Sourcing capacitor-ferrite filters from China

UK duty and classification

Read from the UK Trade Tariff on 15 November 2026, heading 8548 covers electrical parts of machinery or apparatus not specified elsewhere in the chapter. Every supplied line carries 0% duty for goods from China, with no listed anti-dumping or countervailing duty and no listed suspensions. The table shows purchasing formats sharing the residual electrical-parts line, subject to classification confirmation.

The tariff attaches import and export waste controls to the residual line and the specified power-line filter line. For waste shipped under notification controls, consent from the authorities of dispatch, destination and transit is needed before shipment. If buying scrap, rejected stock or recovered filters from China, confirm the waste status and applicable requirements with your customs broker before shipping.

Code 8548 00 90 45 describes a power-line filter with a tightly defined specification. Use it only when the complete description matches. Consider 8548 00 90 99 for other filters only after checking more specific headings. Send the circuit, drawing, ratings and intended use to your broker; see finding your commodity code and the wider electrical-parts guide.

Specify the capacitor, ferrite and mounting

Specify the internal filter circuit, capacitance and tolerance, dielectric material, ferrite material, rated voltage and current, conductor resistance and operating temperature range. Agree attenuation curves with the frequency range, source and load impedance, fixture and current bias recorded. Ask for results on the offered part number rather than a similar catalogue model.

Define the mounting thread or hole, panel thickness, conductor dimensions, plating, earthing contact, installation torque and permitted soldering process. For components sold between businesses, official GB guidance places component parts outside direct RoHS scope. Ask the relevant authority to confirm the substance restrictions applicable to the finished electrical product. Request part-specific material declarations and supporting data for the ceramic, solder, plating and encapsulant.

Worked duty example

Illustrative example, not a quote: Illustrative order only: 250 capacitor-ferrite feedthrough filters, subject to classification under 8548 00 90 99, invoiced at £1,200 free on board, with £600 of freight and insurance to the UK. The customs value is £1,800. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £1,800, so it is £360. 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 and fit: match part numbers and batch labels to the approved drawing; check threads, panel seating, conductor alignment and mounting hardware.

Electrical checks: measure capacitance, conductor resistance and insulation resistance; perform dielectric testing using the agreed method and acceptance criteria.

Filter performance: compare attenuation with the approved sample using the agreed fixture, impedance and current bias; check heating under the intended load.

Condition and packing: inspect ceramic bodies, ferrites, seals and plating for cracks or damage; check that packing protects pins and mounting surfaces. See quality inspection explained.

What goes wrong

A changed ferrite material or capacitor can leave the filter looking identical while changing attenuation. Catalogue curves measured under different impedances or without current bias may not represent your installation. Agree the circuit and test conditions, retain an approved sample and require approval before material substitutions.

Poor contact between the filter body and enclosure can weaken filtering. Installation stress can crack the ceramic, while soldering heat can damage the assembly. Trial the actual panel and assembly process before approving production, then compare arrival samples with the agreed electrical and mechanical checks.

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.