Sourcing silicone dielectric gels from China

6% base duty, with conditional 0% suspensions

Read from the UK Trade Tariff on 1 October 2026, heading 3910 covers silicones in primary forms. For dielectric gel material, start by checking the other-silicones line against the formulation. The table also includes specialised insulation, passivation and formulation lines for comparison; they are alternatives requiring an exact description match, rather than interchangeable gel codes. See the wider silicone guide.

The listed lines have a 6% base duty for goods from China, with no anti-dumping or countervailing duty recorded. The solar-panel junction-box line has no suspension. Other listed lines have conditional 0% suspensions. For other silicones, the snapshot names platinum-catalysed addition-curing liquid mixtures for electrical and other specified applications, alongside other named materials. It also includes a mixtures exclusion: ask your broker to reconcile every condition with the actual formulation before claiming relief.

The tariff attaches import and export waste controls. Waste shipment controls apply only to waste material. For a China-to-England shipment requiring notification, the exporter applies to the dispatch authority; shipment must await consent from the Environment Agency and the other authorities involved. Ask your broker to confirm waste status and the applicable procedure. Confirm the commodity code using the composition, supplied form and intended use.

Specify the gel and its curing behaviour

Specify the electrical assembly being encapsulated, whether the gel is supplied ready to use or as separate components, and the cure chemistry. Agree mixing ratio, viscosity at the test temperature, working time, cure schedule, cured penetration or softness, and storage conditions. State whether transparency, re-entry for repair or adhesion to the enclosure matters.

Agree dielectric strength and volume resistivity tests with the specimen thickness, conditioning and test method stated. Trial the gel against the actual board, solder residues, enclosure and dispensing process. Ask for batch results and a retained sample. Use testing and certification support to define the evidence you need.

Before importing a new substance, consider whether UK REACH registration is required; check the position for siloxane monomers and additives. For supply in Great Britain, check chemical classification, labels and packaging under the chemical classification, labelling and packaging rules. Hazardous chemicals supplied for workplace use require safety data sheets. Review each supplied component, rather than relying only on information for the cured gel.

Worked duty example

Illustrative example, not a quote: Illustrative shipment: 5 tonnes of silicone dielectric gel material in sealed drums, without suspension eligibility under 3910 00 00 90, invoiced at £17,000 free on board, with £1,400 of freight and insurance to the UK. The customs value is £18,400. Duty at 6% is £1,104. Import VAT at 20% is charged on the customs value plus duty, £19,504, so it is £3,900.80. Import taxes total £5,004.80; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £1,104 of duty. The import duty and VAT guide explains each step.

Inspection checklist

Identity: match grade, component labels, batch numbers and analysis certificates to the approved formulation.

Cure: mix an arrival sample using the agreed procedure; check working time, bubbles, penetration and uncured pockets.

Electrical performance: check batch test results against the agreed method and test a retained sample where needed.

Packing: check seals, leaks, contamination, production dates and remaining shelf life before releasing stock.

What goes wrong

A gel can cure in a clean sample cup yet remain uncured against production materials. Mixing errors, contamination and incompatible residues can leave soft pockets or bubbles around conductors. A substituted grade may also be harder than the approved sample, making repair difficult. Trial incoming material in the actual assembly before releasing it for production.

A supplier's electrical-use description does not establish suspension eligibility. Keep the composition and cure-chemistry evidence with the broker's classification review, and obtain approval before any formulation change. Plan quality inspection around both unopened packaging and a cured sample.

Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.