[Home](/)/[Resources](/resources)/Harmonised standards for CE marking EUProcess guide # How to Read and Use Harmonised Standards for CE Marking Harmonised standards are the bridge between CE directive essential requirements and practical engineering. Understanding how they create presumption of conformity — and what to do when none exist for your product — is fundamental to building a defensible CE compliance case. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Fharmonised-standards-ce-marking) ## How harmonised standards work 01 Standard is published by a European standards body CEN, CENELEC, or ETSI develop harmonised standards at the request of the European Commission (a 'mandate'). The standards body publishes the standard with an 'EN' prefix. 02 Commission publishes citation in the Official Journal The standard only confers presumption of conformity once its citation is published in the Official Journal of the EU (OJ) under a specific directive. A standard can exist without being OJ-cited — it does not give presumption of conformity until cited. 03 Manufacturer applies the standard By meeting all requirements of a cited harmonised standard, the manufacturer gains presumption of conformity for the essential requirements covered by that standard. This presumption is rebuttable — authorities can challenge it with evidence. 04 Standard may be withdrawn or restricted Standards get updated, amended, or replaced. When an older version is withdrawn from the OJ, it no longer provides presumption of conformity. Manufacturers must use the currently cited version. ## Where to find current harmonised standards * European Commission standardisation website — search by directive for current OJ-cited standards lists * CENELEC, CEN, and ETSI websites — for access to standard text (purchase required for most) * IEC webstore and BSI / DIN / AFNOR national standards bodies — for purchase of adopted versions * Official Journal of the EU (eur-lex.europa.eu) — for authoritative current citation status ## What to do when no harmonised standard applies ### Partially covered product Apply harmonised standards for the aspects they cover. For uncovered essential requirements, conduct a direct assessment against the directive text and use technical literature, previous test results, or common engineering practice. ### New technology with no applicable standard Use Module B+C or another module requiring Notified Body involvement. The Notified Body will assess conformity directly against the essential requirements. ### International standard not yet harmonised International standards (IEC, ISO, ITU) can be used as technical basis for the assessment but do not provide presumption of conformity unless cited in the OJ. Document your assessment carefully. ## Frequently asked questions ### Is using a harmonised standard mandatory? No — harmonised standards are voluntary. Manufacturers can demonstrate conformity with essential requirements by any technically valid method. However, applying harmonised standards is the easiest route because it provides presumption of conformity. Without harmonised standards, you bear the full burden of demonstrating that the product meets essential requirements, which typically means more detailed assessment and often Notified Body involvement. ### What does 'presumption of conformity' actually mean in practice? Presumption of conformity means that if market surveillance authorities test your product against the harmonised standard and it passes, they presume it meets the relevant essential requirements. This presumption can be rebutted only if authorities can show the standard does not fully cover the essential requirements, or that the product does not actually meet the standard. In practice, it shifts the burden of proof significantly in the manufacturer's favour. ### How do I know if a standard citation has been withdrawn? Check the European Commission's harmonised standards database or the Official Journal directly. The OJ citation status is the authoritative source. National standards bodies sometimes list outdated standard numbers — always cross-check with the OJ. When a standard is amended, its citation in the OJ may remain valid under the old version during a transition period. **Disclaimer:** Educational resource only. Standard citation status changes regularly. Always verify with the Official Journal of the EU before finalising your compliance approach. 🇪🇺 CE Marking roadmap for your product Every standard, document, and test that applies — free, no account required. See your free roadmap Related guides * [CE marking overviewCE marking is a manufacturer's declaration that a product meets all applicable EU requirements.](/guides/ce-marking) * [EMC Directive complianceComplete guide to EMC Directive (2014/30/EU) compliance: emissions, immunity, testing requirements, and harmonised standards fo…](/guides/emc-directive-compliance) * [Low Voltage Directive explainedComplete guide to the EU Low Voltage Directive (LVD 2014/35/EU): scope, essential safety requirements, testing, and compliance …](/guides/low-voltage-directive-explained) * [Radio Equipment Directive complianceEverything you need to know about the Radio Equipment Directive: scope, essential requirements, testing, harmonised standards, …](/guides/red-directive-compliance) * [Self-certification vs Notified BodyComplete guide to CE conformity assessment: when you can self-certify under Module A, when you need a Notified Body, and the co…](/guides/self-certification-vs-notified-body)