What is the EMC-directive (89/336/EEC)
The EMC directive is part of the system of EEC New Approach directives, a series of directives that are created to allow manufacturers to trade freely within the EEC territory. This is done by creating the CE mark, a "trade symbol" showing authorities (not the public) that essential requirements for safety and health are met. EMC stands for Electro Magnetic Compatibility, a term for the behavior of an apparatus in terms of Electro magnetic interference it generates and the immunity to impeached Electro magnetic field on its enclosure and cables.
These safety requirements are the requirements (called essential requirements) an apparatus has to meet to obtain the "presumption of conformity". In case of the EMC directive 89/336/EEC:
- to ensure that any electric or electronic device will create no more then a limited amount of RF interference so that other apparatus are not affected in their correct functioning ( with an emphasis on radio communication (=spectrum protection).
- to ensure that an electric or electronic device will withstand a certain amount of Electro Magnetic fields while operating as intended within specifications.
The bandwidth of the EMC-directive spans 0 - 400 GHz.
How to meet those requirements?
The system of new approach directives is targeted to putting responsibility at the manufacturers. This means that testing and declaring compatibility is the responsibility of the manufacturer. The process of verifying compliance (EMC testing) with the essential requirements is called assessment.
To facilitate the assessment a framework of technical standards is created, called "harmonized standards", of which the publication in the EC official Journal is of binding legal status. The list of standards is created and maintained by European Standardization Institutes such as CENELEC, ISO, ETSI and CEN. Their task is defined in a mandate issued by the European Commission.
As the creation of these standards is thus delegated to a private organization, the EC decided that those standards could not have a legal status. After all, members and writers of standard are industry representatives and not elected parliament members. Therefore, the legal status of harmonized standards is a little less then law. The assessments of an apparatus by application of harmonized standards give the assessor a presumption of compliance (not certainty).
It remains the responsibility of the manufacturer to verify that the goals as defined in the EMC directive (essential requirements) are being met.
In practice this means that compliance to harmonized standards is sufficient to create a sound confidence in compliance to the directive.
A few pitfalls remain, however:
Not all standards for EMC testing cover the full spectrum up till 1 or 2 GHz
No standards cover the defined frequency range up till 400 GHz
Not all standards cover all essential EMC phenomena
It is the responsibility of the manufacturer to ensure that its device wonĄŻt interfere nor be interfered in normal usage. This goes a little beyond complying with harmonized standards.
The attitude of looking beyond standards is called as "the manufacturer showing due diligence towards the requirements of the directive".