Does a change of plastic colour need retesting?

Main answer · Wecent Editorial Team

Short answer: Not always a full retest, but it needs a documented assessment. The housing plastic is usually a safety-critical material with a flammability rating, and the safety report often lists the approved material by grade, sometimes with colour. A colourant change can affect flammability rating, and the pigment brings its own RoHS and REACH questions. Check whether the material and colour are covered in the safety report, get RoHS/REACH evidence for the coloured material, and update the technical file.

Why colour can matter

• Flammability: housing plastics for mains chargers typically need a specified flammability rating. Ratings can be colour-dependent for some materials, and the material supplier’s certification indicates which colours are covered.
• Chemicals: pigments and masterbatches can contain restricted substances. RoHS and REACH evidence should cover the coloured material, not just the natural resin.
• Heat: dark colours absorb more sunlight; a charger’s internal heating isn’t greatly changed by colour, but surface temperatures in sun can be.

What to check

1. The safety test report’s critical components list: does it name the housing material by grade, and is the new colour included or allowed?
2. The material supplier’s flammability certification for that grade and colour.
3. RoHS test data or declaration for the coloured material.
4. REACH SVHC statement covering the colour masterbatch.
5. Any coating or paint added, which may need its own data.

Possible outcomes

• Covered: material and colour already listed or allowed; document and update the file.
• Report update: the test lab assesses and amends the report, sometimes with limited testing.
• New tests: if a different material grade or coating is used, more testing may be needed.

Ask the lab

The lab that issued the safety report can say whether the change needs evaluation. That is usually quicker and cheaper than guessing.

Documentation

Record the colour variants in the technical file with model or SKU identifiers, material details and evidence. Make sure labels and DoC identify the variants correctly.

Other effects

Colour can also affect logo legibility, light-pipe visibility on LED indicators, and how scratches show. These are commercial rather than compliance points, but worth checking on samples.

Confirm with Wecent the housing material grade and supplier documentation for each colour before approving the variants.

Where this answer says confirm with Wecent, the detail is not published on the product page and has to come from the datasheet or the factory. General facts come from the standards bodies, regulators or device makers named in the text.