IEC 60287-1-1:2023
(Main)Electric cables - Calculation of the current rating - Part 1-1: Current rating equations (100 % load factor) and calculation of losses - General
Electric cables - Calculation of the current rating - Part 1-1: Current rating equations (100 % load factor) and calculation of losses - General
IEC 60287-1-1:2023 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 document provides formulae for current ratings and losses. The formulae given are essentially literal and designedly leave open the selection of certain important parameters. These can 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 can vary widely, the selection of which depends on the country in which the cables are used or will 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).
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Standards Content (Sample)
IEC 60287-1-1
®
Edition 3.0 2023-05
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
IEC 60287-1-1:2023-05 CMV(en)
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IEC 60287-1-1
®
Edition 3.0 2023-05
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Electric cables – Calculation of the current rating –
Part 1-1: Current rating equations (100 % load factor) and calculation of losses –
General
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.060.20 ISBN 978-2-8322-7059-2
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC 60287-1-1:2023 CMV © IEC 2023
CONTENTS
FOREWORD .4
INTRODUCTION .6
1 General .
1 Scope .7
2 Normative references .7
3 Terms, definitions and symbols.8
3.1 Terms and definitions .8
3.2 Symbols .8
4 Permissible current rating of cables . 12
4.1 General . 12
4.2 Buried cables where drying out of the soil does not occur or cables in air . 12
4.2.1 AC cables . 12
4.2.2 DC cables up to 5 kV . 13
4.3 Buried cables w
...
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