International Standards and Conformity Assessment for all electrical, electronic and related technologies



Reference EN 61666:2010
Title Industrial systems, installations and equipment and industrial products - Identification of terminals within a system
Project Number 22404
Abstract/Scope 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.


Current Stage code 6060
Current Stage code date 2010-09-17
Current Stage code deadline 2011-06-01
Deadline date for vote  


Order Voucher  


IEC Technical Body IEC/TC 3
Reference Document IEC 61666:2010 (EQV)
ICS 01.080.30 - Graphical symbols for use on mechanical engineering and construction drawings, diagrams, plans, maps and in relevant technical product documentation
Keywords Industrial; Installation; Product; Identification; Terminal
Note Supersedes EN 61666:1997 * Corrigendum to German version of EN 61666:2010 issued October 2010
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
6060 2010-09-17 2011-06-01 export to doc file  EN  FR  DE
5099 2010-09-01 2010-09-30  
5060 2010-07-20 2010-08-03 export to doc file  EN
5020 2010-05-14 2010-07-16  
3090 2010-01-15 2010-01-31  
5060 2009-09-21 2009-10-05 export to doc file  EN
5020 2009-04-24 2009-09-18  
1090 2009-04-21 2009-04-24  

Implementation Dates

date of Ratification (DOR) (1) 2010-09-01
date of Availability (DAV) (2) 2010-09-17
date of Announcement (DOA) (3) 2010-12-01
date of Publication (DOP) (4) 2011-06-01
date of Withdrawal (DOW) (5) 2013-09-01


Supersedes EN 61666:1997
Superseded by  
Normative reference (6) EN 60445:2010
HD 457 S1:1985
EN 61082-1
EN 81346-1:2009
IEC 81714-3:2004
IEC 60417-DB:2002

(1) Date of ratification (dor) date when the Technical Board notes the approval of an EN (and HD for CENELEC), from which time the standard may be said to be approved

(2) Date of availability (dav) date when the definitive text in the official language versions of an approved CEN/CENELEC publication is distributed by the Central Secretariat

(3) Date of announcement (doa) latest date by which the existence of an EN (and HD for CENELEC), a TS or a CWA has to be announced at national level

(4) Date of publication (dop) latest date by which an EN has to be implemented at national level by publication of an identical national standard or by endorsement

(5) Date of withdrawal (dow) latest date by which national standards conflicting with an EN (and HD for CENELEC) have to be withdrawn

(6) This list of normative references is purely indicative. The only official list of normative reference is the list of the published standard.