EMC Standards & Legislation

EMC / EMI Includes:
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In order to ensure that EMC is not a problem for the wide variety of electronics equipment available today, many EMC standards are used and these are often supported by EMC legislation to ensure that all goods entering an area conform to the required standards.

Evolution of EMC standards & legislation

The basic awareness of the possibilities of interference between various forms of electronics equipment had been around for many years. However the relatively limited use of electronics by today's standards meant that little was undertaken in terms of legislation regarding standards.

Some of the first EMC standards and legislation were introduced in 1979. The Federal Communications Commission, FCC in the USA imposed legal limits on the electromagnetic emissions from all digital equipment. These limits were imposed as a result of the growing availability of digital systems including small calculators and forms of digital equipment that were interfering with wired and radio communications and broadcast systems.

A number of test methods were defined to support this EMC legislation.

A further major step forwards was taken in the 1980s by the European Community. They introduced what was termed a new approach to standardising EMC requirements to enable trade of electronics equipment to be undertaken more freely.

One of the major elements of this was the EMC Directive - 89/336/EC. This EMC standard applied to all equipment that was to be placed on the market of used within the EC. The scope was broad and the EMC Directive encompassed all equipment that was "liable to cause electromagnetic disturbance or the performance of which is liable to be affected by such disturbance."

The EMC Directive from the EC was ground-breaking in terms of EMC standards and legislation as it was the first time that limits had been placed on the immunity of the equipment to interference as well as its emissions. As such the EMC Directive recognised both elements of EMC - operating equipment harmoniously is not just a matter of reducing unwanted emissions as wanted emissions can also cause interference.

The EMC Directive has moved onwards and is now a well-established EMC standard. It has been seen as a success, although there are recognised significant costs associated with it. As a result of its success, many other countries have implemented similar EMC legislation, often utilising the same EMC standards as those employed by the EC. This gives harmonious standards and figures to meet around the globe, thereby allowing for economies of scale.

Common EMC standards

There are several common EMC standards that are widely used. Some of these standards also include other elements apart from just the EMC performance.

  Written by Ian Poole .
  Experienced electronics engineer and author.

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