IEC 60092-503:2007

INTERNATIONAL IEC
STANDARD 60092-503
Second edition
2007-06
Electrical installations in ships –
Part 503:
Special features –
AC supply systems with voltages in the range
of above 1 kV up to and including 15 kV
Reference number
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INTERNATIONAL IEC
STANDARD 60092-503
Second edition
2007-06
Electrical installations in ships –
Part 503:
Special features –
AC supply systems with voltages in the range
of above 1 kV up to and including 15 kV
PRICE CODE
Commission Electrotechnique Internationale R
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 60092-503 © IEC:2007(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative references .7
3 Terms and definitions .8
3.1 AC voltages.8
3.2 Earthed neutral systems.9
3.3 Insulation .9
4 General requirements .9
4.1 Voltage and frequency.9
4.2 Warning notices .10
4.3 Access .10
4.4 Insulation level .10
4.5 Clearances and creepage distances .10
4.5.1 Clearance distance.10
4.5.2 Creepage distance .10
4.6 Earthing .11
4.7 Distribution systems .12
4.7.1 Divided system .12
4.7.2 Auxiliary circuits .12
4.7.3 Busbars of main switchboards .12
4.7.4 Generator circuits .13
4.7.5 Outgoing circuits .13
4.7.6 Power-transformer circuits.13
4.7.7 Shore-connection circuits and circuits to other units .13
4.7.8 Control and instrumentation circuits.13
4.8 Generator and transformer neutrals.13
4.8.1 Generator neutrals interconnected.13
4.8.2 Disconnection.14
4.9 Electrical protection.14
4.9.1 General .14
4.9.2 Generator protection.14
4.9.3 Motor protection .14
4.9.4 Power-transformer protection .14
4.9.5 Voltage-transformer protection .14
4.9.6 Overvoltage protection .14
4.9.7 Earth-fault monitoring .14
5 Equipment .15
5.1 AC generators and motors.15
5.1.1 Enclosures .15
5.1.2 Performance.15
5.1.3 De-excitation .16
5.1.4 Mechanical characteristics.16
5.2 Transformers.16
5.2.1 Enclosures and installations .16

60092-503 © IEC:2007(E) – 3 –
5.2.2 Accumulation of moisture and condensation .16
5.2.3 Transient voltage conditions .17
5.2.4 Current inrush .17
5.3 Switchgear and controlgear assemblies (switchboards) .17
5.3.1 Design and construction .17
5.3.2 Passageways .18
5.4 Switchgear and controlgear and fuses .18
5.5 Cables.18
5.5.1 General .18
5.5.2 Installation.18
5.5.3 Conductors and terminations .18
5.5.4 Current rating .19
5.5.5 Testing .19
5.5.6 Socket-outlets .19

Table 1 – AC three-phase systems having a nominal voltage above 1 kV and up to
and including 15 kV .9
Table 2 – Minimum clearance for equipment .10
Table 3 – Minimum creepage distances for main switchboards and generators .11
Table 4 – Minimum creepage distances for other equipment .11

– 4 – 60092-503 © IEC:2007(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
______________
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 503: Special features –
AC supply systems with voltages in the range
of above 1 kV up to and including 15 kV

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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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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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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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 60092-503 has been prepared by IEC technical committee 18:
Electrical installations of ships and of mobile and offshore units
This second edition cancels and replaces the first edition published in 1975. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition.
a) The scope is changed to an upper limit of the system voltage from 11 kV to 15 kV.
b) General requirements regarding warning notices, access to installations, clearances and
creepage distances of uninsulated conductors and earthing have been introduced.
c) Technical review has generally been made to update the standard according to general
requirements and referenced equipment standards.

60092-503 © IEC:2007(E) – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
18/1053/FDIS 18/1059/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 60092 series, under the general title Electrical installations in
ships, 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.
A bilingual version of this publication may be issued at a later date.

– 6 – 60092-503 © IEC:2007(E)
INTRODUCTION
IEC 60092 forms a series of International Standards for electrical installations in sea-going
ships, incorporating good practice and coordinating, as far as possible, existing rules.
These standards form a code of practical interpretation and amplification of the requirements
of the International Convention for the Safety of Life at Sea, a guide for future regulations
which may be prepared, and a statement of practice for use by shipowners, shipbuilders and
appropriate organizations.
60092-503 © IEC:2007(E) – 7 –
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 503: Special features –
AC supply systems with voltages in the range
of above 1 kV up to and including 15 kV

1 Scope
This part of IEC 60092 is applicable to a.c. supply systems with voltages from 1 kV up to and
including 15 kV. The requirements contained in other parts of IEC 60092 apply where
appropriate, subject to the exceptions stated in the following clauses.
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 60034 (all parts), Rotating electrical machines
IEC 60038:1983, IEC standard voltages
IEC 60071-1, Insulation co-ordination – Part 1: Definitions, principles and rules
IEC 60071-2, Insulation co-ordination – Part 2: Application guide
IEC 60076 (all parts), Power transformers
IEC 60092-201, Electrical installations in ships – Part 201: System design – General
IEC 60092-202, Electrical installations in ships – Part 202: System design – Protection
IEC 60092-350, Electrical installations in ships – Part 350: Shipboard power cables – General
construction and test requirements
IEC 60092-353, 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
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)
IEC 60265-1, High-voltage switches – Part 1: Switches for rated voltages above 1 kV and less
than 52 kV
IEC 60282-1:2005, High-voltage fuses – Part 1: Current-limiting fuses
IEC 60502 (all parts), Power cables with extruded insulation and their accessories for rated
voltages from 1 kV (U = 1,2 kV) up to 30 kV (U = 36 kV)
m m
– 8 – 60092-503 © IEC:2007(E)
IEC 60502-1, Power cables with extruded insulation and their accessories for rated voltages
from 1 kV (U = 1,2 kV) up to 30 kV (U = 36 kV) – Part 1: Cables for rated voltages of 1 kV
m m
(U = 1,2 kV) up to 3 kV (U = 3,6 kV)
m m
IEC 60502-2, Power cables with extruded insulation and their accessories for rated voltages
from 1 kV (U = 1,2 kV) up to 30 kV (U = 36 kV) – Part 2: Cables for rated voltages from
m m
6 kV (U = 7,2 kV) up to 30 kV (U = 36 kV)
m m
IEC 60694:1996, Common specifications for high-voltage switchgear and controlgear
standards
IEC 62271(all parts), High-voltage switchgear and controlgear
IEC 62271-200:2003, High-voltage switchgear and controlgear – Part 200: AC metal-enclosed
switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 AC voltages
For alternating voltages, the voltages stated below are r.m.s. values.
3.1.1
nominal system voltage
voltage by which a system is designated
[IEC 60038, Clause 1]
3.1.2
highest and lowest voltages of a system (excluding transient or abnormal conditions)
3.1.2.1
highest voltage of a system
highest value of voltage which occurs under normal operating conditions at any time and at
any point on the system
NOTE It excludes voltage transients, such as those due to system switching and temporary voltage variations.
[IEC 60038, 2.1, modified]
3.1.2.2
lowest voltage of a system
lowest value of voltage which occurs under normal operating conditions at any time and at
any point on the system
NOTE It excludes voltage transients, such as those due to system switching and temporary voltage variations.
[IEC 60038, 2.2, modified]
3.1.2.3
highest voltage for equipment
maximum value of the "highest system voltage" (see 3.1.2.1) for which the equipment may be
used
NOTE Attention is drawn to the fact that in some equipment standards the term "voltage range" has a different
meaning.
60092-503 © IEC:2007(E) – 9 –
[IEC 60038, Clause 9, modified]
3.2 Earthed neutral systems
3.2.1
high-resistance earthed neutral
system where the neutral is earthed through a resistance with numerical value equal to, or
somewhat less than, one-third of the capacitive reactance between phase and earth
3.2.2
low-resistance earthed neutral
system where the neutral is earthed through a resistance which limits the earth fault current to
a minimum value of 20 % and a maximum value of 100 % of the rated current of the largest
generator
3.3 Insulation
3.3.1
insulation coordination
selection of the dielectric strength of equipment in relation to the voltages which can appear
on the system for which the equipment is intended and taking into account the service
environment and the characteristics of the available protective devices
[IEC 60071-1, 3.1]
3.3.2
rated insulation level
set of rated withstand voltages which characterize the dielectric strength of the insulation
[IEC 60071-1, 3.35]
4 General requirements
4.1 Voltage and frequency
Voltage and frequency shall be chosen in accordance with IEC 60038. The maximum nominal
system voltage is 15 kV. The preferred values for ship supply systems are stated in Table 1.
Table 1 – AC three-phase systems having a nominal voltage
above 1 kV and up to and including 15 kV
a
Nominal frequency Highest voltage for
Nominal system voltage
equipment
Hz
kV
kV
3 3,6
3,3 3,6
6 7,2
6,6 50 or 60 7,2
10 12
11 12
15 17,5
a
The values are voltages between phases.

– 10 – 60092-503 © IEC:2007(E)
4.2 Warning notices
Warning notices shall be fixed in a visible position:
− both inside high-voltage rooms and at the entrance; and
− on high-voltage equipment.
4.3 Access
Live parts of the installation shall have an earthed screen, earthed enclosure or approved
insulation by the appropriate authority.
Live parts, which are to be operated or examined, shall be located and protected in such a
way that they can be operated or examined easily and without danger.
4.4 Insulation level
The conditions on board ships may require certain equipment having an insulation level
higher than that of the nominal voltage of the system, see IEC 60071-1 and IEC 60071-2. This
shall be agreed between the manufacturer and the purchaser.
4.5 Clearances and creepage distances
4.5.1 Clearance distance
Uninsulated conductors which are not earthed shall be installed with a clearance from one
another and from other conductive objects and from walls, ceilings or their own protective
covers of at least 5 cm + 0,5 cm for each 1 kV of operating voltage, unless voltage tests
carried
...