IEC 60779:2020 specifies the test procedures, conditions and methods for determining the main performance parameters and operational characteristics of electroslag remelting furnaces. Measurements and tests that are solely used for the verification of safety requirements of the installations are outside the scope of this document and are covered by IEC 60519-1 and IEC 60519-8. This third edition cancels and replaces the second edition published in 2005. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - the structure has been redrafted according to IEC 60398:2015; - the scope and object have been redrafted; - the terms/definitions, normative references and bibliography have been updated and completed; - all test methods and content from IEC 60779:2005 that have been included in IEC 60398:2015 have been removed to avoid any duplication.