Tariff monitor · Electrical & Wiring

Transformers and power supplies: statutory & effective tariff rates

Statutory HTS duty rates for 22 transformers and power supplies tariff lines (MFN Free–6.6%), from USITC. Effective rate May 2026: 12.41%; monthly history since 2020

Statutory rates from the schedule

  • Transformers, static converters, inverters, and power supplies. This family covers HTS heading 8504: 22 eight-digit rate lines with MFN (column 1, general) rates of Free–6.6% in the 2026 schedule.
  • Chapter 99 flags on individual lines mark Section 301/232 overlay provisions (e.g. 9903.88.15) that apply on top of the MFN column.

What importers actually paid

  • Latest month on record (2026-05): 12.41% effective on $3.1B of imports, versus 11.48% in the same month a year earlier. The monthly archive holds 77 observations from 2020-01 through 2026-05.
  • In 2025, U.S. imports for consumption in this family totaled $31.8B in customs value and paid $3.7B in calculated duties: an effective tariff rate of 11.52%. The effective rate captures Section 301/232 overlays, exclusions, and special-program use that the statutory column cannot.
  • A year earlier the effective rate was 3.07%, so the duty burden 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%).

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%

About this data

  • Reference statistics derived from USITC published data. Not a customs ruling; verify rates with a licensed customs broker before relying on them.

Last reviewed 2026-05-12.