Electric cables - Calculation of the current rating - Part 1-1: Current rating equations (100 % load factor) and calculation of losses - General

Applicable to the conditions of steady-state operation of cables at all alternating voltages, and direct voltages up to 5 kV, buried directly in the ground, in ducts, troughs or in steel pipes, both with and without partial drying-out of the soil, as well as cables in air. The term "steady state" is intended to mean a continuous constant current (100 % load factor) just sufficient to produce asymptotically the maximum conductor temperature, the surrounding ambient conditions being assumed constant. Provides formulae for current ratings and losses. The formulae given are essentially literal and designedly leave open the selection of certain important parameters. These may be divided into three groups: - parameters related to construction of a cable (for example, thermal resistivity of insulating material) for which representative values have been selected based on published work; - parameters related to the surrounding conditions, which may vary widely, the selection of which depends on the country in which the cables are used or are to be used; - parameters which result from an agreement between manufacturer and user and which involve a margin for security of service (for example, maximum conductor temperature).

Câbles électriques - Calcul du courant admissible - Partie 1-1: Equations de l'intensité du courant admissible (facteur de charge 100 %) et calcul des pertes - Généralités

Concerne uniquement le fonctionnement en régime permanent des câbles de toutes tensions alternatives et de tensions continues jusqu'à 5 kV, enterrés directement dans le sol, placés dans des fourreaux, caniveaux ou tubes d'acier, avec ou sans assèchement partiel du sol, ainsi que les câbles posés à l'air libre. On entend par "régime permanent" la circulation continue d'un courant constant (facteur de charge 100 %) juste suffisant pour atteindre asymptotiquement la température maximale de l'âme en supposant que les conditions du milieu ambiant restent inchangées. Fournit des formules pour l'intensité du courant et les pertes. Les formules proposées sont essentiellement littérales et laissent en principe libre le choix de certains paramètres importants. Ceux-ci peuvent être divisés en trois groupes: - les paramètres liés à la constitution du câble (par exemple résistance thermique de l'isolant) pour lesquels des valeurs représentatives ont été recueillies, à partir des travaux publiés; - les paramètres liés aux conditions du milieu, qui peuvent varier considérablement; le choix de ceux-ci dépend du pays où les câbles sont ou doivent être utilisés; - les paramètres résultant d'un accord entre fabricant et utilisateur et qui supposent une marge de sécurité en service (par exemple température maximale du conducteur).

General Information

Status
Published
Publication Date
12-Nov-2014
Technical Committee
Drafting Committee
Current Stage
DELPUB - Deleted Publication
Start Date
29-Jan-2021
Completion Date
22-May-2023
Ref Project

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INTERNATIONAL IEC
STANDARD 60287-1-1
Second edition
2006-12
Electric cables –
Calculation of the current rating –
Part 1-1:
Current rating equations (100 % load factor)
and calculation of losses – General
This English-language version is derived from the original
bilingual publication by leaving out all French-language
pages. Missing page numbers correspond to the French-
language pages.
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is also available from the following:
x IEC Web Site (www.iec.ch)
x Catalogue of IEC publications
The on-line catalogue on the IEC web site (www.iec.ch/searchpub) enables you to
search by a variety of criteria including text searches, technical committees
and date of publication. On-line information is also available on recently issued
publications, withdrawn and replaced publications, as well as corrigenda.
x IEC Just Published
This summary of recently issued publications (www.iec.ch/online_news/ justpub)
is also available by email. Please contact the Customer Service Centre (see
below) for further information.
x Customer Service Centre
If you have any questions regarding this publication or need further assistance,
please contact the Customer Service Centre:
Email: custserv@iec.ch
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Fax: +41 22 919 03 00
INTERNATIONAL IEC
STANDARD 60287-1-1
Second edition
2006-12
Electric cables –
Calculation of the current rating –
Part 1-1:
Current rating equations (100 % load factor)
and calculation of losses – General

” IEC 2006 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical,
including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale V
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
For price, see current catalogue

60287-1-1 © IEC:2006 – 3 –
CONTENTS
FOREWORD.5

INTRODUCTION.9

1 General .11

1.1 Scope.11

1.2 Normative references .11

1.3 Symbols .13

1.4 Permissible current rating of cables.19
2 Calculation of losses .25
2.1 AC resistance of conductor.25
2.2 Dielectric losses (applicable to a.c. cables only).31
2.3 Loss factor for sheath and screen (applicable to power frequency a.c. cables
only).31
2.4 Loss factor for armour, reinforcement and steel pipes (applicable to power
frequency a.c. cables only).49
Table 1 – Electrical resistivities and temperature coefficients of metals used.59
Table 2 – Skin and proximity effects – Experimental values for the coefficients k and k .61
s p
Table 3 – Values of relative permittivity and loss factors for the insulation of high-
voltage and medium-voltage cables at power frequency.63
Table 4 – Absorption coefficient of solar radiation for cable surfaces .65

60287-1-1 © IEC:2006 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
ELECTRIC CABLES –
CALCULATION OF THE CURRENT RATING –

Part 1-1: Current rating equations (100 % load factor)

and calculation of losses – General

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60287-1-1 has been prepared by IEC technical committee 20:
Electric cables.
This second edition cancels and replaces the first edition published in 1994, Amendment 1
(1995) and Amendment 2 (2001) The document 20/780/FDIS, circulated to the National
Committees as Amendment 3, led to the publication of this new edition.

60287-1-1 © IEC:2006 – 7 –
The text of this standard is based on the first edition, its Amendments 1 and 2, and the
following documents:
FDIS Report on voting
20/851/FDIS 20/867/RVD
Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of the IEC 60287 series, published under the general title: Electric cables –
Calculation of the current rating, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
60287-1-1 © IEC:2006 – 9 –
INTRODUCTION
This Part 1-1 contains formulae for the quantities R, W , λ and λ .
d 1 2
It contains methods for calculating the permissible current rating of cables from details of the

permissible temperature rise, conductor resistance, losses and thermal resistivities.

Formulae for the calculation of losses are also given.

The formulae in this standard contain quantities which vary with cable design and materials

used. The values given in the tables are either internationally agreed, for example, electrical
resistivities and resistance temperature coefficients, or are those which are generally
accepted in practice, for example, thermal resistivities and permittivities of materials. In this
latter category, some of the values given are not characteristic of the quality of new cables
but are considered to apply to cables after a long period of use. In order that uniform and
comparable results may be obtained, the current ratings should be calculated with the values
given in this standard. However, where it is known with certainty that other values are more
appropriate to the materials and design, then these may be used, and the corresponding
current rating declared in addition, provided that the different values are quoted.
Quantities related to the operating conditions of cables are liable to vary considerably from
one country to another. For instance, with respect to the ambient temperature and soil thermal
resistivity, the values are governed in various countries by different considerations.
Superficial comparisons between the values used in the various countries may lead to
erroneous conclusions if they are not based on common criteria: for example, there may be
different expectations for the life of the cables, and in some countries design is based on
maximum values of soil thermal resistivity, whereas in others average values are used.
Particularly, in the case of soil thermal resistivity, it is well known that this quantity is very
sensitive to soil moisture content and may vary significantly with time, depending on the soil
type, the topographical and meteorological conditions, and the cable loading.
The following procedure for choosing the values for the various parameters should, therefore,
be adopted.
Numerical values should preferably be based on results of suitable measurements. Often
such results are already included in national specifications as recommended values, so that
the calculation may be based on these values generally used in the country in question; a
survey of such values is given in Part 3-1.
A suggested list of the information required to select the appropriate type of cable is given in
Part 3-1.
60287-1-1 © IEC:2006 – 11 –
ELECTRIC CABLES –
CALCULATION OF THE CURRENT RATING –

Part 1-1: Current rating equations (100 % load factor)

and calculation of losses – General

1 General
1.1 Scope
This part of IEC 60287 is applicable to the conditions of steady-state operation of cables at all
alternating voltages, and direct voltages up to 5 kV, buried directly in the ground, in ducts,
troughs or in steel pipes, both with and without partial drying-out of the soil, as well as cables
in air. The term "steady state" is intended to mean a continuous constant current (100 % load
factor) just sufficient to produce asymptotically the maximum conductor temperature, the
surrounding ambient conditions being assumed constant.
This part provides formulae for current ratings and losses.
The formulae given are essentially literal and designedly leave open the selection of certain
important parameters. These may be divided into three groups:
– parameters related to construction of a cable (for example, thermal resistivity of insulating
material) for which representative values have been selected based on published work;
– parameters related to the surrounding conditions, which may vary widely, the selection of
which depends on the country in which the cables are used or are to be used;
– parameters which result from an agreement between manufacturer and user and which
involve a margin for security of service (for example, maximum conductor temperature).
1.2 Normative references
The following referenced documents are indispensable for the application of this document.
For
...


NORME CEI
INTERNATIONALE 60287-1-1
Deuxième édition
2006-12
Câbles électriques –
Calcul du courant admissible –
Partie 1-1:
Equations de l’intensité du courant admissible
(facteur de charge 100 %) et calcul des pertes –
Généralités
Cette version française découle de la publication d’origine
bilingue dont les pages anglaises ont été supprimées.
Les numéros de page manquants sont ceux des pages
supprimées.
Numéro de référence
CEI 60287-1-1:2006(F)
Numérotation des publications
Depuis le 1er janvier 1997, les publications de la CEI sont numérotées à partir de

60000. Ainsi, la CEI 34-1 devient la CEI 60034-1.

Editions consolidées
Les versions consolidées de certaines publications de la CEI incorporant les
amendements sont disponibles. Par exemple, les numéros d’édition 1.0, 1.1 et 1.2

indiquent respectivement la publication de base, la publication de base incorporant

l’amendement 1, et la publication de base incorporant les amendements 1 et 2

Informations supplémentaires sur les publications de la CEI
Le contenu technique des publications de la CEI est constamment revu par la CEI
afin qu'il reflète l'état actuel de la technique. Des renseignements relatifs à cette
publication, y compris sa validité, sont disponibles dans le Catalogue des
publications de la CEI (voir ci-dessous) en plus des nouvelles éditions, amende-
ments et corrigenda. Des informations sur les sujets à l’étude et l’avancement des
travaux entrepris par le comité d’études qui a élaboré cette publication, ainsi que la
liste des publications parues, sont également disponibles par l’intermédiaire de:
• Site web de la CEI (www.iec.ch)
• Catalogue des publications de la CEI
Le catalogue en ligne sur le site web de la CEI (www.iec.ch/searchpub) vous permet
de faire des recherches en utilisant de nombreux critères, comprenant des
recherches textuelles, par comité d’études ou date de publication. Des informations
en ligne sont également disponibles sur les nouvelles publications, les publications
remplacées ou retirées, ainsi que sur les corrigenda.
• IEC Just Published
Ce résumé des dernières publications parues (www.iec.ch/online_news/justpub)
est aussi disponible par courrier électronique. Veuillez prendre contact avec le
Service client (voir ci-dessous) pour plus d’informations.
• Service clients
Si vous avez des questions au sujet de cette publication ou avez besoin de
renseignements supplémentaires, prenez contact avec le Service clients:
Email: custserv@iec.ch
Tél: +41 22 919 02 11
Fax: +41 22 919 03 00
NORME CEI
INTERNATIONALE 60287-1-1
Deuxième édition
2006-12
Câbles électriques –
Calcul du courant admissible –
Partie 1-1:
Equations de l’intensité du courant admissible
(facteur de charge 100 %) et calcul des pertes –
Généralités
” IEC 2006 Droits de reproduction réservés
Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun
procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale V
International Electrotechnical Commission
ɆɟɠɞɭɧɚɪɨɞɧɚɹɗɥɟɤɬɪɨɬɟɯɧɢɱɟɫɤɚɹɄɨɦɢɫɫɢɹ
Pour prix, voir catalogue en vigueur

– 2 – 60287-1-1 © CEI:2006
SOMMAIRE
AVANT-PROPOS.4

INTRODUCTION.8

1 Généralités.10

1.1 Domaine d'application .10

1.2 Références normatives.10

1.3 Symboles .12

1.4 Evaluation de l'intensité admissible du courant dans les câbles.18
2 Calcul des pertes .24
2.1 Résistance de l'âme en courant alternatif .24
2.2 Pertes diélectriques (applicable uniquement aux câbles à courant alternatif).30
2.3 Facteur de pertes dans les gaines ou les écrans (applicable uniquement aux
câbles à courant alternatif à fréquence industrielle).30
2.4 Facteur de pertes dans les armures, les frettages et les tuyaux d'acier
(applicable uniquement aux câbles à courant alternatif à fréquence
industrielle) .48
Tableau 1 – Résistivités électriques et coefficients de variation de la résistivité avec la
température des métaux utilisés .58
Tableau 2 – Effets de peau et de proximité – Valeurs expérimentales pour les
coefficients k et k .60
s p
Tableau 3 – Valeurs numériques de la permittivité relative et du facteur de pertes pour
les isolants utilisés dans les câbles à haute tension et moyenne tension à fréquence
industrielle .62
Tableau 4 – Coefficient d'absorption des rayons solaires pour les surfaces de câbles
suivantes .64

– 4 – 60287-1-1 © CEI:2006
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE

____________
CÂBLES ÉLECTRIQUES –
CALCUL DU COURANT ADMISSIBLE –

Partie 1-1: Equations de l'intensité du courant admissible

(facteur de charge 100 %) et calcul des pertes – Généralités

AVANT-PROPOS
1) La Commission Electrotechnique Internationale (CEI) est une organisation mondiale de normalisation
composée de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a
pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les
domaines de l'électricité et de l'électronique. A cet effet, la CEI – entre autres activités – publie des Normes
internationales, des Spécifications techniques, des Rapports techniques, des Spécifications accessibles au
public (PAS) et des Guides (ci-après dénommés "Publication(s) de la CEI"). Leur élaboration est confiée à des
comités d'études, aux travaux desquels tout Comité national intéressé par le sujet traité peut participer. Les
organisations internationales, gouvernementales et non gouvernementales, en liaison avec la CEI, participent
également aux travaux. La CEI collabore étroitement avec l'Organisation Internationale de Normalisation (ISO),
selon des conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux de la CEI
intéressés sont représentés dans chaque comité d’études.
3) Les Publications de la CEI se présentent sous la forme de recommandations internationales et sont agréées
comme telles par les Comités nationaux de la CEI. Tous les efforts raisonnables sont entrepris afin que la CEI
s'assure de l'exactitude du contenu technique de ses publications; la CEI ne peut pas être tenue responsable
de l'éventuelle mauvaise utilisation ou interprétation qui en est faite par un quelconque utilisateur final.
4) Dans le but d'encourager l'uniformité internationale, les Comités nationaux de la CEI s'engagent, dans toute la
mesure possible, à appliquer de façon transparente les Publications de la CEI dans leurs publications
nationales et régionales. Toutes divergences entre toutes Publications de la CEI et toutes publications
nationales ou régionales correspondantes doivent être indiquées en termes clairs dans ces dernières.
5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa
responsabilité pour les équipements déclarés conformes à une de ses Publications.
6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication.
7) Aucune responsabilité ne doit être imputée à la CEI, à ses administrateurs, employés, auxiliaires ou
mandataires, y compris ses experts particuliers et les membres de ses comités d'études et des Comités
nationaux de la CEI, pour tout préjudice causé en cas de dommages corporels et matériels, ou de tout autre
dommage de quelque nature que ce soit, directe ou indirecte, ou pour supporter les coûts (y compris les frais
de justice) et les dépenses découlant de la publication ou de l'utilisation de cette Publication de la CEI ou de
toute autre Publication de la CEI, ou au crédit qui lui est accordé.
8) L'attention est attirée sur les références normatives citées dans cette publication. L'utilisation de publications
référencées est obligatoire pour une application correcte de la présente publication.
9) L’attention est attirée sur le fait que certains des éléments de la présente Publication de la CEI peuvent faire

l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 60287-1-1 a été établie par le comité d'études 20 de la CEI:
Câbles électriques.
Cette seconde édition annule et remplace la première édition publiée en 1994,
l’amendement 1 (1995) et l’amendement 2 (2001). Le document 20/780/FDIS, qui a circulé
auprès des Comités nationaux en tant qu'amendement 3, a conduit à la publication de cette
nouvelle édition.
– 6 – 60287-1-1 © CEI:2006
Le texte de cette norme est basé sur la première édition, ses amendements 1 et 2, et les

documents suivants :
FDIS Rapport de vote
20/851/FDIS 20/867/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cette norme.

Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.
Une liste de toutes les parties de la CEI 60287, sous le titre général: Câbles électriques –
calcul du courant admissible, est disponible sur le site web de la CEI.
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous "http://webstore.iec.ch" dans les
données relatives à la publication recherchée. A cette date, la publication sera
• reconduite,
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
– 8 – 60287-1-1 © CEI:2006
INTRODUCTION
La présente Partie 1-1 contient des formules relatives aux quantités R, W , λ et λ .
d 1 2
Elle contient des méthodes pour le calcul du courant admissible à partir des détails de

l'accroissement admissible de la température de la résistance des conducteurs, des pertes et

de la résistivité thermique.
Des formules pour le calcul des pertes s’y trouvent aussi.

Les formules de cette norme contiennent des paramètres variant avec la spécification du

câble et les matériaux utilisés. Les valeurs données dans les tableaux sont soit approuvées
internationalement, comme les résistivités électriques et la constante diélectrique des
matériaux, ou bien généralement acceptées dans la pratique, comme les résistivités
thermiques et les permittivités des matériaux. Certaines des valeurs de la dernière catégorie
ne sont pas caractéristiques de la qualité des câbles neufs mais de celle des câbles ayant
déjà subi une longue période d'utilisation. Dans le but d'obtenir des résultats comparables et
reproductibles, les régimes permanents doivent être calculés avec les valeurs indiquées dans
la présente norme. Toutefois, lorsqu'on sait avec certitude que d'autres valeurs sont plus
appropriées aux matériaux et à leur mise en œuvre, ces dernières peuvent alors être utilisées
en déclarant le régime permanent correspondant, pourvu que les différentes valeurs soient
indiquées.
Les données relatives aux conditions de service sont susceptibles de varier considérablement
d'un pays à l'autre. Par exemple, pour ce qui est de la température ambiante et de la
résistance thermique du sol, les valeurs sont régies dans les différents pays par diverses
considérations. Une comparaison hâtive entre les valeurs utilisées dans les différents pays
peut amener des conclusions erronées, si elle n'est pas faite sur des bases communes; par
exemple, on peut compter sur des espérances de vie du câble différentes; de même, dans
certains pays, la spécification est établie sur la valeur maximale de la résistance thermique
du sol, tandis que dans d'autres c'est la valeur moyenne qui est utilisée. En particulier, dans
le cas de la résistivité thermique du sol, il est bien connu que celle-ci est très sensible au taux
d'humidité et peut varier sensiblement dans le temps suivant le type de sol, les conditions
topographiques et météorologiques et la charge du câble.
Le choix des valeurs des différents paramètres sera dès lors effectué de la façon suivante.
Les valeurs numériques devront, de préférence, être basées sur des résultats de mesures
valables. De tels résultats sont déjà souvent inclus dans les spécifications nationales sous
forme de valeurs recommandées, de telle sorte que le calcul peut être exécuté sur la base de
ces valeurs, généralement utilisées dans le pays en question; un examen de ces valeurs est
fait dans la Partie 3-1.
On trouvera un choix d'informations nécessaires pour sélectionner le type de câble approprié
dans la Partie 3-1.
– 10 – 60287-1-1 © CEI:2006
...


IEC 60287-1-1
Edition 2.0 2006-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
Câbles électriques – Calcul du courant admissible –
Partie 1-1: Equations de l’intensité du courant admissible
(facteur de charge 100 %) et calcul des pertes – Généralités
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
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IEC 60287-1-1
Edition 2.0 2006-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
Câbles électriques – Calcul du courant admissible –
Partie 1-1: Equations de l’intensité du courant admissible
(facteur de charge 100 %) et calcul des pertes – Généralités

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
V
CODE PRIX
ICS 29.060.20 ISBN 2-8318-8938-3

– 2 – 60287-1-1 © IEC:2006
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 General .6
1.1 Scope.6
1.2 Normative references .6
1.3 Symbols .7
1.4 Permissible current rating of cables.10
2 Calculation of losses .13
2.1 AC resistance of conductor.13
2.2 Dielectric losses (applicable to a.c. cables only).16
2.3 Loss factor for sheath and screen (applicable to power frequency
a.c. cables only) .16
2.4 Loss factor for armour, reinforcement and steel pipes
(applicable to power frequency a.c. cables only) .25

Table 1 – Electrical resistivities and temperature coefficients of metals used.30
Table 2 – Skin and proximity effects – Experimental values for the coefficients k and k .31
s p
Table 3 – Values of relative permittivity and loss factors for the insulation
of high-voltage and medium-voltage cables at power frequency.32
Table 4 – Absorption coefficient of solar radiation for cable surfaces .33

60287-1-1 © IEC:2006 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRIC CABLES –
CALCULATION OF THE CURRENT RATING –

Part 1-1: Current rating equations (100 % load factor)
and calculation of losses – General

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60287-1-1 has been prepared by IEC technical committee 20:
Electric cables.
This second edition cancels and replaces the first edition published in 1994, Amendment 1
(1995) and Amendment 2 (2001) The document 20/780/FDIS, circulated to the National
Committees as Amendment 3, led to the publication of this new edition.

– 4 – 60287-1-1 © IEC:2006
The text of this standard is based on the first edition, its Amendments 1 and 2, and the
following documents:
FDIS Report on voting
20/851/FDIS 20/867/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60287 series, published under the general title: Electric cables –
Calculation of the current rating, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
60287-1-1 © IEC:2006 – 5 –
INTRODUCTION
This Part 1-1 contains formulae for the quantities R, W , λ and λ .
d 1 2
It contains methods for calculating the permissible current rating of cables from details of the
permissible temperature rise, conductor resistance, losses and thermal resistivities.
Formulae for the calculation of losses are also given.
The formulae in this standard contain quantities which vary with cable design and materials
used. The values given in the tables are either internationally agreed, for example, electrical
resistivities and resistance temperature coefficients, or are those which are generally
accepted in practice, for example, thermal resistivities and permittivities of materials. In this
latter category, some of the values given are not characteristic of the quality of new cables
but are considered to apply to cables after a long period of use. In order that uniform and
comparable results may be obtained, the current ratings should be calculated with the values
given in this standard. However, where it is known with certainty that other values are more
appropriate to the materials and design, then these may be used, and the corresponding
current rating declared in addition, provided that the different values are quoted.
Quantities related to the operating conditions of cables are liable to vary considerably from
one country to another. For instance, with respect to the ambient temperature and soil thermal
resistivity, the values are governed in various countries by different considerations.
Superficial comparisons between the values used in the various countries may lead to
erroneous conclusions if they are not based on common criteria: for example, there may be
different expectations for the life of the cables, and in some countries design is based on
maximum values of soil thermal resistivity, whereas in others average values are used.
Particularly, in the case of soil thermal resistivity, it is well known that this quantity is very
sensitive to soil moisture content and may vary significantly with time, depending on the soil
type, the topographical and meteorological conditions, and the cable loading.
The following procedure for choosing the values for the various parameters should, therefore,
be adopted.
Numerical values should preferably be based on results of suitable measurements. Often
such results are already included in
...


IEC 60287-1-1 ®
Edition 2.1 2014-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
Câbles électriques – Calcul du courant admissible –
Partie 1-1: Equations de l’intensité du courant admissible (facteur de charge
100 %) et calcul des pertes – Généralités

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
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Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
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iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
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A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
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IEC 60287-1-1 ®
Edition 2.1 2014-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electric cables – Calculation of the current rating –

Part 1-1: Current rating equations (100 % load factor) and calculation of losses –

General
Câbles électriques – Calcul du courant admissible –

Partie 1-1: Equations de l’intensité du courant admissible (facteur de charge

100 %) et calcul des pertes – Généralités

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.060.20 ISBN 978-2-8322-1926-3

IEC 60287-1-1 ®
Edition 2.1 2014-11
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
Câbles électriques – Calcul du courant admissible –
Partie 1-1: Equations de l’intensité du courant admissible (facteur de charge
100 %) et calcul des pertes – Généralités

– 2 – IEC 60287-1-1:2006
+AMD1:2014 CSV  IEC 2014
CONTENTS
FOREWORD . 3

INTRODUCTION . 5

1 General . 6

1.1 Scope . 6

1.2 Normative references . 6

1.3 Symbols . 7

1.4 Permissible current rating of cables . 10
2 Calculation of losses . 13
2.1 AC resistance of conductor. 13
2.2 Dielectric losses (applicable to a.c. cables only) . 16
2.3 Loss factor for sheath and screen (applicable to power frequency a.c. cables
only) . 16
2.4 Loss factor for armour, reinforcement and steel pipes (applicable to power
frequency a.c. cables only) . 25

Table 1 – Electrical resistivities and temperature coefficients of metals used . 30
Table 2 – Skin and proximity effects – Experimental values for the coefficients k and k . 31
s p
Table 3 – Values of relative permittivity and loss factors for the insulation
of high-voltage and medium-voltage cables at power frequency . 33
Table 4 – Absorption coefficient of solar radiation for cable surfaces . 34

+AMD1:2014 CSV  IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
ELECTRIC CABLES –
CALCULATION OF THE CURRENT RATING –

Part 1-1: Current rating equations (100 % load factor)

and calculation of losses – General

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 60287-1-1 edition 2.1 contains the second edition (2006-12) [documents 20/851/FDIS and
20/867/RVD] and its amendment 1 (2014-11) [documents 20/1499/FDIS and 20/1547/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions and deletions are displayed in red, with deletions being
struck through. A separate Final version with all changes accepted is available in this
publication.
– 4 – IEC 60287-1-1:2006
+AMD1:2014 CSV  IEC 2014
International Standard IEC 60287-1-1 has been prepared by IEC technical committee 20:
Electric cables.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of the IEC 60287 series, published under the general title: Electric cables –
Calculation of the current rating, can be found on the IEC website.

The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the

publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edit
...

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