IEC/TR 62271-208:2009 gives practical guidance for the evaluation and documentation of the external electromagnetic fields which are generated by HV switchgear assemblies and HV/LV prefabricated substations. Basic requirements to measure or calculate the electric and magnetic fields are summarised for switchgear assemblies covered by IEC 62271-200 and IEC 62271-201, and for prefabricated substations covered by IEC 62271-202. This technical report applies to equipment rated for voltages up to and including 52 kV and power-frequencies from 15 Hz to 60 Hz.