Mobile and fixed offshore units - Electrical installations - Part 4: Cables

IEC 61892-4:2019 is applicable to the selection of electrical cables intended for fixed electrical systems in mobile and fixed offshore units, including pipeline, pumping or "pigging" stations, compressor stations and single buoy moorings, used in the offshore petroleum industry for drilling, production, accommodation, processing, storage and offloading purposes.
This document specifies requirements such as those concerning
– types of cables,
– voltage rating of cables,
– cables and wiring for interconnection of equipment,
– current-carrying capacities for continuous service,
– correction factors for different ambient temperature and for short time duty, and
– short-circuit withstand capacity.
This document also gives information on the jet fire test for hydrocarbon (HCF) fire resistant cables.
The reference to fixed electrical systems includes those subjected to vibration due to the movement of the unit, for example, cables installed on a drag chain, and not those intended for repeated flexing. This document does not cover flexible cables, for example, those used on drilling decks for top-drive, or cables for portable equipment.
This document is applicable for cables with a rated voltage up to and including 18/30 kV AC and makes reference to cable standards developed by SC 18A.
For higher voltages, relevant standards developed by TC 20 are applicable.
This document does not apply to
– optical fibre cables,
– sub-sea and umbilical cables;,
– cables supplying downhole pumps, and
– data, telecommunication and radio frequency cables.
This second edition cancels and replaces the first edition published in 2007. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) construction requirements for cables have been removed; reference is made to relevant standards from Subcommittee (SC) 18A;
b) reference is made to standards from IEC TC 20 for cables with rated voltage above 30 kV;
c) tables for current-carrying capacities for defined installations have been removed; reference is made to relevant standards from IEC TC 64;
d) requirements as to the sizes of earth continuity conductors not contained in a cable have been moved to IEC 61892-6;
e) requirements as to fire stops have been deleted;
f) requirements as to tests for cables exposed to drilling fluids have been removed; reference is made to relevant standards from IEC SC 18A;
g) the procedure for tests of jet fire resistant cables has been updated;
h) requirements as to the design of cable systems have been moved to IEC 61892-2;
i) requirements in relation to the installation of cables have been moved to IEC 61892-6.

Unités mobiles et fixes en mer - Installations électriques - Partie 4: Câbles

L'IEC 61892-4:2019 s'applique au choix des câbles électriques destinés aux systèmes électriques fixes dans les unités mobiles et fixes en mer, y compris les canalisations, les stations de pompage ou de raclage, les stations de compression et les systèmes d'amarrage à point unique, qui sont utilisés dans l'industrie pétrolière en mer (offshore) pour le forage, la production, les lieux d'habitation, le traitement, le stockage et le déchargement.
Le présent document spécifie des exigences pour
– les types de câbles,
– la tension assignée des câbles,
– les câbles et le câblage d'interconnexion des équipements,
– les courants admissibles pour le service permanent,
– les facteurs de correction pour une température ambiante différente et pour le service temporaire, et
– la capacité de tenue au court-circuit.
Le présent document fournit également des informations sur l'essai au feu propulsé des câbles résistants aux hydrocarbures (HCF).
La référence aux systèmes électriques fixes inclut ceux qui subissent des vibrations dues au mouvement de l'unité (les câbles installés sur une chaîne de halage, par exemple), mais pas ceux destinés à une flexion répétée. Le présent document ne concerne pas les câbles flexibles (ceux utilisés sur un pont de forage, pour les mécanismes d'entraînement supérieur, ou les câbles pour matériel portable, par exemple).
Le présent document s'applique aux câbles de tension assignée allant jusqu'à 18/30 kV en courant alternatif inclus et fait référence aux normes de câble développées par le Sous-comité 18A.
Pour les tensions supérieures, les normes correspondantes développées par le Comité d'études 20 s'appliquent.
Le présent document ne s'applique pas
– aux câbles à fibres optiques,
– aux câbles sous-marins et câbles ombilicaux,
– aux câbles alimentant les pompes de fond, et
– aux câbles de données, de télécommunication et haute fréquence.
Cette deuxième édition annule et remplace la première édition parue en 2007. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) les exigences de construction des câbles ont été retirées; il est fait référence aux normes pertinentes du Sous-comité 18A;
b) il est fait référence aux normes du Comité d'études 20 de l'IEC pour les câbles dont la tension assignée est supérieure à 30 kV;
c) les tableaux relatifs aux courants admissibles pour les installations définies ont été retirés; il est fait référence aux normes pertinentes du Comité d'études 64 de l'IEC;
d) les exigences en matière de taille des conducteurs de terre non inclus dans un câble sont déplacées vers l'IEC 61892-6;
e) les exigences en matière de coupe-feu ont été supprimées;
f) les exigences en matière d'essai des câbles exposés à des boues de forage sont supprimées; il est fait référence aux normes pertinentes du Sous-comité 18A de l'IEC;
g) la procédure d'essai des câbles résistants au feu propulsé a été mise à jour;
h) les exigences en matière de conception des systèmes de câbles ont été déplacées vers l'IEC 61892-2;
i) les exigences d'installation des câbles ont été déplacées vers l'IEC 61892-6.

General Information

Status
Published
Publication Date
08-Apr-2019
Current Stage
PPUB - Publication issued
Completion Date
09-Apr-2019
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IEC 61892-4
Edition 2.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Mobile and fixed offshore units – Electrical installations –
Part 4: Cables
Unités mobiles et fixes en mer – Installations électriques –
Partie 4: Câbles
IEC 61892-4:2019-04(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61892-4
Edition 2.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Mobile and fixed offshore units – Electrical installations –
Part 4: Cables
Unités mobiles et fixes en mer – Installations électriques –
Partie 4: Câbles
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 47.020.60 ISBN 978-2-8322-6669-4

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61892-4:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 Types and operating conditions of cables ........................................................................ 8

4.1 Types of cables....................................................................................................... 8

4.2 Voltage rating – Power frequency cables ................................................................ 8

4.3 Cables and wiring for interconnection of equipment .............................................. 10

4.4 Cross-sectional areas of conductors and current-carrying capacities .................... 10

4.4.1 Earth conductors ........................................................................................... 10

4.4.2 Current-carrying capacities ............................................................................ 11

4.4.3 Current-carrying capacities for continuous service ......................................... 11

4.4.4 Correction factors for different ambient air temperatures ............................... 14

4.4.5 Correction factors for short time duty ............................................................. 15

4.5 Short-circuit capacity (withstand capability) ........................................................... 18

4.6 Resistance to fire (circuit integrity) ........................................................................ 18

Annex A (informative) Jet fire test for hydrocarbon (HCF) fire resistant cables ..................... 19

A.1 General ................................................................................................................. 19

A.2 HC fire curves ....................................................................................................... 19

A.3 Test requirements ................................................................................................. 19

A.4 Apparatus ............................................................................................................. 19

A.5 Procedure ............................................................................................................. 20

Bibliography .......................................................................................................................... 21

Figure 1 – Time constant of cables ....................................................................................... 16

Figure 2 – Correction factors for 30 min and 1 h service ....................................................... 17

Figure 3 – Correction factor for intermittent service ............................................................... 18

Figure A.1 – HC fire curve according to EN 1363-2 ............................................................... 19

Table 1 – Choice of cables for AC systems ........................................................................... 10

Table 2 – Sizes of earth continuity conductors and equipment earthing connections ............. 10

Table 3 – Coefficient related to maximum permissible temperature of the conductor ............. 11

Table 4 – Current-carrying capacities in continuous service at maximum rated

conductor temperature of 90 °C (ambient air temperature 45 °C) .......................................... 13

Table 5 – Current-carrying capacities in continuous service at maximum rated

conductor temperature of 95 °C (ambient air temperature 45 °C) .......................................... 14

Table 6 – Correction factor for various ambient air temperatures (reference ambient

temperature of 45 °C) ........................................................................................................... 15

---------------------- Page: 4 ----------------------
IEC 61892-4:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MOBILE AND FIXED OFFSHORE UNITS –
ELECTRICAL INSTALLATIONS –
Part 4: Cables
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,

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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 61892-4 has been prepared by IEC technical committee 18:

Electrical installations of ships and of mobile and fixed offshore units.

This second edition cancels and replaces the first edition published in 2007. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) construction requirements for cables have been removed; reference is made to relevant

standards from Subcommittee (SC) 18A;

b) reference is made to standards from IEC TC 20 for cables with rated voltage above 30 kV;

c) tables for current-carrying capacities for defined installations have been removed;

reference is made to relevant standards from IEC TC 64;
---------------------- Page: 5 ----------------------
– 4 – IEC 61892-4:2019 © IEC 2019

d) requirements as to the sizes of earth continuity conductors not contained in a cable have

been moved to IEC 61892-6;
e) requirements as to fire stops have been deleted;

f) requirements as to tests for cables exposed to drilling fluids have been removed;

reference is made to relevant standards from IEC SC 18A;
g) the procedure for tests of jet fire resistant cables has been updated;

h) requirements as to the design of cable systems have been moved to IEC 61892-2;

i) requirements in relation to the installation of cables have been moved to IEC 61892-6.

The text of this International Standard is based on the following documents:
FDIS Report on voting
18/1652/FDIS 18/1662/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

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

A list of all parts in the IEC 61892 series, published under the general title Mobile and fixed

offshore units – Electrical installations, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 6 ----------------------
IEC 61892-4:2019 © IEC 2019 – 5 –
INTRODUCTION

IEC 61892 forms a series of International Standards for safety in the design, selection,

installation, maintenance and use of electrical equipment for the generation, transmission,

storage, distribution and utilization of electrical energy for all purposes in offshore units which

are used for the purpose of exploration or exploitation of petroleum resources.

This part of IEC 61892 incorporates and coordinates, as far as possible, existing rules and

forms a code of interpretation, where applicable, of the requirements of the International

Maritime Organization (IMO), and constitutes a guide for future regulations which may be

prepared and a statement of practice for offshore unit owners, designers, installers and

appropriate organizations.

This document is based on solutions and methods which are in current use, but it is not

intended to impede the development of new or improved techniques.

In this revision, voltage limitations have been removed. However, voltage limitations may be

given in the referenced equipment standards. The removal of voltage limitations is considered

necessary due to the interconnection of, and supply from shore to offshore units. In such

cases, transmission voltages up to 132 kV AC and 150 kV DC are used and higher voltages

are being planned.

The IEC 61892 series aims to constitute a set of International Standards for the offshore

petroleum industry, but it is not intended to prevent their use beyond petroleum installations.

---------------------- Page: 7 ----------------------
– 6 – IEC 61892-4:2019 © IEC 2019
MOBILE AND FIXED OFFSHORE UNITS –
ELECTRICAL INSTALLATIONS –
Part 4: Cables
1 Scope

This part of IEC 61892 is applicable to the selection of electrical cables intended for fixed

electrical systems in mobile and fixed offshore units, including pipeline, pumping or "pigging"

stations, compressor stations and single buoy moorings, used in the offshore petroleum

industry for drilling, production, accommodation, processing, storage and offloading purposes.

This document specifies requirements such as those concerning
– types of cables,
– voltage rating of cables,
– cables and wiring for interconnection of equipment,
– current-carrying capacities for continuous service,

– correction factors for different ambient temperature and for short time duty, and

– short-circuit withstand capacity.

This document also gives information on the jet fire test for hydrocarbon (HCF) fire resistant

cables.

The reference to fixed electrical systems includes those subjected to vibration due to the

movement of the unit, for example, cables installed on a drag chain, and not those intended

for repeated flexing. This document does not cover flexible cables, for example, those used

on drilling decks for top-drive, or cables for portable equipment.

This document is applicable for cables with a rated voltage up to and including 18/30 kV AC

and makes reference to cable standards developed by SC 18A.
For higher voltages, relevant standards developed by TC 20 are applicable.
This document does not apply to
– optical fibre cables,
– sub-sea and umbilical cables;,
– cables supplying downhole pumps, and
– data, telecommunication and radio frequency cables.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.

IEC 60092-350:2014, Electrical installations in ships – Part 350: General construction and test

methods of power, control and instrumentation cables for shipboard and offshore applications

---------------------- Page: 8 ----------------------
IEC 61892-4:2019 © IEC 2019 – 7 –

IEC 60092-353, Electrical installations in ships – Part 353: Power cables for rated voltages

1 kV and 3 kV

IEC 60092-354:2014, Electrical installations in ships – Part 354: Single and three-core power

cables with extruded solid insulation for rated voltages 6 kV (U = 7,2 kV) up to 30 kV

(U = 36 kV)

IEC 60092-360:2014, Electrical installations in ships – Part 360: Insulating and sheathing

materials for shipboard and offshore units, power, control, instrumentation and
telecommunication cables

IEC 60092-376, Electrical installations in ships – Part 376: Cables for control and

instrumentation circuits 150/250 V (300 V)

IEC 61892-1, Mobile and fixed offshore units – Electrical installations – Part 1: General

requirements and conditions

IEC 61892-5, Mobile and fixed offshore units – Electrical installations – Part 5: Mobile units

EN 1363-2:1999, Fire resistance tests – Part 2: Alternative and additional procedures

3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 61892-1 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
braid armour

covering formed from braided metal wires used to protect a cable from external mechanical

effects

[SOURCE: IEC 60092-350:2014, 3.3, modified – The notes to entry have been deleted.]

3.2
armour

covering consisting of metal tape(s) or wires, generally used to protect the cable from external

mechanical effects
[SOURCE: IEC 60050-461:2008, 461-05-06]
3.3
screen

conducting layer or assembly of conducting layers having the function of control of the electric

field within the insulation

Note 1 to entry: It may also provide smooth surfaces at the boundaries of the insulation and assist in the

elimination of spaces at these boundaries
[SOURCE: IEC 60050-461:2008, 461-03-01]
---------------------- Page: 9 ----------------------
– 8 – IEC 61892-4:2019 © IEC 2019
4 Types and operating conditions of cables
4.1 Types of cables

Cables constructed in accordance with IEC 60092-353, IEC 60092-354, and IEC 60092-376

shall be used on mobile and fixed offshore units. All cables shall be low smoke and halogen

free, using materials according to IEC 60092-360. For voltages higher than 30 kV (nominal),

standards from IEC TC 20 shall be used.
NOTE 1 Relevant standard from TC 20 is IEC 60840.

When cables according to standards from TC 20 are used, the cables shall meet the minimum

requirements in IEC 60092-354:2014, Table 3 "Flame spread tests" and Table 4.

In the case of single-core cables for AC systems or cables for circuits with a high content of

harmonics, such as SCR circuits, non-magnetic braid armour or armour shall be used.

Test requirements for cables exposed to drilling fluid are given in IEC 60092-360:2014,

Annex D.

NOTE 2 IEC 60092-350, IEC 60092-353, IEC 60092-354 and IEC 60092-376 specify braid armour only. However,

in some countries, cables with armour are also used for offshore applications.
4.2 Voltage rating – Power frequency cables

The maximum rated voltage (U) considered in this document for power frequency cables is

30 kV.
In the voltage designation of cables U / U / (U ):
0 m

– U is the rated power frequency voltage between conductor and earth or the metallic

screen for which the cable is designed;

– U is the rated power frequency voltage between conductors for which the cable is

designed;

– U is the maximum value of the highest system voltage which may be sustained under

normal operating conditions at any time and at any point in the system. It excludes

transient voltage conditions and rapid disconnection of loads.

is chosen to be equal to or greater than the highest voltage of the three-phase system.

Where cables are permitted for use on circuits where the nominal system voltage exceeds the

rated voltage of the cables, the nominal system voltage shall not exceed the highest system

voltage (U ) of the cable.

Careful consideration shall be given to cables subjected to voltage surges associated with

highly inductive circuits to ensure that they are of a suitable voltage rating.

The choice of standard cables of appropriate voltage designations for particular systems

depends upon the system voltage and the system earthing arrangements.

The rated voltage of any cable shall not be lower than the nominal voltage of the circuit for

which it is used. To facilitate the choice of the cable, the values of U recommended for cables

to be used in three-phase systems are listed in Table 1 in which systems are divided into the

following three categories.
• Category A

This category comprises those systems in which any phase conductor that comes into contact

with earth or an earth conductor is automatically disconnected from the system.
• Category B
---------------------- Page: 10 ----------------------
IEC 61892-4:2019 © IEC 2019 – 9 –

This category comprises those systems that, under fault conditions, are operated for a short

time, not exceeding 8 h on any occasion, with one phase earthed.

For example, for a 13,8 kV system of Category A or B, the cable should have a rated voltage

not less than 8,7/15 kV.

In a system where an earth fault is not automatically and promptly eliminated, the increased

stresses on the insulation of cables during the earth fault are likely to affect the life of the

cables to a certain degree. If the system is expected to be operated fairly often with a

sustained earth fault, it may be preferable to use cables suitable for Category C. In any case,

for classification as Category B, the expected total duration of earth faults in any year should

not exceed 125 h.
• Category C
This category comprises all systems that do not fall into Categories A and B.

The nominal system voltages from 3,3 kV to 30 kV shown in Table 1 are generally in

accordance with IEC 60038:2009, series I. For nominal system voltages intermediate between

these standard voltages and also between 0,6/1 kV and 1,8/3,3 kV, the cables should be

selected with a rated voltage not less than the next higher standard value. For example: a first

earth fault with one phase earthed causes a √3 higher voltage between the phases and earth

during the fault. If the duration of this earth fault exceeds the times given for Category B, then

according to Table 1, for a 17,5 kV system, the cable is to have a rated voltage not less than

12/20 kV.

A DC voltage to earth of up to a maximum of 1,5 times the AC U voltage may be used.

However, consideration should be given to the peak value when determining the voltage of

DC systems derived from rectifiers, bearing in mind that smoothing does not modify the peak

value when the semiconductors are operating on an open circuit.
---------------------- Page: 11 ----------------------
– 10 – IEC 61892-4:2019 © IEC 2019
Table 1 – Choice of cables for AC systems
System voltage System Minimum rated voltage
category of cable
U /U
Nominal voltage Maximum Unscreened Single-core or
sustained screened
voltage
kV kV kV kV
up to 0,25 0,30 A, B or C 0,15 / 0,25 −
1 1,2 A, B or C 0,6 / 1,0 0,6 / 1,0
3 3,6 A or B 1,8 / 3,0 1,8 / 3,0
3 3,6 C 3,6 / 6,0
6 7,2 A or B 3,6 / 6,0
6 7,2 C 6,0 / 10
10 12 A or B 6,0 / 10
10 12 C 8,7 / 15
15 17,5 A or B 8,7 / 15
15 17,5 C 12 /20
20 24 A or B 12 / 20
20 24 C 18 / 30
30 36 A or B 18 / 30
4.3 Cables and wiring for interconnection of equipment

Cables external to an enclosure shall comply with the requirements of this document.

The minimum size for conductors in IEC 60092-350:2014, Table 1, shall be used. Smaller

cable sizes may be considered; however, the mechanical strength and insulation qualities of

such cables and wiring shall not affect the reliability and safety of the system of which they

form a part.
4.4 Cross-sectional areas of conductors and current-carrying capacities
4.4.1 Earth conductors

The cross-sectional area of an earth conductor contained in a cable is given in Table 2.

Table 2 – Sizes of earth continuity conductors and equipment earthing connections

Arrangement of earth conductor Cross-section Q Minimum cross-section
of associated of earth conductor
current-carrying
conductor (one
phase or pole)
Insulated earth conductor in cable for fixed installation. Q ≤ 16 Q
Copper braid armour of cable for fixed installation according Q > 16 50 % of the
to IEC 60092-350:2014, 4.8.1. current-carrying
conductor, but not less
than 16 mm
For earth conductors not incorporated in a cable, see IEC 61892-6:2019, Table 5.
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IEC 61892-4:2019 © IEC 2019 – 11 –
4.4.2 Current-carrying capacities

The procedure for cable selection employs rating factors to adjust the current-carrying

capacities for different ambient temperatures, short time duty, the mutual heating effects of

grouping with other cables, and methods of installation. Guidance on the use of these factors

is given in 4.4.3 to 4.4.5.
4.4.3 Current-carrying capacities for continuous service

Continuous service for a cable shall be considered, for the purpose of this document, as a

current-carrying service with constant load having a duration longer than three times the

thermal time constant of the cable, i.e., longer than the critical duration (see Figure 1).

The
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