HSChapter 85
U.S. imports of parts for electrical transformers, static converters & inductors (HS 850490) totaled $348.6M in April 2026, traded with 64 countries.
Importers of Parts for Electrical Transformers, Static Converters & Inductors paid $39.8M in duties in April 2026 — an effective duty rate of 16% on $245.6M in dutiable value, based on actual customs collections rather than the published tariff schedule. Parts for Electrical Transformers, Static Converters & Inductors imports of $348.6M in April 2026 ran 10% below the year-to-date monthly average of $389.0M.
Last updated: April 2026 dataTransformer and converter parts span a wide material spectrum — from grain-oriented silicon steel laminations and stacked cores (8504909634, 8504909638) to ferrite cores (8504909610, 8504909630) and printed circuit assemblies for ADP power supplies (8504902000) — making correct classification among the 14 active 10-digit lines a recurring challenge. Mexico leads US import supply, followed by Thailand and Canada, reflecting deep North American and Southeast Asian electronics supply chains. Ferrite and lamination components are particularly sensitive to Section 301 tariffs when sourced from China, and misclassification between transformer parts and static converter or inductor parts can trigger reclassification audits. Importers should maintain detailed bills of materials and engineering drawings to substantiate the specific part-type claimed.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
The US schedule distinguishes laminations for incorporation into stacked cores (8504909634), stacked cores for incorporation into transformer parts (8504909638), and wound cores for incorporation into transformers (8504909642). Classification depends on the core's construction method and its stage of manufacture. Engineering drawings and supplier declarations confirming whether the core is wound or stacked are essential supporting documents.
Yes. The schedule separates printed circuit assemblies of power supplies for ADP machines (8504902000) from PCAs of other 850440 or 850450 articles (8504906500) and general NESOI PCAs (8504907500). The ADP-specific line requires that the assembly be dedicated to a power supply designed for ADP equipment of heading 8471. Importers should retain end-use documentation and OEM specifications to support the claimed line.
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Monthly import values over time
HS10 import codes under this HS6 parent. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Duty Collected |
|---|---|---|---|---|
| 8504907500 | PRINTED CIRCUIT ASSEMBLIES PARTS; NESOI | $99.7M | 14.65% | $4.5M |
| 8504909650 | STATIC CONVERTER PARTS, NESOI | $69.6M | 15.93% | $10.4M |
| 8504909690 | INDUCTOR PARTS, NESOI | $36.6M | 17.77% | $5.4M |
| 8504904100 | POWER SUPPLY PARTS FOR ADP MACHINES, NESOI | $32.7M | 15.05% | $4.5M |
| 8504909646 | TRANSFORMER PARTS, NESOI | $32.0M | 11.40% | $2.3M |
| 8504909642 | WOUND CORES PARTS FOR INCORP INTO TRANSFORMERS | $28.8M | 17.15% | $4.5M |
| 8504909634 | LAMINATIONS FOR INCORP IN STACKD CORES, TRANS PRTS | $9.9M | 19.02% | $1.7M |
| 8504906500 | PRINTED CIRCUIT ASSEMBLY PARTS OF 850440 OR 850450 | $9.3M | 16.88% | $1.1M |
| 8504902000 | PRINTED CIRCUIT ASSEMB OF PWR SUPS FOR ADP MACHINE | $9.0M | 21.73% | $1.5M |
| 8504909638 | STACKED CORES FOR INCORP INTO TRANSFORMER PARTS | $8.8M | 21.92% | $1.9M |
| 8504909630 | FERRITES, NESOI | $6.6M | 13.39% | $854K |
| 8504909610 | FERRITES FOR TRANSFORMERS | $5.6M | 22.27% | $1.1M |
PRINTED CIRCUIT ASSEMBLIES PARTS; NESOI
STATIC CONVERTER PARTS, NESOI
INDUCTOR PARTS, NESOI
POWER SUPPLY PARTS FOR ADP MACHINES, NESOI
TRANSFORMER PARTS, NESOI
WOUND CORES PARTS FOR INCORP INTO TRANSFORMERS
LAMINATIONS FOR INCORP IN STACKD CORES, TRANS PRTS
PRINTED CIRCUIT ASSEMBLY PARTS OF 850440 OR 850450
PRINTED CIRCUIT ASSEMB OF PWR SUPS FOR ADP MACHINE
STACKED CORES FOR INCORP INTO TRANSFORMER PARTS
FERRITES, NESOI
FERRITES FOR TRANSFORMERS
HS10 export codes under this HS6 parent. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 8504900080 | STATIC CONVERTER & INDUCTOR PARTS, NESOI | $54.0M |
| 8504900020 | TRANSFORMER PARTS | $6.2M |
STATIC CONVERTER & INDUCTOR PARTS, NESOI
4.3M no
TRANSFORMER PARTS
10.9M no
STATIC CONVERTERS; ADP POWER SUPPLIES
HS 850440
| State | Imports | Exports | Balance |
|---|---|---|---|
| California | $78.2M | $5.9M | -$72.3M |
| Texas | $57.6M | $7.9M | -$49.7M |
| Virginia | $19.9M | $6.3M | -$13.6M |
| Port | Imports | Exports | Balance |
|---|---|---|---|
| LAREDO, TX | $55.9M | $6.0M | -$49.9M |
| LOS ANGELES, CA | $45.1M | -- | -$45.1M |
| OAKLAND, CA | $34.8M | -- | -$34.8M |