Harmonised Standards

Harmonised Standards are European Standards (EN) developed by the European standardisation organisations — CEN, CENELEC, or ETSI — under a mandate from the European Commission, and officially referenced in the Official Journal of the European Union (OJEU). Their key legal property is the presumption of conformity: when a manufacturer applies a harmonised standard in its entirety, they can presume that the corresponding essential requirements of the applicable EU directive are met — without needing to justify compliance with each requirement individually.

How the System Works

EU Directive → specifies Essential Requirements (performance goals, not test methods)
      ↓
European Commission mandates CEN/CENELEC/ETSI to develop standards
      ↓
Standard published in OJEU → becomes Harmonised Standard
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Manufacturer applies standard → earns Presumption of Conformity
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Accredited lab tests to the standard → test report documents compliance
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Manufacturer issues Declaration of Conformity → affixes CE mark

Critical Details About Using Harmonised Standards

OJ References and Transition Periods

When a new or revised harmonised standard is published in the OJEU, a transition period follows during which both the old and new standard are acceptable. After the transition deadline:

• Products tested to the withdrawn standard no longer benefit from the presumption of conformity — even if the test was performed before the deadline
• Technical Files must reference the current version of standards
• If a standard is superseded and your product hasn’t been re-tested, your CE marking may be technically invalid

Example: EN 55032:2015 was the harmonised EMC standard for multimedia equipment. Its revised version EN 55032:2015+A11:2020 was introduced with a transition period. After the transition deadline, only the +A11:2020 version grants the presumption of conformity.

”Applied in Full” Requirement

The presumption of conformity applies only when the standard is applied in full. If a manufacturer applies a standard only partially (e.g., tests emissions but not immunity), they receive no presumption for the parts not covered and must justify compliance with the directive’s essential requirements by alternative means — documented in the Technical File.

No Harmonised Standard Available

For some products or requirements, no harmonised standard exists yet. This is increasingly common for:

• Products covered by the CRA where EN standards for IEC 62443 are still being finalised
• Novel AI systems under the AI Act
• Specific ATEX product types

In these cases, the manufacturer must demonstrate compliance directly against the directive’s essential requirements — a more complex process typically requiring expert analysis and, often, Notified Body involvement.

Key Harmonised Standards for B2B Hardware

Where to Find Current Harmonised Standards

The authoritative source is the Official Journal of the European Union and the Commission’s online harmonised standards database (available at ec.europa.eu). OJEU references include the date of publication and any transition period end dates — always check the current OJEU list before finalising your Technical File, not third-party databases which may lag.

Official References

• Harmonised standards database — European Commission — European Commission (authoritative list of all harmonised standards by directive)
• Regulation (EC) No 765/2008 — Legal basis for harmonised standards system — EUR-Lex