IEC 61666:2010 ED2

Industrial systems, installations and equipment and industrial products - Identification of terminals within a system

Publication date:   Jun 16, 2021

General information

60.60 Standard published   Aug 19, 2010


TC 3

International Standard

01.080.30   Graphical symbols for use on mechanical engineering and construction drawings, diagrams, plans, maps and in relevant technical product documentation



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IEC 61666:2010 establishes general principles for the identification of terminals of objects within a system, applicable to all technical areas (for example mechanical engineering, electrical engineering, construction engineering, process engineering). They can be used for systems based on different technologies or for systems combining several technologies. This second edition cancels and replaces the first edition of IEC 61666 published in 1997 and edition constitutes a technical revision. It includes the following substantial changes with respect to the previous edition:
- the terminology used in the publication has been adapted to the one used in IEC 81346-1 Ed. 2;
- a more comprehensive description of the designation principles is provided;
- additional examples illustrating terminal designations related to the function aspect and location aspect are provided;
- an additional example illustrating the use of terminal designation sets is provided;
- the former informative Annex A has been turned into a clause in the standard.
IEC 61666:2010 has the status of a horizontal standard in accordance with IEC Guide 108

Life cycle


IEC 61666:1997 ED1


IEC 61666:2010 ED2
60.60 Standard published
Aug 19, 2010


Amended by
IEC 61666:2010/AMD1:2021 ED2