The duty stack for power and connectivity hardware, by HTS code

Verified 21 September 2026: a charger or adapter of Chinese origin under HTS 8504.40.85 pays an effective 37.5% in duties; the same article of Vietnamese origin pays 12.5%; from Mexico under USMCA it pays 0.0%. The table below shows every layer and the authority that created it. The layers add — each is ad valorem on the entered value, not compounded on the layer before it.

The connectivity side no longer runs on the same stack. Since 6 April 2026, connectorized cable is an article of copper and carries a fourth layer — a 25% Section 232 duty that power products do not pay and that USMCA does not waive. That section is below, and it is the part of this page most likely to be different from what your broker quoted you last year.

The full stack, layer by layer

This is the reference for HTS 8504.40.85 — switching power adapters and chargers, the most common power SKU. Rates are current as of the verification date at the top of this page.

The China − Vietnam delta is 25.0 points — the List 3 Section 301 layer, which applies to Chinese origin only; both origins carry the 12.5% forced-labor duty. Mexico assumes USMCA qualification with a valid certificate of origin; USMCA-originating goods are exempt from both Section 301 duties. Transshipped goods misdeclared as Vietnamese are assessed the full Chinese-origin rate with every layer reinstated, plus penalties. Which is why the 25-point delta is only worth as much as the origin behind it: Kestner builds the same part in its own plants in both China and Vietnam, so you can elect the country of origin per order and have it documented per unit — real production, not a relabel.

Connectivity — cable assemblies by HTS code

Cable no longer runs on the power stack. Four connectorized lines — 8544.42.10, 8544.42.20, 8544.42.90 and 8544.49.10 — are listed as articles of copper in HTSUS U.S. note 16(c)(viii), and since 6 April 2026 they carry a 25% Section 232 copper duty on the full customs value under Chapter 99 heading 9903.82.09. Two consequences follow, and they run in opposite directions:

1. The copper duty applies from every origin — including USMCA-originating Mexico. HTSUS note 16(b) is explicit: for goods eligible for free-trade treatment, the Section 232 duty “shall be collected in addition to any special rate of duty otherwise applicable.” A Mexican-origin patch cord is no longer a 0% entry.
2. It replaces the forced-labor duty rather than stacking with it. U.S. note 52(f)(1) excludes articles of copper provided for in 9903.82.09 from the 12.5% Section 301 forced-labor duty. The net move on a Chinese-origin assembly is +12.5 points, not +25.

Everything else in the category is untouched. Coax, optical fiber, and bulk unterminated cable appear on no Section 232 metals list, so they keep the forced-labor layer and pay no copper duty:

The copper duty is not automatic. Note 16(c) reaches the article only where the applicable metal is at least 15% of the weight of the imported good, and where a code sits on more than one note-16 list the listed metals are aggregated — 8544.42.90 is also on the derivative-aluminium list, so copper and aluminium count together. A normal cable assembly clears this comfortably; the conductor is the heaviest thing in it. An assembly that does not — a short lead dominated by moulded plastic and a die-cast shell — falls to 9903.82.03 instead: no copper duty, but the 12.5% forced-labor duty comes back, for 40.1% from China and 15.1% from Vietnam. Weigh the copper before you plan against either figure.

Two classification moves that used to save money now cost it. Telecom-grade connectorized cable can enter Free under 8544.42.20 and modular-telephone-terminated cable under 8544.42.10 — but both lines are on the same copper list, so the move saves the 2.6-point base and nothing more. And bulk (unterminated) Ethernet cable on spools is not the connectorized code: CBP’s current position — ruling N354596, October 2025 — places standard bulk Cat5e/6 under 8544.49.30 at a 5.3% base, because the Free ≤80 V telecom line (8544.49.10) is decided by the cable’s maximum voltage rating, and ordinary LAN jacket is rated 300 V. Since April that ruling is a favour: 8544.49.10 is on the copper list and 8544.49.30 is not, so the Free line would cost 25 points of copper duty to save 5.3 points of base.

The List 3 Section 301 (Chapter 99 heading 9903.88.03) adds its 25% on Chinese origin across all of these lines, unchanged — HTSUS note 16(b) preserves it alongside Section 232. The cable analysis, with the same origin logic, is on USB-C and cable assembly tariffs.

Other power codes we enter

The adjacent power code carries the same Free base rate and the same three layers, so its effective rates match 8504.40.85.

MFN base rate: 8504.40.95 (“Other” static converters) is Free — the same base as 8504.40.85 — then 25% Section 301 on Chinese origin and the 12.5% Section 301 forced-labor duty on both origins ex-USMCA.

How to read this if you buy from China today

On a $100,000 entry of 8504.40.85, origin China costs $37,500 in duty; origin Vietnam costs $12,500. The delta is $25,000 — roughly the gross margin on the goods themselves. This is why origin, not unit price, is the number to negotiate first. Estimate your own per-unit figure with the landed-cost calculator.

The delta only survives scrutiny if the origin does. A quote that beats this table by relabeling will cost the full Chinese-origin rate plus penalties when CBP samples the entry. Ask any supplier — including us — for the documents listed on the Sourcing page, and see how to verify a Vietnam country of origin before you re-source. Not sure which code your part enters under? Start with the HTS code & duty finder.

Cite this data

This page and its machine-readable copy are maintained from a single dataset, so the two cannot disagree. Cite as: Kestner Supply, “The duty stack for power and connectivity hardware,” verified 2026-09-21 — kestnersupply.com/insights/duty-stack-power-products. A machine-readable JSON version — every code, layer, effective rate, and citation — is at /data/duty-stack.json (CC BY 4.0; attribution required).