IEC 60092-352:2005

Electrical installations in ships - Part 352: Choice and installation of electrical cables

This standard provides the basic requirements for the choice and installation of cables intended for fixed electrical systems on board ships at voltages (U) up to and including 15 kV. The reference to fixed systems includes those that are subjected to vibration (due to the movement of the ship) or movement (due to motion of the ship) and not to those that are intended for frequent flexing. Cables suitable for frequent or continual flexing use are detailed in other IEC specifications e.g. IEC 60227 and IEC 60245, and their uses on board ship is restricted to those situations which do not directly involve exposure to a marine environment e.g. portable tools or domestic appliances.

General Information

• Status: Published
• Publication Date: 26-Sep-2005
• ICS: 29.060.20 - Cables
• ICS: 33.120.30 - RF connectors
• ICS: 47.020.60 - Electrical equipment of ships and of marine structures
• Technical Committee: SC 18A - Electric cables for ships and mobile and fixed offshore units
• Drafting Committee: MT 2 - TC 18/SC 18A/MT 2
• Current Stage: PPUB - Publication issued
• Start Date: 27-Sep-2005
• Completion Date: 15-May-2006

Relations

• Revises: IEC 60092-352:1997/AMD1:1998 - Amendment 1 - Electrical installations in ships - Part 352: Choice and installation of cables for low-voltage power systems
• Effective Date: 05-Sep-2023
• Revised: IEC 60092-352:2025 - Electrical installations in ships - Part 352: Selection, installation, and operating conditions of cables
• Effective Date: 05-Sep-2023
• Revises: IEC 60092-352:1997 - Electrical installations in ships - Part 352: Choice and installation of cables for low-voltage power systems
• Effective Date: 05-Sep-2023

Overview

IEC 60092-352:2005 - “Electrical installations in ships - Part 352: Choice and installation of electrical cables” sets out the basic requirements for selecting and installing cables for fixed shipboard electrical systems at voltages up to and including 15 kV. It covers cables exposed to ship motion and vibration but excludes cables intended for frequent flexing (those are covered by IEC 60227 and IEC 60245). The standard is part of the IEC 60092 series for shipboard electrical installations and aligns cable selection with marine operating, safety and fire-performance requirements.

Key topics

• Scope and cable types: guidance on appropriate cable types and construction for fixed shipboard use (power, control, instrumentation).
• Voltage rating and insulation: selection criteria for systems up to 15 kV, including insulation materials (references to EPR and XLPE developments via IEC 60092-351).
• Conductor sizing and current carrying capacity: tables and methods for choosing conductor cross-sectional area, continuous and intermittent ratings, and correction factors for groupings and ambient temperature.
• Voltage drop & lighting load estimation: procedures to calculate acceptable voltage drop and to size lighting circuits.
• Short‑circuit withstand and earthing: selection to ensure sufficient short‑circuit capacity and correct sizes for earth continuity and equipment earthing conductors.
• Mechanical and environmental installation rules: bending radii, supports, fixing, protection against mechanical damage, tensile stress, EMI considerations and installation in conduits, ducts, battery compartments and refrigerated spaces.
• Fire performance & penetrations: fire‑resistant installation practices, fire stops for bulkhead/deck penetrations, and guidance on limiting flame spread.
• Terminations, joints and splicing: approved practices for cable ends, joints, tappings and joint boxes.
• Annexed data: tabulated current carrying capacities, correction factors, fire stop guidance and splicing recommendations.

Applications

IEC 60092-352 is intended for:

• Ship designers and naval architects specifying power distribution and cable routing.
• Marine electrical engineers and shipbuilders implementing cable installations.
• Classification societies and inspectors assessing compliance with ship electrical standards.
• Cable manufacturers and suppliers creating shipboard cable solutions.
• Offshore-platform electrical teams and ship repair yards planning retrofits or maintenance.

Practical use cases include choosing cable types for main switchboards, distribution feeders, propulsion and auxiliary systems, specifying bending radii and supports during installation, and verifying earthing/short‑circuit capability.

Related standards

• IEC 60092 series (e.g., Parts 350, 351, 353, 354, 359, 376, 401)
• IEC 60227 and IEC 60245 (cables for frequent flexing)
• Other IEC shipboard parts referenced for system design, testing and materials

Keywords: IEC 60092-352, electrical installations in ships, shipboard cables, cable installation, marine cable selection, current carrying capacity, cable fire performance, bending radius, cable joints.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 60092-352
Third edition
2005-09
Electrical installations in ships –
Part 352:
Choice and installation of electrical cables
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.
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INTERNATIONAL IEC
STANDARD 60092-352
Third edition
2005-09
Electrical installations in ships –
Part 352:
Choice and installation of electrical cables

 IEC 2005  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: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale X
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 60092-352  IEC:2005(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.8
2 Normative references .8
3 Types, construction, installation and operating conditions of cables .9
3.1 Types of cables .9
3.2 Voltage rating.10
3.3 Cross-sectional areas of conductors and current carrying capacities .11
3.4 Voltage drop.15
3.5 Estimation of lighting loads.15
3.6 Parallel connection of cables.15
3.7 Separation of circuits.16
3.8 Short circuit capacity (withstand capability). .16
3.9 Conductor .16
3.10 Insulation material.16
3.11 Screen, core screen or shield .16
3.12 Sheathing material .16
3.13 Metallic braid or armour.17
3.14 Fire performance.17
3.15 Cable runs.18
3.16 Cable installation methods in relation to electromagnetic interference .19
3.17 Mechanical protection .19
3.18 Bending radius .20
3.19 Supports and fixing .21
3.20 Cables penetrating bulkheads and decks.21
3.21 Installation in metallic pipes or conduits or trunking.22
3.22 Installation in non-metallic pipes, conduits, trunking, ducts or capping and
casing .22
3.23 Installation in battery compartments .23
3.24 Installation in refrigeration spaces .23
3.25 Tensile stress.23
3.26 Special precautions for single core cables for a.c. wiring.23
3.27 Cable ends.24
3.28 Joints and tappings (branch circuits) .25
3.29 Joint boxes.25

Annex A (informative) Tabulated current carrying capacities – Defined installations.29
Annex B (informative) Tabulated current carrying capacities – General installations .40
Annex C (informative) Fire stops.47
Annex D (informative) Cable splicing .48

Bibliography.49

60092-352  IEC:2005(E) – 3 –
Figure 1 – Correction factors for half hour and one hour service .26
Figure 2 – Time constant of cables .27
Figure 3 – Correction factor for intermittent service.28

Table 1 – Choice of cables for a.c. systems .11
a
Table 2 – Sizes of earth continuity conductors and equipment earthing connections .12
Table 3 – Correction factor for various ambient air temperatures .14
Table 4 – Bending Radii for cables rated up to 1,8/3 kV.20
Table 4 A – Bending Radii for cables rated at 3,6/6,0(7,2) kV and above .20
Table A.1 – Current carrying capacities in amperes .32
Table A.2 – Current carrying capacities in amperes .33
Table A.3 – Current carrying capacities in amperes .34
Table A.4 – Current carrying capacities in amperes .35
Table A.5 – Current carrying capacities in amperes .36
Table A.6 – Correction factors for groups of more than one circuit or of more than one
multi-core cable to be used with current carrying capacities of Tables A.1 to A.5 .37
Table A.7 – Correction factors for group of more than one multi-core cable to be
applied to reference ratings for multi-core cables in free air – Method of installation E
in Tables A.1 to A.5 .38
Table A.8 – Correction factors for groups of more than one circuit of single-core cables
to be applied to reference rating for one circuit of single-core cables in free air –
Method of installation F in Tables A.1 to A.5 .39
Table B.1 – Current carrying capacities in continuous service at maximum rated
conductor temperature of 60 °C .42
Table B.2 – Current carrying capacities in continuous service at maximum rated
conductor temperature of 70 °C .43
Table B.3 – Current carrying capacities in continuous service at maximum rated
conductor temperature of 85 °C .44
Table B.4 – Current carrying capacities in continuous service at maximum rated
conductor temperature of 90 °C .45
Table B.5 – Current carrying capacities in continuous service at maximum rated
conductor temperature of 95 °C .46

– 4 – 60092-352  IEC:2005(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 352: Choice and installation of electrical 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
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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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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
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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 60092-352 has been prepared by subcommittee 18A: Cables and
cable installations, of IEC technical committee TC 18: Electrical installations of ships and of
mobile and fixed offshore units.
This third edition cancels and replaces the second edition published in 1997, of which it
constitutes a technical revision. Main changes with respect to the second edition relate to:
− sizes of earth continuity conductors and equipment earthing connections;
− bending radii for cables rated at 3,6/6,0 (7,2) kV and above;
− current carrying capacities in amperes at core temperatures of 70 °C and 90 °C;
− tabulated current carrying capacities – defined installations.

60092-352  IEC:2005(E) – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
18A/277/FDIS 18A/280/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.
IEC 60092 consists of the following parts under the general title Electrical installations in
ships:
Part 101: Definitions and general requirements
Part 201: System design – General
Part 202: System design – Protection
Part 203: System design – Acoustic and optical signals
Part 204: System design – Electric and electrohydraulic steering gear
Part 301: Equipment – Generators and motors
Part 302: Low-voltage switchgear and controlgear assemblies
Part 303: Equipment – Transformers for power and lighting
Part 304: Equipment – Semiconductor convertors
Part 305: Equipment – Accumulator (storage) batteries
Part 306: Equipment – Luminaires and accessories
Part 307: Equipment – Heating and cooking appliances
Part 350: Shipboard power cables – General construction and test requirements
Part 351: Insulating materials for shipboard and offshore units, power, control,
instrumentation, telecommunication and data cables
Part 352: Choice and installation of electric cables
Part 353: Single and multicore non-radial field power cables with extruded solid insulation
for rated voltages 1 kV and 3 kV
Part 354: Single- and three-core power cables with extruded solid insulation for rated
voltages 6 kV (Um = 7,2 kV) up to 30 kV (Um = 36 kV)
Part 359: Sheathing materials for shipboard power and telecommunication cables
Part 373: Shipboard telecommunication cables and radio-frequency cables – Shipboard
flexible coaxial cables
Part 374: Shipboard telecommunication cables and radio-frequency cables – Telephone
cables for non-essential communication services
Part 375 Shipboard telecommunication cables and radio-frequency cables – General
instrumentation, control and communication cables
Part 376: Cables for control and instrumentation circuits 150/250 V (300 V)
Part 401: Installation and test of completed installation
Part 501: Special features – Electric propulsion plant
Part 502: Tankers – Special features
Part 503: Special features – A.C. supply systems with voltages in the range above 1 kV up
to and including 11 kV
Part 504: Special features – Control and instrumentation

– 6 – 60092-352  IEC:2005(E)
Part 506: Special features – Ships carrying specific dangerous goods and materials
hazardous only in bulk
Part 507: Pleasure craft
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.
A bilingual version of this publication may be issued at a later date.

60092-352  IEC:2005(E) – 7 –
INTRODUCTION
IEC 60092 forms a series of International Standards concerning electrical installations in sea-
going ships and fixed or mobile offshore units, incorporating good practice and co-ordinating
as far as possible existing rules.
These standards form:
– a code of practical interpretation and amplification of the requirements of the International
Convention on Safety of Life at Sea;
– a guide for future regulations which may be prepared and
– a statement of practice for use by owners and builders of ships and fixed or mobile and
offshore units and other appropriate organisations.
This revision of IEC 60092-352 has been prepared by Maintenance Team 1 of IEC SC 18A, to
update and include developments identified in other parts of the 60092 series of standards
applicable to electric cables for electrical installations in ships, viz:
− the increase in maximum rated conductor temperature during normal operation for EPR,
XLPE type insulations – see IEC 60092-351 – and the effect on current carrying capacities;
− the publication of IEC 60092-376 covering cables for control and instrumentation
150/250V(300V);
− changes in test methods to demonstrate the capability of cables to continue to operate in
fire conditions and to limit the spread of flame;
− the inclusion of a method for the determination of current carrying capacities based upon
those that have been accepted and established in other applications of cable use. This
method has been derived from a technical basis and allows a greater choice of use in
different installation methods as opposed to that currently specified, which was
established from experimental data on a limited number of cables and installation
information. The existing ratings are included as informative annexes A and B, and their
use is valid under certain conditions, e.g. refurbishment of ships;
− the inclusion of a method for the determination of the cross-sectional areas of earthing
conductors based on the current carrying capacities of the fuse or circuit protection device
installed to protect the circuit.
NOTE Guidance for the use and installation of cables for offshore applications is being prepared jointly by
SC18A, MT 2 and TC 18, MT 18, and will be issued by TC 18, MT 18.

– 8 – 60092-352  IEC:2005(E)
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 352: Choice and installation of electrical cables

1 Scope
This standard provides the basic requirements for the choice and installation of cables
intended for fixed electrical systems on board ships at voltages (U) up to and including 15 kV.
The reference to fixed systems includes those that are subjected to vibration (due to the
movement of the ship) or movement (due to motion of the ship) and not to those that are
intended for frequent flexing. Cables suitable for frequent or continual flexing use are detailed
in other IEC specifications e.g. IEC 60227 and IEC 60245, and their uses on board ship is
restricted to those situations which do not directly involve exposure to a marine environment
e.g. portable tools or domestic appliances.
The following types and applications of cables are not included:
− optical fibre cables;
− sub-sea and umbilical cables;
− data, telecommunication and radio frequency cables;
− the choice and installation of cables for use on offshore units.
2 Normative references
The following referenced documents are indispensable for the application 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 60092-101, Electrical installations in ships – Part 101: Definitions and general
requirements
IEC 60092-201:1994, Electrical installations in ships – Part 201: System design – General
IEC 60092-203, Electrical installations in ships – Part 203: System design – Acoustic and
optical signals
IEC 60092-350:2001, Electrical installations in ships – Part 350: Shipboard power cables –
General construction and test requirements
IEC 60092-351, Electrical installations in ships – Part 351: Insulating materials for shipboard
and offshore units, power, control, instrumentation, telecommunication and data cables
IEC 60092-353:1995, Electrical installations in ships – Part 353: Single and multicore non-
radial field power cables with extruded solid insulation for rated voltages 1 kV and 3 kV
Amendment 1 (2001)
IEC 60092-354, 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 =
m m
36 kV)
60092-352  IEC:2005(E) – 9 –
IEC 60092-359, Electrical installations in ships – Part 359: Sheathing materials for shipboard
power and telecommunication cables
IEC 60092-376, Electrical installations in ships – Part 376: Cables for control and
instrumentation circuits 150/250 V (300 V)
IEC 60228:2004, Conductors of insulated cables
IEC 60287 (all parts), Electric cables – Calculation of the current rating
IEC 60331-21:1999, Tests for electric cables under fire conditions – Circuit integrity – Part 21:
Procedures and requirements – Cables of rated voltage up to and including 0,6/1,0 kV
IEC 60331-31:2002, Tests for electric cables under fire conditions – Circuit integrity – Part 31:
Procedures and requirements for fire with shock – Cables of rated voltage up to and including
0,6/1,0 kV
IEC 60332-1-2:2004, Tests on electric and optical fibre cables under fire conditions – Part 1-2:
Test for vertical flame propagation for a single insulated wire or cable – Procedure for 1 kW
pre-mixed flame
IEC 60332-3-22:2000, Tests on electric cables under fire conditions – Part 3-22: Test for
vertical flame spread of vertically-mounted bunched wires or cables – Category A
IEC 60533:1999, Electrical and electronic installations in ships – Electromagnetic
compatibility.
IEC 60684-2:2003, Flexible insulating sleeving – Part 2: Methods of test
Amendment 1 (2003)
IEC 60702-1:2002, Mineral insulated cables and their terminations with a rated voltage not
exceeding 750V
IEC 60702-2:2002, Mineral insulated cables and their terminations with a rated voltage not
exceeding 750 V – Terminations
IEC 60754-1:1994, Test on gases evolved during combustion of materials from cables –
Determination of the amount of halogen acid gas.
IEC 60754-2:1991 Test on gases evolved during combustion of electric cables –
Determination of degree of acidity of gases evolved during the combustion of materials taken
from electric cables by measuring pH and conductivity
Amendment 1 (1997)
IEC 61034-2:2005 Measurement of smoke density of cables burning under defined conditions
– Test procedure and requirements.
3 Types, construction, installation and operating conditions of cables
3.1 Types of cables
Cables constructed in accordance with IEC 60092-350, IEC 60092-353, IEC 60092-354, and
IEC 60092-376 are recommended for use on board ships. Cables (and their terminations) for
use in special applications which are constructed in accordance with IEC 60702-1 and IEC
60702-2 are also acceptable provided that due consideration has been given to their intended
application and use in a marine environment.

– 10 – 60092-352  IEC:2005(E)
3.2 Voltage rating
3.2.1 Power cables
The maximum rated voltage (U) considered in this standard for power cables is 15 kV.
In the voltage designation of cables U / U / (U ):
0 m
U is the rated power voltage between conductor and earth or 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
m
normal operating conditions at anytime and at any point in the system. It excludes
transient voltage conditions and rapid disconnection of loads.
U is chosen to be equal to or greater than the highest voltage of the three-phase system.
m
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 maximum system
voltage (U ) of the cable.
m
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 in contact
with earth or an earth conductor is automatically disconnected from the system.
• Category B
This category comprises those systems that under fault conditions are operated for a short
time, not exceeding 8 h on any single 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.
NOTE 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 is not permitted to exceed 125 h.
• Category C
This category comprises all systems that do not fall into Categories A and B.
The nominal system voltages from 1,8/3 kV to 8,7/15 kV shown in Table 1 are generally in
accordance with Series I in IEC 60038. For nominal system voltages intermediate between
these standard voltages and also between 0,6/1 kV and 1,8/3 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 6 kV system, the cable is to have a rated voltage not less
than 6/10 kV.
60092-352  IEC:2005(E) – 11 –
A d.c. voltage to earth of up to a maximum of 1,5 times the a.c. U voltage may be used.
However, consideration should be given to the peak value when determining the voltage of
d.c. systems derived from rectifiers, bearing in mind that smoothing does not modify the peak
value when the semiconductors are operating on an open circuit.
Table 1 – Choice of cables for a.c. systems
System voltage System category Minimum rated voltage of cable U /U
o
Nominal voltage Maximum sustained Unscreened Single-core or
U voltage, U screened
m
kV kV kV kV
up to 0,25 0,3 A, B or C 0,15/0,25 -
1,0 1,2 A, B or C 0,6/1,0 0,6/1,0
3,0 3,6 A or B 1,8/3,0 1,8/3,0
3,0 3,6 C — 3,6/6,0
6,0 7,2 A or B 3,6/6,0
6,0 7,2 C — 6,0/10,0
10,0 12,0 A or B — 6,0/10,0
10,0 12,0 C — 8,7/15,0
15,0 17,5 A or B — 8,7/15,0
3.2.2 Control and instrumentation cables
The maximum rated voltage (U) for control and instrumentation cables considered in this
standard is 250 V.
In some instances for conductor sizes 1,5 mm and larger, or when circuits are to be supplied
from a low impedance source, 0,6/1 kV rated cables are specified for use as control or
instrumentation cables.
NOTE The use of 1,0 mm is under consideration for 0,6/1 kV applications.
3.3 Cross-sectional areas of conductors and current carrying capacities
3.3.1 Cross-sectional areas of conductors
The cross-sectional area of each conductor shall be selected to be large enough to comply
with the following conditions.
− The highest load to be carried by the cable shall be calculated from the load demands and
diversity factors.
− The “corrected current rating” calculated by applying the appropriate correction factors to
the “current rating for continuous services” shall not be lower than the highest current
likely to be carried by the cable. The correction factors to be applied are those given in
3.3.4, 3.3.5 and 3.3.6.
− The voltage drop in the circuit shall not exceed the limits specified by the regulatory body
for the circuits concerned – further guidance is given in 3.4.
− The cross-sectional area of the conductor shall be able to accommodate the mechanical
and thermal effects of a short circuit current (see 3.8) and the effects upon voltage drop of
motor starting currents (see Note 3 of 3.4).
− Class 5 conductors, where used, shall be subject to special consideration in respect of
maximum current-carrying capacity. Class 5 conductors have, in most cases, a lower
conductivity than the equivalent class 2 conductors of the same nominal cross-section.

– 12 – 60092-352  IEC:2005(E)
− The nominal cross-sections of the earth conductor shall comply with Table 2. One of the
alternative methods of determining the cross sectional area of each earthing conductor is
that based upon the rating of the fuse or circuit protection device installed to protect the
circuit. If this method is used, the nominal cross sectional area finally selected shall be the
higher of any cross sectional areas determined by each of the methods.
a
Table 2 – Sizes of earth continuity conductors and equipment earthing connections
Arrangement of earth conductor Cross-section Q of Minimum cross-section of
associated current earth conductor
carrying conductor
(One phase or
pole)
mm²
1. i) Insulated earth conductor in cable for fixed Q ≤ 16 Q
installation.
ii) Copper braid of cable for fixed installation
according to 8.2 of IEC 60092-350.
iii) Separate, insulated earth conductor for fixed
50 % of the current-carrying
installation in pipes in dry accommodation spaces,
Q > 16 conductor, but not less than
when carried in the same pipe as the supply cable.
16 mm²
Iv) Separate, insulated earth conductor when installed
inside enclosures or behind covers or panels,
including earth conductor for hinged doors as
specified in IEC 60092-203.
2. Uninsulated earth conductor in cable for fixed Q ≤ 2,5 1 mm
installation, armour or copper braid and in metal-to-
2,5 < Q 1,5 mm
metal contact with this.
≤ 6
Q > 6 Not permitted
3. Separately installed earth conductor for fixed Q < 2,5 Same as current-carrying
installation other than specified in 1 iii) and 1 iv). conductor subject to min.
1,5 mm² for stranded earthing
connection or 2,5 mm² for
unstranded earthing
connection
2,5 < Q ≤ 120 50 % of current-carrying
conductor, but not less than
4 mm²
Q > 120 70 mm
4. Insulated earth conductor in flexible cable. Q ≤ 16 Same as current-carrying
conductor
Q > 16 50 % of current-carrying
conductor, but minimum
16 mm
NOTE Refer also to 3.3.1 for a method based on the rating of fuses.
a
The term protective conductor is accepted as an alternative term for the earth continuity conductor.

3.3.2 Current carrying capacities
The procedure for cable selection employs rating factors to adjust the current carrying
capacities for different ambient temperatures, for the mutual heating effects of grouping with
other cables, methods of installation and short time duty. Guidance on the use of these
factors is given below.
60092-352  IEC:2005(E) – 13 –
3.3.3 Current ratings for continuous service
Continuous service for a cable is to be considered, for the purpose of this standard, as a
current-carrying service with constant load and having a duration longer than three times the
thermal time constant of the cable, i.e., longer than the critical duration (see Figure 2).
The current to be carried by any conductor for sustained periods during normal operation shall
be such that the appropriate conductor temperature limit is not exceeded.
The value shall either be:
– selected from one of the following annexes in accordance with the appropriate installation
method:
Annex A: a method for determination of current carrying capacities based upon those that
have been accepted and established in other applications of cable use. This method has
been derived from a technical basis established from experimental data on a number of
cables and installation information. It allows for greater choice of use in different
installation configurations. For further reference see IEC 60364-5-52.
The basis of the determination is on the following formula:
m n
I = A × S – B × S
where
I is the current carrying capacity (A);
S is the nominal cross-sectional area of conductor (mm );
A and B are coefficients, m and n are exponents according to cable type and method of
installation.
Values calculated using the above for various installations are given in Annex A together
with guidance on selection.
Annex B: a method for the determination of current carrying capacities as given in the
second edition (1997) of IEC 60092-352. The values were initially established in 1958
based on limited experimental data and have been both amended and their range
extended in attempts to reflect the changes in construction of cables and their maximum
conductor operating temperatures which have taken place. They are only valid for a
limited number of installations under certain conditions. It is recommended that they are
only used for refurbishment of ships or in conjunction with other guidance information.
The formula on which they are based is:
0,625
I = α. A
where
I is the current carrying capacity (A);
A is the nominal cross-sectional area of conductor (mm );
α is a coefficient related to the maximum permissible service temperature of the
conductor.
Values calculated using the above – given in Annex B – are only applicable when used in
accordance with the basis as given;
– or be determined using one of the following methods:
– as described by IEC 60287,or
– by calculation using a recognised method provided that the method is stated,
and where appropriate, account shall be taken of the characteristics of the load.
The selection of the method applicable to any particular installation is the responsibility of the
appropriate approval authority or governing regulation.

– 14 – 60092-352  IEC:2005(E)
3.3.4 Correction factors for different ambient air temperatures.
The current-carrying capacities tabulated in Annexes A and B assume a reference ambient air
temperature of 45 °C. This temperature is generally applicable to insulated conductors and
cables in any kind of ship and for navigation in any climate, irrespective of the method of
installation.
Where the ambient temperature in the intended location of the insulated conductors or cables
differs from the reference ambient temperature, the appropriate correction factor specified in
Table 3 shall be applied to the values of current-carrying capacity set out in Annexes A and B
NOTE The air temperature around the cables can be higher than 45 °C when, for instance, a cable is wholly or
partly installed in spaces or compartments where heat is produced or due to heat transfer.
The correction factors in Table 3 do not take account of the increase in temperature, if any,
due to solar or other infrared radiation. Where the cables or insulated conductors are subject
to such radiation, the current-carrying capacity shall be derived by the methods specified in
IEC 60287.
Table 3 – Correction factor for various ambient air temperatures
(Reference ambient temperature of 45 °C)
Maximum Correction factors for ambient air temperature of
rated
conductor
temperature
35 °C 40 °C 45 °C 50 °C 55 °C 60 °C 65 °C 70 °C 75 °C 80 °C 85 °C
°C
60 1,29 1,15 1,00 0,82 - - - - - - -
65 1,22 1,12 1,00 0,87 0,71 - - - - - -
70 1,18 1,10 1,00 0,89 0,77 0,63 - - - - -
75 1,15 1,08 1,00 0,91 0,82 0,71 0,58 - - - -
80 1,13 1,07 1,00 0,93 0,85 0,76 0,65 0,53 - - -
85 1,12 1,06 1,00 0,94 0,87 0,79 0,71 0,61 0,50 - -
90 1,10 1,05 1,00 0,94 0,88 0,82 0,74 0,67 0,58 0,47 -
95 1,10 1,05 1,00 0,95 0,89 0,84 0,77 0,71 0,63 0,55 0,45

3.3.5 Correction factors for short time duty
If a cable is intended to supply a single motor or equipment operating for periods of half an
hour or one hour, its current rating, as given in the relevant table (see Annexes A and B), may
be increased using the relevant correction factors obtained from Figure 1. These correction
factors are only applicable if the intermediate periods of rests are longer than the critical
duration (which is equal to three times the time constant of the cable), obtained from Figure 2,
as a function of the cable diameter.
NOTE 1 The correction factors given in Figure 1 are approximate and depend mainly upon the diameter of the
cable. In general, the half-an-hour service is applicable to mooring winches, windlasses, heavy cargo winches and
bowthrusters. The half-an-hour rating might not be adequate for automatic tensioning mooring winches and
bowthrusters of specialised vessels.
NOTE 2 For cables supplying a single motor or other equipment intended to operate in an intermittent service, as
is generally the case for cargo winches (except heavy cargo winches), engine room cranes and similar devices, the
current ratings as given in Annexes A and B may be increased by applying the correction factor obtained from
Figure 3.
NOTE 3 The correction factor given in Figure 3 has been calculated for periods of 10 min, of which 4 min are with
a constant load and 6 min without load.

60092-352  IEC:2005(E) – 15 –
3.3.6 Correction Factors for Cable Grouping
In the case of a group of insulated conductors or cables the current carrying capacities
tabulated are subjected to the group correction factors given in the relevant annex.
The group correction factors are applicable to groups of insulated conductors or cables having
the same maximum operating temperature.
For groups containing cables or insulated conductors having different maximum operating
temperatures, the current carrying capacity of all the cables or insulated conductors in the
group shall be based on that of the lowest maximum rated conductor temperature of any cable
in the group together with the appropriate group correction factor.
Where operating conditions are known, and a cable or insulated conductor is not expected to
carry a current greater than 30 % of its calculated grouped rating, it can be ignored for the
purpose of obtaining a correction factor for the rest of the group. Also in the case of cables
not being loaded simultaneously, consideration of the actual loading appertaining is permitted.
NOTE Cables are said to be bunched when two or more are contained within a single conduit, trunking or duct, or,
if not enclosed, are not separated from each other.
3.4 Voltage drop
In the absence of specific design limits or limits set by a regulatory body, the cross-sectional
areas of conductors shall be so determined that when the conductors are carrying the
maximum current under normal conditions of service, the drop in voltage from the main or
emergency switchboard bus-bars to any and every point on the installation does not exceed
the limitation given in Clause 36 of IEC 60092-201.
NOTE 1 For supplies from batteries with a voltage not exceeding 50 V, the maximum permitted value of the
voltage drop may be increased by 10 %.
NOTE 2 For navigation lights it may be necessary to limit voltage drops to lower values in order to maintain
required lighting output and colour.
NOTE 3 The values of voltage drop are applicable under normal steady conditions. Under special conditions of
short duration, such as motor starting, higher voltage drops may be accepted provided the installation is capable of
withstanding the effects of these higher transient voltage drops or dips.
3.5 Estimation of lighting loads
For the purpose of determining sizes of conductors in lighting circuits, the assessment of the
current to be carried shall be made on the basis that every lampholder is deemed to require a
current equivalent to the maximum load likely to be connected to it. This shall be assumed to
be at least 100 W; except that, where the lighting fitting is so constructed so as to only take a
lamp rated at less than 100 W, the current rating shall be assessed accordingly.
Each lighting socket-outlet will count for two lighting points.
3.6 Parallel connection of cables
The current carrying capacity of cables connected in parallel is the sum of the current ratings
of all parallel conductors but the cables must have equal impedance, equal cross-section,
equal maximum permissible conductor temperatures and follow substantially identical routing
or be installed in close proximity. Connections in parallel are only permitted for cross-sections
of 10 mm or above. When equal impedance can not be assured, a correction factor of 0,9
shall be applied to the current carrying capacity.

– 16 – 60092-352  IEC:2005(E)
3.7 Separation of circuits
Separate cables are to be used for all circuits requiring individual short-circuit or overcurrent
protection, with the exception of the following:
-A control circuit which is branched off from its main circuit (e.g. for an electric motor) may be
carried in the same cable as the main circuit provided the main circuit and the subsidiary
contr
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