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


Short-circuit currents



Reference EN 60909-3:2010
Title Short-circuit currents in three-phase a.c systems - Part 3: Currents during two separate simultaneous line-to-earth short-circuits and partial short-circuit currents flowing through earth
Project Number 21308
Abstract/Scope IEC 60909-3:2009 specifies procedures for calculation of the prospective short-circuit currents with an unbalanced short circuit in high-voltage three-phase a.c. systems operating at nominal frequency 50 Hz or 60 Hz, i. e.: - currents during two separate simultaneous line-to-earth short circuits in isolated neutral or resonant earthed neutral systems; - partial short-circuit currents flowing through earth in case of single line-to-earth short circuit in solidly earthed or low-impedance earthed neutral systems. The currents calculated by these procedures are used when determining induced voltages or touch or step voltages and rise of earth potential at a station (power station or substation) and the towers of overhead lines. Procedures are given for the calculation of reduction factors of overhead lines with one or two earth wires. This edition constitutes a technical revision. The main changes with respect to the previous edition are: - New procedures are introduced for the calculation of reduction factors of the sheaths or shields and in addition the current distribution through earth and the sheaths or shields of three-core cables or of three single-core cables with metallic non-magnetic sheaths or shields earthed at both ends; - The information for the calculation of the reduction factor of overhead lines with earth wires are corrected and given in the new Clause 7; - A new Clause 8 is introduced for the calculation of current distribution and reduction factor of three-core cables with metallic sheath or shield earthed at both ends; - The new Annexes C and D provide examples for the calculation of reduction factors and current distribution in case of cables with metallic sheath and shield earthed at both ends. This publication is to be read in conjunction with IE C 60909-0:2001. NEW! IEC 60909-3:2009 is also available as IEC Standards+ 60909-3:2009 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.


Current Stage code 6060
Current Stage code date 2010-03-12
Current Stage code deadline 2010-12-01
Deadline date for vote  


Order Voucher  


IEC Technical Body IEC/TC 73
Reference Document IEC 60909-3:2009 (EQV)
ICS 17.220.01 - Electricity. Magnetism. General aspects
29.240.20 - Power transmission and distribution lines
Keywords Short-circuit; Current; Line-to-earth; Partial; Three-phase
Note Supersedes EN 60909-3:2003
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
6060 2010-03-12 2010-12-01 export to doc file  EN  FR  DE
5099 2010-03-01 2010-05-01  
5061 2010-01-25 2010-03-01  
5060 2009-01-13 2009-01-27 export to doc file  EN
5020 2008-11-07 2009-01-09  
3090 2008-08-15 2008-11-30  
5060 2007-11-05 2007-11-19 export to doc file  EN
5020 2007-06-01 2007-11-02  
1090 2007-05-29 2007-06-01  

Implementation Dates

date of Ratification (DOR) (1) 2010-03-01
date of Availability (DAV) (2) 2010-03-12
date of Announcement (DOA) (3) 2010-06-01
date of Publication (DOP) (4) 2010-12-01
date of Withdrawal (DOW) (5) 2013-03-01


Supersedes EN 60909-3:2003
Superseded by  
Normative reference (6) EN 60909-0
IEC/TR 60909-2

(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.