This document was developed by a Joint Working Group of IEC, ILAC and IAF for assessment teams conducting unified assessments in the electrotechnical sector and provides background and guidance on how unified assessments are prepared, conducted and completed. This document contains guidance on the management of the on-site assessment of Certification Bodies and Testing Laboratories against ISO/IEC 17065 and ISO/IEC 17025, in order to harmonize and simplify unified assessments in the electrotechnical sector. The guidance emphasizes the importance of assessment as a management tool for monitoring and verifying the effective competence and capability in the relevant elements of conformity assessment in testing and certification of electrotechnical equipment and components. The use of this guidance may differ according to the size, nature and complexity of the organizations to be assessed, as well as the objectives and scopes of the assessments to be conducted.