulk-power system electric equipment — including large power transformers — from suppliers with ties to foreign adversaries. Importers of grid-scale transformers must assess whether their supplier and equipment fall within the scope of these restrictions, which are separate from standard customs tariff requirements.
HTS headings for transformers are subdivided by power-handling capacity (kVA or MVA ratings), with different subheadings and duty rates applying at various thresholds. A transformer that falls just above or below a rating breakpoint can land in a materially different tariff category, so precise technical specifications must be confirmed before filing an entry.
National industry 3 of 4 in naics industry 33531
National industry 335311 · $880.7M of $6.7B
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Imports · August 2026
origin
Mexico and South Korea together supply 50% of it. China pays 39.8% duty; Brazil 11.9%.
customs district
Census does not publish district detail for this classification system.
destination
Census publishes state breakdowns for NAICS to the 4-digit level only. See NAICS 3353 for those.
entry
Census does not publish port detail for this classification system.
ImportsExports
Imports
$880.7MYoY · free account
Exports
$49.8MYoY · free account
12-mo low · imports
Low · free accountOver the twelve months to August 2026, the U.S. imported $10.3B of Power, Distribution & Specialty Transformers and exported $605.6M.
Through August 2026. Source: U.S. Census Bureau.