Sourcing Gyrotron Tubes from China
Gyrotron tubes and relevant tube parts from China carry a flat 0% UK duty in the supplied tariff data. Confirm classification and match the tube to the intended equipment. Hazardous-substance compliance depends on whether it is a business component or finished equipment. Cambridge China Bridge sources gyrotron tubes.
Gyrotron tube duty and classification
Read from the UK Trade Tariff on 2 October 2026, heading 8540 covers thermionic, cold cathode and photocathode valves and tubes. For a gyrotron tube, the other microwave tubes line, 8540 79 00 90, is the classification to check. The table distinguishes buying variants under that same line. Separately supplied tube parts may fit 8540 99 00 90, subject to their identity.
The supplied extract records 0% duty for goods from China on both lines, with no anti-dumping or countervailing measures, suspensions or attached import controls. Import VAT is normally 20%; see UK import duty and VAT. These tariff entries do not establish the finished equipment's product compliance.
Give your customs broker the tube datasheet, function, drawings and a clear description of any separately supplied parts to confirm the commodity code. For the wider heading, see vacuum tubes and magnetrons.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Continuous-wave gyrotron tubes | 8540 79 00 90 | 0% | None |
| Other valve and tube parts, subject to classification | 8540 99 00 90 | 0% | None |
Specify the gyrotron and its installation interfaces
Specify operating frequency, output power, continuous or pulsed operation, pulse duration and duty cycle where applicable. Record the required output mode, window arrangement, mounting dimensions and output connection. Agree beam voltage and current, heater supply, magnetic-field requirements and cooling conditions with the equipment engineer. State whether the order includes only the tube or also its magnet, power supply and controls.
Ask for test records tied to the tube's serial number, showing the operating conditions used to demonstrate output. Agree acceptance criteria for vacuum integrity, cooling connections and output stability. Require handling instructions and packing that supports the tube without loading its output window or connectors.
Official guidance says component parts sold on a business-to-business basis are outside the hazardous-substance regulations' scope. For a tube incorporated into covered finished equipment, obtain material declarations and any exemption justification to support the final assembly's compliance. Employers must control workplace risks; agree a controlled commissioning procedure with the installation engineer, including checks for microwave leakage, high voltage and magnetic fields.
Worked duty example
Illustrative example, not a quote: A replacement gyrotron tube for an existing installation, illustrative only under 8540 79 00 90, invoiced at £30,000 free on board, with £900 of freight and insurance to the UK. The customs value is £30,900. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £30,900, so it is £6,180. With no duty, the only import tax is the VAT, which a VAT-registered importer can usually reclaim. The import duty and VAT guide explains each step.
Inspection checklist
Identity: match the model, serial number, drawings and test records to the ordered tube; check whether it is new or refurbished as agreed.
Interfaces: check mounting points, output window, electrical connectors and cooling connections against the approved drawings before installation.
Condition: inspect for window damage, bent connections, loose fittings and signs of transit shock; photograph the tube and its supports before unpacking fully.
Performance: have the equipment engineer verify output and stability under the agreed cooling, magnetic-field and electrical conditions. Record results against the serial number; see quality inspection.
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What goes wrong
A tube can match the advertised frequency yet fail to suit the installation because its output mode, window, mounting, cooling or magnetic-field requirements differ. A pulsed output claim also does not demonstrate continuous operation. Compare the complete operating specification and ask for test conditions rather than accepting a headline power claim.
Transit damage can affect the output window or vacuum integrity without obvious damage to the outer crate. Missing serial-specific records make acceptance harder. Agree packing, inspection and commissioning responsibilities before dispatch, and hold damaged goods for assessment before energising them.
Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For components and parts, see sourcing for manufacturers.
Frequently asked questions
What is the UK import duty on gyrotron tubes from China?
The supplied tariff extract records 0% on other microwave tubes under 8540 79 00 90 and other tube parts under 8540 99 00 90, with no trade remedies. Confirm the classification of the actual goods.
Does a gyrotron tube need its own hazardous-substance declaration?
Official guidance excludes business-to-business component parts from scope. Ask for material evidence to support compliance when the tube is incorporated into covered finished equipment.
What should I specify when ordering a replacement gyrotron?
Specify frequency, output, continuous or pulsed operation, output mode, window, mounting, electrical supplies, magnetic-field requirements and cooling. Check these against the existing installation.
Can I accept a gyrotron using the factory test report?
Use serial-specific factory records to check the agreed operating conditions. Also agree arrival inspection and commissioning tests with the equipment engineer before placing the order.