Product classification
HS code for Oil-filled transformer: 8504.22
Electrical transformers, liquid dielectric, having a power handling capacity exceeding 650kVA but not exceeding 10,000kVA.
Classification of oil-filled transformer under HS 8504.22
HS code 8504.22 is utilized for the classification of liquid dielectric transformers with a power handling capacity exceeding 650 kVA but not exceeding 10,000 kVA. This code is part of Chapter 85, which covers electrical machinery and equipment. Heading 8504 specifically addresses electrical transformers, static converters, and inductors. The \"liquid dielectric\" designation refers to transformers where the core and windings are immersed in an insulating liquid, typically mineral oil, which serves both as an electrical insulator and a cooling medium. The sub-classification is strictly based on the rated power handling capacity, measured in kilovolt-amperes (kVA). These units are common in industrial power distribution and medium-voltage substations. The classification is determined by the technical specifications of the transformer at its continuous rated power, rather than its peak or intermittent capacity. Proper classification ensures compliance with energy efficiency standards and electrical safety regulations that vary by power bracket.
- Covers
- Oil-immersed distribution transformers
- Mineral oil-filled power transformers (650kVA-10,000kVA)
- Step-down transformers for industrial substations
- Pad-mounted liquid-filled transformers
- Ground-mounted oil-filled electrical units
- Also under 8504.22
- Siemens power transformers
- ABB liquid-immersed transformers
- GE Prolec medium power transformers
- Hyundai Electric transformers
- Toshiba medium voltage transformers
Codes often confused with 8504.22
Common mistake. The most frequent misclassifications involve the power capacity thresholds. HS code 8504.21 is often incorrectly used for units that actually exceed 650 kVA, while 8504.23 is mistakenly applied to units that do not exceed 10,000 kVA. Furthermore, dry-type transformers (which do not use liquid dielectric) are often confused with oil-filled units; dry-type transformers are classified under subheadings 8504.31 through 8504.34 depending on their kVA rating. It is critical to verify the cooling method (liquid vs. air/resin) and the exact kVA rating on the manufacturer's nameplate to avoid using the wrong code.
Top exporters and importers of HS 850422 (the code used for oil-filled transformer), 2025
In 2025, the largest exporter of HS 850422 (the code used for oil-filled transformer) in UN Comtrade data was China, with 29% of world exports; the largest importer in UN Comtrade data was the United States, with 37% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 850422, not only oil-filled transformer.
Top exporters 2025 · share of world exports
- 1 China $1.9B 29% of world exports
- 2 Mexico $881M 14% of world exports
- 3 South Korea $618M 9.5% of world exports
World total: $6.5B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $2.1B 37% of world imports
- 2 Germany $430M 7.4% of world imports
- 3 Spain $316M 5.4% of world imports
World total: $5.8B Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for oil-filled transformer
Brazil classifies oil-filled transformer under NCM 8504.22.00: HS 8504.22 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about oil-filled transformer
What is the HS code for Oil-filled transformer?
The HS code for Oil-filled transformer is 850422 (Electrical transformers; liquid dielectric, having a power handling capacity exceeding 650kVA but not exceeding 10,000kVA). The HS code for a liquid dielectric (oil-filled) transformer with a capacity between 650 kVA and 10,000 kVA is 8504.22.
How do I classify Oil-filled transformer for customs?
Oil-filled transformer is classified under HS code 850422 — Electrical transformers; liquid dielectric, having a power handling capacity exceeding 650kVA but not exceeding 10,000kVA. This is a 6-digit subheading level code.
How do I distinguish between 8504.22 and 8504.33?
Code 8504.22 is specifically for liquid dielectric transformers, whereas 8504.33 is for other types of transformers (like dry-type) with a capacity between 16 kVA and 500 kVA.
Which countries are the top exporters of oil-filled transformer (HS 850422)?
In 2025, the top exporters of HS 850422 (the code used for oil-filled transformer) in UN Comtrade data were China ($1.9B, 29% of world exports), Mexico ($881M) and South Korea ($618M). World exports came to about $6.5B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of oil-filled transformer (HS 850422)?
In 2025, the top importers of HS 850422 (the code used for oil-filled transformer) in UN Comtrade data were the United States ($2.1B, 37% of world imports), Germany ($430M) and Spain ($316M). World imports came to about $5.8B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Oil-filled transformer the same in all countries?
The base HS code 850422 for Oil-filled transformer is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for oil-filled transformer in Brazil?
In Brazil, oil-filled transformer (HS 850422) is classified under NCM 8504.22.00.