Sourcing PTC thermistors from China
PTC thermistors classified under heading 8533 carry 0% UK duty from China across the listed lines. The main compliance rule is to distinguish business-to-business components from finished equipment: the final assembly must meet applicable hazardous-substance rules. Cambridge China Bridge sources PTC thermistors.
Duty and classification for PTC thermistors
Read from the UK Trade Tariff on 30 September 2026, heading 8533 covers electrical resistors, including rheostats and potentiometers, other than heating resistors. For PTC thermistors, establish the function, construction and power handling capacity before choosing the commodity line. A component sold as a heating resistor needs separate classification.
Every line in the supplied heading data carries 0% duty for goods from China. No anti-dumping or countervailing duty, suspension or attached import control is recorded. The table gives classification candidates, not interchangeable codes: the fixed-resistor rows apply only where that classification is confirmed.
Send the datasheet, resistance-temperature curve and intended application to your customs broker and confirm the commodity code. For the wider thermistor buying context, see the NTC thermistor guide.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Other variable resistors, including PTC candidates, up to 20 W | 8533 40 10 00 | 0% | None |
| Other variable resistors, including PTC candidates, over 20 W | 8533 40 90 00 | 0% | None |
| Other fixed resistors up to 20 W, only if fixed-resistor classification applies | 8533 21 00 00 | 0% | None |
| Other fixed resistors over 20 W, only if fixed-resistor classification applies | 8533 29 00 00 | 0% | None |
Specify the PTC behaviour, not just the resistance
State whether you need ceramic temperature sensing or switching behaviour, or a polymer resettable protection component. Specify resistance and tolerance at an agreed reference temperature, the resistance-temperature curve, switching temperature where relevant, rated voltage, operating temperature range, package, lead spacing and mounting method.
For resettable protection parts, agree hold current, trip current, trip behaviour at the intended ambient temperature and resistance after recovery. Approve samples in the actual circuit and record the cooling and reset conditions. A matching package and initial resistance do not establish equivalent protection.
Official GB guidance excludes component parts sold business to business from the hazardous-substance regulations themselves, but requires the final marketed assembly, including its components, to comply. Request part-specific material declarations and supporting reports for the finished-product assessment.
Worked duty example
Illustrative example, not a quote: Illustrative order: 10,000 PTC thermistors, subject to confirmation of classification under 8533 40 10 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
Identity: match the manufacturer, full part number, package, lead spacing and lot labels against the approved sample and purchase specification.
Resistance curve: measure samples at the agreed temperatures using a controlled method that limits self-heating; compare the results with the approved curve and tolerance.
Switching and recovery: check switching or trip behaviour in the agreed test circuit, then check recovery resistance after the specified cooling conditions.
Condition and records: inspect ceramic bodies, coatings, leads and packing for damage; match material declarations and test records to the supplied part numbers and lots.
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What goes wrong
A substitute can match room-temperature resistance yet switch at a different temperature or trip differently in a warm enclosure. Testing with excessive measurement current can also heat the component and disguise its true resistance. Agree the test method before comparing factory results with arrival checks.
Reject unexplained changes to material, package or part number. Keep approved samples and lot records so that failures can be traced to the shipment concerned. Use the quality inspection guide to turn these checks into an inspection brief.
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 PTC thermistors from China?
The supplied tariff data shows 0% on every heading 8533 line, with no recorded anti-dumping or countervailing duty. Confirm that the particular PTC component belongs in this heading.
Which commodity code should I use for PTC thermistors?
Check the function, construction and power handling capacity with your customs broker. The table lists candidates; a heating resistor needs separate classification.
Do business-to-business PTC components need hazardous-substance compliance?
Official GB guidance puts business-to-business component parts outside the regulations themselves. The final marketed assembly, including its components, must comply, so obtain supporting material data.
How do I check a replacement PTC thermistor?
Compare the resistance-temperature curve, switching or trip behaviour, voltage rating, package and recovery resistance. Test the replacement in the intended circuit rather than relying on initial resistance alone.