Sourcing dissolved oxygen meters from China

Duty and classification for dissolved oxygen meters

Read from the UK Trade Tariff on 16 October 2026, the relevant heading 9027 lines carried 0% duty for goods from China, with no listed anti-dumping or countervailing duties and no suspensions. The heading covers physical and chemical analysis instruments and their parts. The table gives classification candidates, rather than a confirmed code for every dissolved oxygen meter.

The supplied tariff attaches an export control of mercury to 9027 89 90 00. It is labelled as an export control; ask your customs broker to confirm its relevance and any requirement for the actual goods. No controls are listed against the other table codes in the supplied snapshot.

Give your broker the sensing principle, measured parameters, technical description and details of separately supplied probes before confirming the commodity code. Optical sensing and combined water-analysis functions can affect the classification assessment. See the pH meters guide for the wider heading.

Specify the probe and its compliance documents

Specify optical or electrochemical sensing, portable or bench use, measurement range, accuracy, response time and temperature compensation. Agree how salinity and atmospheric pressure are handled, the cable length, connector, immersion conditions and data export format. List replacement optical caps, membranes and electrolyte where applicable, and obtain the calibration and storage procedure for the supplied probe.

For apparatus within the electromagnetic compatibility rules, the importer must retain the declaration of conformity and technical documentation for 10 years after placement on the Great Britain market. For equipment within the hazardous-substance restriction rules, the importer must be able to evidence compliance when requested by the product safety regulator. Match the documents to the ordered meter, probe and supplied power unit.

The electrical equipment safety rules cover equipment designed or adapted for 50 to 1,000 volts alternating current or 75 to 1,500 volts direct current. Assess the meter and any mains adaptor separately. Importing electrical equipment commercially for UK resale also brings producer-registration responsibilities; producers must register annually. Arrange testing and certification around the actual configuration.

Worked duty example

Illustrative example, not a quote: Illustrative small-business batch of electrochemical dissolved oxygen meters with probes under 9027 89 90 00, invoiced at £10,000 free on board, with £900 of freight and insurance to the UK. The customs value is £10,900. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £10,900, so it is £2,180. 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

Probe identity: check the sensor type, connector, cable and replacement consumables against the approved sample and packing list.

Measurement: follow the agreed calibration procedure, compare readings with a reference instrument and record water temperature, salinity settings and stabilisation behaviour.

Wet operation: inspect seals and cable entries, then test under the agreed immersion conditions; check for unstable readings after movement or temperature changes.

Delivery: check the meter and probe identifiers, power unit, instructions, calibration records and consumables; repeat functional checks on arrival. Use the quality inspection guide to plan the checks.

What goes wrong

A display that powers up does not establish measurement accuracy. Damaged membranes, trapped bubbles, worn optical caps, incorrect compensation settings or an unsuitable calibration procedure can produce misleading readings. Agree acceptance criteria and record the test conditions so the factory and buyer can reproduce disputed results.

Replacement probes may fit the connector but require different firmware or calibration data. Confirm compatibility and storage instructions before ordering spares. A report for another meter or adaptor leaves the supplied configuration unassessed; reconcile model identifiers before shipment.

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.