IEC 61360-1:2017 specifies principles for the definition of the properties and associated attributes and explains the methods for representing verbally defined concepts with appropriate data constructs available from IEC 61360-2. It also specifies principles for establishing a hierarchy of classification from a collection of classes, each of which represents a technical concept in the electrotechnical domain or a domain related to electrotechnology. This fourth edition cancels and replaces the third edition published in 2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:.