This part of IEC 61000 describes performance requirements, test methods and classification
procedures for degrees of protection provided by empty enclosures against electromagnetic
disturbances for frequencies between 10 kHz and 40 GHz. The shielding performance is to be
measured prior to the installation of internal electrical and/or electronic equipment and
components. This shielding protection is measured for the purpose of demonstrating that the
enclosure provides adequate shielding of electromagnetic energy to support acceptable
performance of the complete assembled units when tested to applicable IEC standards.
However, it should be noted that satisfactory performance of an empty enclosure does not
necessarily ensure that the completed units will pass all EMC performance test standards for
the operating equipment (see discussion in annex A).
The purpose of this standard is to provide a repeatable means for evaluating the
electromagnetic shielding performance of empty mechanical enclosures, including cabinets and
subracks, and to specify a marking code to allow a manufacturer to select an enclosure with a
known capability for attenuating electromagnetic fields. The requirements for immunity to
various types of electromagnetic disturbances, including lightning and high-altitude electromagnetic
pulse (HEMP) will need to be considered by manufacturers when determining the
need for application of this standard for specific equipment and applications, and for the
specific enclosure shielding requirements which are necessary as a function of frequency.
The adoption of the classification system in this standard will, whenever possible, promote
uniformity in methods of describing the protection against electromagnetic stresses provided by
the enclosure. This includes protection of equipment inside the enclosure from external
electromagnetic stresses, as well as protection of external equipment from internally generated
Technical Committees responsible for enclosures may decide on the extent and manner in
which the classification defined in this standard is used in their standards and to define
enclosure as it applies to their equipment. However, the tests and performance categories
must not differ from those specified in this standard. An informative guide for the details to be
specified in relevant enclosure product standards is given in annex B.