This part of IEC 61000 describes performance requirements, test methods and classification procedures for degrees of protection povided by empty enclosures aganinst electromagnetic disturbances for frequencies between 10 kHz och 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).