Sourcing partial discharge detectors from China

Duty and classification

Heading 9030 covers instruments for measuring or checking electrical quantities. For partial discharge detectors, distinguish instruments measuring voltage or current from other electrical measuring instruments, and confirm whether they have a recording device. The table gives candidate lines and dedicated parts; it does not classify every detector. A purely acoustic instrument needs a separate classification check.

Read from the UK Trade Tariff on 30 September 2026, all listed lines carried 0% duty for goods from China. The supplied tariff record shows no anti-dumping or countervailing duty, suspensions or attached import controls. Import VAT is normally 20%; zero customs duty does not remove VAT.

Confirm the commodity code using the measurement principle, measured quantity, recording function and supplied accessories. For the wider electrical testing context, see insulation resistance testers.

Specify the sensor method and usable results

State whether the detector uses transient earth voltage, ultrasonic, high-frequency current or ultra-high-frequency sensing. Describe the switchgear, cables or transformers to be inspected, the sensor mounting and whether testing is online or offline. Specify bandwidth, sensitivity, noise rejection, phase reference, recording and report export. Require the supplier to distinguish calibrated apparent-charge measurements from relative signal indications.

For Great Britain, electromagnetic compatibility rules cover electrical equipment liable to generate electromagnetic disturbance, subject to exceptions. Confirm with the relevant authority whether mains-powered instruments fall within the electrical equipment safety rules described in our reference guide; check the supplied power adaptor too. For equipment within those safety rules, importers must ensure instructions are in easily understandable English.

Hazardous-substance rules cover electrical equipment, cables and spare parts unless specifically excluded. Ask for model-specific supporting material evidence. Wireless models are radio equipment, and importers must not place radio equipment on the Great Britain market unless it meets the essential requirements. Establish whether your resale business is an electrical equipment producer; producers must register annually.

Worked duty example

Illustrative example, not a quote: 2 recording partial discharge detector kits for an inspection business (illustrative) under 9030 84 00 00, invoiced at £26,000 free on board, with £1,200 of freight and insurance to the UK. The customs value is £27,200. Duty at 0% is £0. Import VAT at 20% is charged on the customs value plus duty, £27,200, so it is £5,440. 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

Detection: check each supplied sensor against an agreed reference signal or repeatable demonstration, including background noise and interference rejection. Confirm that the displayed result uses the agreed measurement unit.

Calibration: match certificates to instrument and sensor serial numbers. Where apparent charge is claimed, ask the supplier to demonstrate calibration of the complete measurement chain rather than only the display unit.

Recording: save a measurement, reopen it and export a report. Check phase reference, timestamps, sensor identification, software access and English menus without relying on the supplier's computer.

Build and evidence: compare connectors, sensor clamps, leads and power adaptors with the approved sample. Match safety and electromagnetic compatibility reports to the supplied configuration. Use an agreed inspection brief.

What goes wrong

A detector can respond strongly to interference while missing the discharge signal the buyer needs. Relative readings may be presented as calibrated apparent charge, or a demonstration may use a sensor absent from the shipment. Agree the signal source, sensor position and acceptance criteria before approving the sample.

Recording may depend on separately supplied software access, exports may omit sensor settings, and substitute leads can change the response. List the complete kit in the purchase specification and repeat the agreed checks on arrival. A calibration certificate alone does not demonstrate performance on your intended equipment.

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.