The following article is derived from various official European publication.
A harmonised standard is a European standard developed by a recognised European Standards Organisation: CEN, CENELEC, or ETSI. It is created following a request from the European Commission to one of these organisations. Manufacturers, other economic operators, or conformity assessment bodies can use harmonised standards to demonstrate that products, services, or processes comply with relevant EU legislation.
Use of harmonised standards
The use of these standards remains voluntary. Manufacturers, other economic operators, or conformity assessment bodies are free to choose another technical solution to demonstrate compliance with the mandatory legal requirements.
Within the context of some directives or regulations, voluntary European standards supporting the implementation of legal requirements are not called "harmonised standards". This legislation is also included in this information service if:
legislation foresees a need for a Commission standardisation request to European Standards Organisations;
publication of references in the Official Journal of the European Union is foreseen as a precondition for presumption of conformity or for other legal effect.
The European directives do not make it mandatory to adopt the harmonized standards, but it is always necessary to prove the conformity of the product with the requirements of the directives applicable to the product. In fact, you can choose other technical and procedural solutions to meet the essential requirements laid down in the directives. These solutions usually require more detailed technical assessments and the involvement of a notified body. While the latter is the main challenge, it is the only option for products which, due to their technical characteristics, cannot be assessed by applying them to the whole of the harmonised standards.
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