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



Reference CLC/TR 50480:2011
Title Determination of cross-sectional area of conductors and selection of protective devices
Project Number 16992
Abstract/Scope This Technical Report applies to low-voltage installations with a nominal system frequency of 50 Hz in which the circuits consist of insulated conductors, cables or busbar trunking systems. It defines the different parameters used for the calculation of the characteristics of electrical wiring systems in order to comply with rules of HD 384/HD 60364. These rules are mainly the following: - current-carrying capacities of the conductors; - characteristics of protective devices in regard to protection against overcurrent; - verification of thermal stress in conductors due to short-circuit current or earth fault current; - fault protection (protection against indirect contact) in TN systems and IT systems; - limitation of voltage drop; - verification of mechanical stresses during short-circuit in busbar trunking systems (BTS) according to EN 60439-2 or powertrack systems according to EN 61534 series. The calculations provided in this Technical Report are only applicable where the characteristics of the circuits are known. For the purpose of this document, when referring to Busbar Trunking Systems, Powertrack Systems are also considered. NOTE 1 Mechanical stress during short-circuit is covered by IEC 60865. NOTE 2 In general these calculations concern supply by HV/LV transformer, but they are also applicable to supply by LV/LV transformer and LV back-up generators. NOTE 3 Effects of harmonics currents are not covered by this document. This Technical Report is also applicable for checking the compliance of the results of calculations performed by software programs for calculation of cross-sectional area of insulated conductors, cross-sectional area of cables and characteristics for selection of busbar trunking systems with HD 384/HD 60364.


Current Stage code 6060
Current Stage code date 2011-02-18
Current Stage code deadline  
Deadline date for vote  


Order Voucher  


IEC Technical Body IEC/TC 64
Reference Document  
ICS 29.060.01 - Electrical wires and cables in general
29.140.50 - Lighting installation systems
Keywords Conductor; Cross-sectional area; Protective device
Note Supersedes R064-003:1998
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
6060 2011-02-18   export to doc file  EN  FR
5099 2011-01-02 2011-01-30  
5060 2010-11-22 2010-12-03 export to doc file  EN
5020 2010-08-20 2010-11-19  
3090 2010-04-19    
5062 2009-03-31 2009-04-22  
5060 2008-12-10 2009-01-09 export to doc file  EN
5020 2008-09-05 2008-12-05 export to doc file  EN
3090 2007-11-30 2008-09-25  
5092 2007-03-21 2007-09-21  
5020 2007-03-21 2007-03-21 export to doc file  EN
4060 2007-01-15 2007-03-20 export to doc file  EN
4020 2006-10-13 2007-01-12 export to doc file  EN
3099 2006-09-18 2006-10-18  
2020 2006-03-15 2006-09-15  
1090 2005-06-01 2005-12-01  

Implementation Dates

date of Ratification (DOR) (1) 2011-01-02
date of Availability (DAV) (2) 2011-02-18
date of Announcement (DOA) (3) -
date of Publication (DOP) (4) -
date of Withdrawal (DOW) (5) -


Supersedes R064-003:1998
Superseded by  
Normative reference (6)  

(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.