What is the U.S. tariff rate on transformers and power supplies?

USITC calculated duties imply an effective rate of 12.56% in Jun 2026 (calculated duties ÷ covered customs value, USITC DataWeb). The parseable Column 1 General line-rate range is 0%–6.6%; individual lines are called “Free” only when the official General field is literally Free, and product, origin, preference and tariff mix can contribute to the observed-rate difference.

What are the statutory MFN line rates for transformers and power supplies?

The parseable Column 1 General line-rate range is 0%–6.6% across the family's 22 eight-digit HTS lines in the 2026 Harmonized Tariff Schedule (headings 8504). “Free” means the official General field is literally Free for a line; it does not determine final entry liability.

Which countries supply the most transformers and power supplies to the U.S.?

Top retained sources in 2025: Mexico ($6.2B at 2.89%), Thailand ($3.2B at 10.53%), China ($3.0B at 47.11%). Mexico holds 19.5% of total family import customs value. Retained sources cover 76%; their HHI is 780, a lower bound whose floor falls in the diversified range without classifying the omitted tail.

How much transformers and power supplies does the U.S. import?

$31.8B of customs value in 2025, with $3.7B in USITC Calculated Duties — an effective calculated-duty rate of 11.52%.

Is the U.S. a net importer of transformers and power supplies?

Yes — a net importer in 2025: $31.8B imported vs $3.7B exported (exports are 12% of imports).

Tariff monitor · Electrical & Wiring

Transformers and Power Supplies: Statutory & Effective Tariff Rates

USITC Column 1 General rates for 22 transformers and power supplies HTS lines (parseable range 0%–6.6%). Effective rate Jun 2026: 12.56%; monthly history since 2020.

The short answer

The observed effective calculated-duty rate on U.S. imports of transformers and power supplies was 12.56% in Jun 2026, up from 10.7% a year earlier — USITC Calculated Duties divided by covered customs value. The Column 1 General line-rate range is 0%–6.6% across 22 HTS lines in the 2026 schedule; individual lines are called “Free” only when the official General field is literally Free, which still does not determine a shipment’s final duty. Mexico is the largest source, holding 19.5% of 2025 imports.

Statutory rates from the schedule

Transformers, static converters, inverters, and power supplies. This family covers HTS heading 8504: 22 eight-digit rate lines with a parseable Column 1 General range of 0%–6.6% in the 2026 schedule. “Free” means the official General field is literally Free for that line; it does not determine final entry liability.

Observed calculated-duty data

Latest month on record (2026-06): 12.56% effective on $3.2B of imports, versus 10.7% in the same month a year earlier. The monthly archive holds 78 observations from 2020-01 through 2026-06.
In 2025, U.S. imports for consumption in this family totaled $31.8B in customs value, with $3.7B in USITC reported calculated duty on $31.8B of covered customs value: an effective calculated-duty rate of 11.52%. The aggregate reflects the recorded entry mix but does not attribute the result to a specific legal provision.
A year earlier the effective calculated-duty rate was 3.07%, so the observed rate rose 8.4 points.
Top source countries in 2025: Mexico ($6.2B at 2.89%), Thailand ($3.2B at 10.53%), China ($3.0B at 47.11%), South Korea ($2.2B at 6.37%), Taiwan ($2.1B at 11.14%).
Reported freight and insurance equaled 3.11% of covered customs value in 2025 ($751.4M total); charge coverage was 76% of customs value, from USITC DataWeb. It is shown alongside the effective calculated-duty rate and is not part of the customs-value duty base.
For scale, 2025 imports in this family equal 15.7% of the U.S. electrical equipment and appliances industry's $202B gross output (2025, BEA).

Representative rate lines

8504.10.00.00: Ballasts for discharge lamps or tubes · MFN 3%
8504.21.00: Having a power handling capacity not exceeding 650 kVA · MFN Free
8504.22.00: Having a power handling capacity exceeding 650 kVA but not exceeding 10,000 k · MFN Free
8504.23.00: Having a power handling capacity exceeding 10,000 kVA · MFN 1.6%
8504.31.20.00: Unrated · MFN Free
8504.31.40: Having a power handling capacity less than 1 kVA · MFN 6.6%
8504.31.60.00: Having a power handling capacity of 1 kVA · MFN 1.6%
8504.32.00.00: Having a power handling capacity exceeding 1 kVA but not exceeding 16 kVA</il · MFN 2.4%

Frequently asked questions

What is the U.S. tariff rate on transformers and power supplies? USITC calculated duties imply an effective rate of 12.56% in Jun 2026 (calculated duties ÷ covered customs value, USITC DataWeb). The parseable Column 1 General line-rate range is 0%–6.6%; individual lines are called “Free” only when the official General field is literally Free, and product, origin, preference and tariff mix can contribute to the observed-rate difference.
What are the statutory MFN line rates for transformers and power supplies? The parseable Column 1 General line-rate range is 0%–6.6% across the family's 22 eight-digit HTS lines in the 2026 Harmonized Tariff Schedule (headings 8504). “Free” means the official General field is literally Free for a line; it does not determine final entry liability.
Which countries supply the most transformers and power supplies to the U.S.? Top retained sources in 2025: Mexico ($6.2B at 2.89%), Thailand ($3.2B at 10.53%), China ($3.0B at 47.11%). Mexico holds 19.5% of total family import customs value. Retained sources cover 76%; their HHI is 780, a lower bound whose floor falls in the diversified range without classifying the omitted tail.
How much transformers and power supplies does the U.S. import? $31.8B of customs value in 2025, with $3.7B in USITC Calculated Duties — an effective calculated-duty rate of 11.52%.
Is the U.S. a net importer of transformers and power supplies? Yes — a net importer in 2025: $31.8B imported vs $3.7B exported (exports are 12% of imports).

About this data

Reference statistics derived from USITC published data. Not a customs ruling. MFN-Free and Special-rate fields describe statutory line coverage only; final entry liability requires origin, date, eligibility, exclusions and other transaction facts. Calculated Duties are statistical estimates, not a cash-collections ledger. Confirm classification, origin, program eligibility, and final entry liability with a licensed customs broker.

Last reviewed 2026-08-31.