Sourcing current-sense shunts from China

UK duty on current-sense shunt resistors

Read from the UK Trade Tariff on 4 November 2026, heading 8533 covers electrical resistors, including rheostats and potentiometers, other than heating resistors. Current-sense shunts are fixed resistors bought to measure current through a known resistance. The table separates chip and metal-element examples within the same commodity line; it also shows the line for separately supplied resistor parts.

The supplied tariff record shows 0% duty on every line for goods from China, with no anti-dumping or countervailing measures, suspensions or attached import controls. Other fixed resistors with power handling not exceeding 20 W fall under 8533 21 00 00; those above that rating fall under 8533 29 00 00. Import VAT is separate from duty.

Confirm the commodity code using the construction, rated power and description of the goods actually supplied. For the wider heading, see resistors and potentiometers.

Specify the shunt and its measuring conditions

Specify resistance, tolerance, temperature coefficient, continuous power, pulse loading, operating temperature and package dimensions. Name the resistor technology and terminal arrangement, including separate current and sensing connections where required. Agree the resistance measurement method, mounting conditions and thermal derating against the supplier's datasheet.

For bolted shunts, specify terminal material, hole positions, tightening instructions and the sensing connection points. For chip shunts, specify the land pattern, terminal finish and packing. Approve samples in the intended circuit before accepting a substitute part.

For supply into Great Britain, official guidance excludes component parts sold business-to-business from RoHS scope, but requires an in-scope finished assembly to comply, including its components. Ask for part-specific restricted-substance declarations and material data to support the finished-product assessment.

Worked duty example

Illustrative example, not a quote: Illustrative order: 10,000 current-sense shunt resistors; FOB and freight values are illustrative under 8533 21 00 00, invoiced at £9,000 free on board, with £300 of freight and insurance to the UK. The customs value is £9,300. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £9,300, so it is £1,860. 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

Resistance: measure samples from each lot using separate current and sensing connections; compare results with the agreed tolerance and measurement temperature.

Thermal behaviour: test samples under the agreed mounting and load conditions; check temperature rise and resistance drift against the approved datasheet.

Construction: compare dimensions, terminal positions, welds, plating and markings with the drawing and approved sample; inspect for cracks and damaged terminals.

Traceability: match manufacturer labels, part numbers and lot codes to the order, test records and material declarations. Keep the arrival checks with the lot record.

What goes wrong

Lead and contact resistance can distort a low-resistance measurement. Poor sensing-point placement, loose bolted connections and inadequate heat removal can make an acceptable sample perform badly in the circuit. A substituted alloy or package can also change thermal drift or pulse performance.

Agree the test fixture and acceptance conditions before ordering, then compare bulk samples with the approved part. Investigate unexpected drift before releasing the lot to production. Use the inspection guide to define checks with the supplier.

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.