kSIST FprEN ISO 16315:2025

SLOVENSKI STANDARD
oSIST prEN ISO 16315:2024
01-februar-2024
Mala plovila - Električni sistemi za električni pogon (ISO/DIS 16315:2023)
Small craft - Electrical systems used for electrical propulsion (ISO/DIS 16315:2023)
Kleine Wasserfahrzeuge - Elektrische Antriebssysteme (ISO/DIS 16315:2023)
Petits navires - Systèmes électriques utilisés pour la propulsion électrique (ISO/DIS
16315:2023)
Ta slovenski standard je istoveten z: prEN ISO 16315
ICS:
47.020.60 Električna oprema ladij in Electrical equipment of ships
konstrukcij na morju and of marine structures
47.080 Čolni Small craft
oSIST prEN ISO 16315:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 16315:2024
oSIST prEN ISO 16315:2024
DRAFT INTERNATIONAL STANDARD
ISO/DIS 16315
ISO/TC 188 Secretariat: SIS
Voting begins on: Voting terminates on:
2023-12-07 2024-02-29
Small craft — Electrical systems used for electrical
propulsion
ICS: 47.080
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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NATIONAL REGULATIONS.
ISO/DIS 16315:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 16315
ISO/TC 188 Secretariat: SIS
Voting begins on: Voting terminates on:

Small craft — Electrical systems used for electrical
propulsion
ICS: 47.080
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 16315:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
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TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 5
4.1 General . 5
4.2 Components of an electric propulsion system . 6
4.3 Electric propulsion systems . 6
4.4 Arrangements for other electrical equipment and circuits on-board a small craft
connected to a common energy source for both propulsion and general electrical
installation . 8
4.4.1 DC systems . . 8
4.4.2 AC systems . 8
4.5 Environmental factors . 9
4.6 Electrical ratings . 9
4.7 Equipment . 10
4.7.1 Transformers . 10
4.7.2 Converters . 10
4.7.3 Motors . 10
4.8 Enclosures. 10
4.9 Identification of equipment and conductors . 11
4.10 Segregation of DC and AC systems. 11
4.11 Steering and throttle controls . 11
4.12 Electromagnetic compatibility (EMC) .12
4.13 Electrical equipment in the vicinity of battery banks .12
4.14 Hazardous areas .12
5 Controls, monitoring, system alerts and trips alarms .13
5.1 Electrical/electronic controls for electric propulsion systems .13
5.1.1 Controls . 13
5.1.2 Emergency stop . 13
5.1.3 Fault trip reset . 13
5.2 Instruments, alerts and trip alarms . 14
5.2.1 General . 14
5.2.2 Operating mode and status . 14
5.2.3 System alerts . 14
5.2.4 Fault trip alarms . 14
6 Protection against electric shock .15
6.1 Protection against direct contact . 15
6.2 Automatic disconnection of supply to the electric propulsion system under
fault-to-earth conditions (earthed two wire DC systems and earthed neutral AC
systems) . 15
6.3 Fault-to-earth monitoring and tripping arrangements for DC fully insulated
systems, DC 3-wire systems . 16
6.4 Fault-to-earth tripping in AC non-neutral earthed systems (IT-type system) . 16
7 Protection against over-current .17
7.1 General . 17
7.2 Characteristics of protective devices . 17
7.3 Overcurrent devices in the outgoing circuit(s) from a battery . 17
8 Battery monitoring and installation .17
8.1 General arrangements . 18
iii
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
8.2 Isolation of battery packs or battery banks . 18
8.3 Operational switching of battery pack(s) or battery bank(s) . 19
8.4 Permanently energized circuits . 19
8.5 Ventilation . 19
8.6 Electrical apparatus for explosive gas atmospheres . 20
9 Electrical installation .20
9.1 General . 20
9.2 Segregation of electrical propulsion system cables . 20
10 Testing.20
10.1 General . 20
10.2 Earthing and bonding. 21
10.3 Insulation resistance. 21
10.3.1 General . 21
10.3.2 DC electrical propulsion systems . 21
10.3.3 AC electrical propulsion systems . 21
10.3.4 Switchboards, panel boards and distribution boards . 21
10.3.5 Power and lighting final circuits . 21
10.3.6 Generators and motors . 22
10.3.7 Transformers .22
10.4 Electrical/electronic controls systems for propulsion motor control .22
10.5 On load test and inspection of electrical propulsion systems, and associated
switch gear and control gear .22
10.6 Voltage drop . 22
Annex A (normative) Information and instructions to be included in the owner's manual .23
Annex B (normative) Installation documentation .24
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2013/53/EU aimed to be covered.25
Bibliography .28
iv
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 188, Small craft, together with CEN/
TC 464, Small craft and IEC/TC 18, Electrical installations of ships and of mobile and fixed offshore units.
This second edition cancels and replaces the first edition (ISO 16315:2016), which has been technically
revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
Introduction
Electrical propulsion systems are becoming more common in recreational craft and other small craft
and propulsion system voltages of up to AC 1 000 V and DC 1 500 V are possible together with variable
speed drives operating at frequencies which differ from 50/60 Hz or DC.
Electric propulsion systems for small craft are generally designed and constructed from a number of
component parts many of which can be of proprietary origin and all of the electrical and control items
are interconnected by cables and operated as a system.
A propulsion system designer/installer should be competent with all components of the system
addressed by this standard, as well as all aspects of any other equipment included in the design of a
system such that the component parts of the propulsion system are integrated in a complete and safe
manner.
There are a significant number of electrical propulsion system architectures for small craft and the
main types are the following.
— DC sourced. The main power source is a propulsion battery which is either recharged from on-
board DC generators, or on-board AC generators/an AC shore supply through battery chargers. The
electric propulsion system(s) can be variable speed through a DC motor controller or AC through a
Variable Frequency Drive (VFD) or be fixed speed with a variable pitch propeller or other mechanical
means of providing thrust. The electric propulsion system can be electrically separate from other
electrical systems on board (e.g. be fully insulated via the motor controller, or be an AC IT system via
a VFD or motor starter). Or the electrical propulsion system can be integrated with the whole craft
DC electrical system using converters DC/DC, DC/AC to provide for different services/consumers.
— AC sourced. The main power source is AC generator(s). The electric propulsion system(s) can be DC
variable speed through a AC/DC converter and DC motor controller, or AC through a VFD, or be fixed
speed with a variable pitch propeller or other mechanical means of providing thrust. The electric
propulsion system can be DC fully insulated system or be an AC IT system via a galvanically isolated
VFD or via an isolating transformer. A DC propulsion system(s) can be supported by propulsion
battery.
— Also possible are hybrid systems similar to the types being introduced for road vehicles where the
source is an internal combustion engine providing, for example, energy to a relatively lightweight
energy storage system with power take-off via converters to propulsion motor(s) and other electrical
consumers.
It is essential that the electric propulsion system designer/installer be competent with all aspects
of the equipment included in the design of a particular system such that the component parts of the
propulsion system are integrated in a coherent and safe manner.
Current electrical standards for small craft of less than 24 m LH are the following:
ISO 13297:2014 which covers extra-low-voltage direct current (DC) electrical systems that operate at
nominal potentials of 50 V DC or less and single-phase alternating current (AC) systems that operate at
a nominal voltage not exceeding AC 250 V.
This standard does not include requirements for electrical propulsion systems.
a) IEC 60092-507:2014 is applicable to small craft up to 50 m/500 GT and includes requirements for
three-phase systems not exceeding AC 500 V and single-phase systems not exceeding AC 250 V and
for DC systems and sub-systems not exceeding DC 50 V nominal, and includes a section on electric
propulsion systems.
vi
oSIST prEN ISO 16315:2024
DRAFT INTERNATIONAL STANDARD ISO/DIS 16315:2023(E)
Small craft — Electrical systems used for electrical
propulsion
1 Scope
This International Standard addresses the design and installation of alternating current (AC) and direct
current (DC) electrical systems used for the purpose of electrical propulsion and/or electrical hybrid
(system with both a rechargeable battery and a fuelled power source) propulsion.
This International Standard applies to electrical propulsion systems operated in the following ranges
either individually or in combination:
— direct current of less than 1 500 V DC;
— single-phase alternating current up to AC 1 000 V;
— three-phase alternating current up to AC 1 000 V.
This International Standard applies to electrical propulsion systems installed in small craft up to 24 m
length of the hull (L according to ISO 8666).
H
This International Standard also lists in Annex A additional information to be included in the owner's
manual as well as Annex B additional information to be provided to the installer.
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.
EN 55012:2007+A1 2009, Vehicles, Boats And Internal Combustion Engines. Radio Disturbance
Characteristics. Limits And Methods Of Measurement For The Protection Of Off-Board Receivers
EN 61000-1-1:2023, Electromagnetic compatibility (EMC) - Part 1-1: General - Application and
interpretation of fundamental definitions and terms
ISO 8846:1990, Small craft — Electrical devices — Protection against ignition of surrounding flammable
gases
ISO 9094:2015, Small craft — Fire protection
ISO 10133:2012, Small craft — Electrical systems — Extra-low-voltage d.c. installations
ISO 10239:2014, Small craft — Liquefied petroleum gas (LPG) systems
ISO 11105:2020, Small craft — Ventilation of petrol engine and/or petrol tank compartments
ISO 13297:2014, Small craft — Electrical systems — Alternating current installations
ISO 25197:2012, Small craft — Electrical/electronic control systems for steering, shift and throttle
IEC 60034-1:2017, Rotating electrical machines –Part 1: Rating and performance
IEC 60947:2020, Low-voltage switchgear and controlgear - Part 1: General rules
IEC 60079-7:2015, Electrical apparatus for explosive gas atmospheres, Part 7: Equipment protection by
increased safety “e”
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
IEC 60092-202:2016, Electrical installation in ships — Part 202: System design — Protection
IEC 60092-303:1980, Electrical installation in ships — Part 303: Equipment — Transformers for power and
lighting
IEC 60092-352:2005, Electrical installation in ships — Part 352: Choice and installation of electrical cables
IEC 60092-507:2014, Electrical installations in ships — Part 507: Small vessels
IEC 60533:2015, Electrical and electronic installations in ships – Electromagnetic compatibility (EMC) –
Ships with a metallic hull
IEC 60146-1-1:2009, Semiconductor Converters – General Requirements And Line Commutated Converters
– Part 1-1: Specification Of Basic Requirements
I EC 6 0 8 98 -1:2015/A M D1: 2019/ COR 1: 2020, Electrical accessories — Circuit-breakers for overcurrent
protection for household and similar installations — Part 1: Circuit-breakers for a.c. operation
IEC 60945:2002, Maritime navigation and radiocommunication equipment and systems — General
requirements — Methods of testing and required test results
IEC 60947-2:2019, Low voltage switchgear and control gear — Part 2: Circuit breakers
IEC 61558-2-4:2021, Safety of transformers, reactors, power supply units and similar products for supply
voltages up to 1 100 V — Part 2-4: Particular requirements and tests for isolating transformers and power
supply units incorporating isolating transformers
IEC 61558-2-6:2021, Safety of transformers, reactors, power supply units and similar products for supply
voltages up to 1 100 V — Part 2-6: Particular requirements and tests for safety isolating transformers and
power supply units incorporating safety isolating transformers
IEC 62742:2021, Electrical and electronic installations in ships – Electromagnetic compatibility (EMC) –
Ships with a non-metallic hull
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
safety voltage
voltage which does not exceed AC 50 V r.m.s. between conductors, or between any conductor and
earth, in a circuit isolated from the supply by means such as a safety isolating transformer, or converter
with separate winding voltage which does not exceed 50 DC V between conductors, or between
any conductor and earth, in a circuit which is isolated from higher voltage circuits
Note 1 to entry: Consideration should be given to the reduction of the limit of 50 V under certain conditions, such
as wet surroundings or exposure to heavy seas or where direct contact with live parts is involved.
Note 2 to entry: The voltage limit should not be exceeded either at full load or no load, but it is assumed, for the
purpose of this definition, that any transformer or converter is operated at its rated supply voltage.
[4]
[SOURCE: IEC 60092-101:2018, 1.3.19]
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
3.2
rated voltage
U
nominal AC r.m.s. line voltage to earth nominal AC r.m.s. voltage between
line conductor and neutral conductor nominal DC voltage between poles
[SOURCE: IEC 60092-507:2014, 3.1.4]
3.3
live part
conductor or conductive part intended to be energized in normal operation including a neutral
conductor, but by convention not a PEN conductor (a conductor combining the functions of both a
protective conductor and a neutral conductor)
Note 1 to entry: This term does not necessarily imply risk of electric shock.
[SOURCE: IEC 60050-195:1998, 195-02-19, modified as follows: The text “or a PEM conductor or PEL
conductor” has been deleted. The text in brackets has been added]
3.4
earthed
grounded, en US
connected to the general mass of the hull of the craft in such a manner as will ensure at all times an
immediate discharge of electrical energy without danger
[SOURCE: IEC 60092-101:2018, 1.3.9,]
3.5
readily accessible
capable of being reached quickly and safely for effective use without the use of tools
[SOURCE: ISO 13297:2014, 3.17]
3.6
final circuit
portion of a wiring system extending beyond the final overcurrent protection device for that circuit
[SOURCE: IEC 60092-101:2018, 1.3.17, modified – The words “overcurrent protective device of a board”
have been replaced with “overcurrent protection device for that circuit”]
3.7
overcurrent protection device
device provided to interrupt an electric circuit in case the conductor current in the electric circuit
exceeds a predetermined value for a specified duration
3.8
fuse
device that by the fusing of one or more of its specifically designed and proportioned components,
opens the circuit in which it is inserted by breaking the current when this exceeds a given value for a
sufficient time
Note 1 to entry: The fuse comprises all the parts that form the complete device.
[SOURCE: IEC 60050-441:1984, 441-18-01, modified]
3.9
circuit-breaker
mechanical switching device capable of making, carrying and breaking currents under normal circuit
conditions, and also making, carrying for a specified time and breaking currents under specified
abnormal circuit conditions such as those of a short circuit
[SOURCE: IEC 60050-441:1984, 441-14-20]
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
3.10
residual current device
RCD
mechanical switching device designed to make, carry and break currents under normal service
conditions and to cause the opening of the contacts when the residual current attains a given value
under specified conditions
[SOURCE: IEC 60050-442:1994, 442-05-02, modified as Note has been omitted]
3.11
protective conductor
PE (identification)
conductor provided for purposes of safety, for example, protection against electric shock
Note 1 to entry: In an electrical installation, the conductor identified PE is normally also considered as protective
earthing conductor.
[SOURCE: IEC 60050-195:1998, 195-02-09]
3.12
bond
connection of non-current-carrying parts to ensure continuity of electrical connection, or to equalize
the potential between parts comprising, for example, the armour or cable screen of adjacent length of
cable, the bulkhead, etc.
[SOURCE: IEC 60092-101:2018, 1.3.7, modified – Last part concerning “cables in a radio-receiving room”
has been deleted.]
3.13
conductor
conductive part intended to carry a specified electric current
[SOURCE: IEC 60050-195:1998, 195-01-07]
3.14
neutral conductor
conductor electrically connected to the neutral point and capable of contributing to the distribution of
electrical energy
[SOURCE: IEC 60050-195:1998, 195-02-06]
3.15
line conductor
phase conductor (in AC systems) (deprecated) pole conductor (in DC systems) (deprecated) conductor
which is energized in normal operation and capable of contributing to the transmission or distribution
of electric energy but which is not a neutral conductor
[SOURCE: IEC 60050-195:1998, 195-02-08]
3.16
transformer
energy converter with isolating separation between the input and output windings and the protective
conductor
3.17
switch
mechanical switching device capable of making, carrying and breaking currents under normal circuit
conditions which can include specified operating overload conditions and also carrying for a specified
time currents under specified abnormal circuit conditions such as those of short circuit
Note 1 to entry: A switch can be capable of making but not breaking short-circuit currents.
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
3.18
panel board
assembly of devices, such as circuit breakers, fuses, switches, instruments and indicators, for the
purpose of controlling and/or distributing electrical power
Note 1 to entry: Examples of devices include circuit breakers, fuses, switches, instruments and indicators.
3.19
disconnector
mechanical switching device which provides, in the open position, an isolating distance in accordance
with specified requirements
[SOURCE: IEC 60050-441:1994, 441-14-05]
3.20
battery pack
mechanical assembly comprising battery cells and retaining frames or trays and possibly components
for battery management
Note 1 to entry: Typical battery packs will be a single assembly, voltage and connection in an enclosure.
Note 2 to entry: Several connected battery packs form a battery bank.
[SOURCE: ISO 12405-2:2012, 3.2, modified by additional Note 1 and 2 to entry]
4 General requirements
4.1 General
Electric propulsion systems for small craft are generally designed and constructed from a number of
component parts many of which can be of proprietary origin and all of the electrical and control items
are interconnected by cables and operated as a system.
For electric propulsion systems and other electrical systems with rated nominal voltages in excess of
safety voltage, the precautions against the risk of electric shock shall be observed.
The electric propulsion system can be electrically separate from other electrical systems on board a
small craft.
Different types of AC electrical system include four-wire with neutral earthed, but without hull return
(TN-C), five-wire with neutral earthed, but without hull return (TN-S), and IT systems with their
particular requirements for earth leakage current monitoring, alarm and tripping systems.
DC electric propulsion systems can have large capacity battery bank(s) or pack(s) as the main power
source, and particular attention is required for the following:
a) ventilation requirements necessary for battery bank or battery pack compartments;
b) requirements for an overcurrent device and an isolation switch for each propulsion battery bank or
battery pack;
c) circuit protection requirements for permanently energised circuits supplied from a battery bank
or battery pack.
Electric propulsion circuits shall be designed to protect against the following:
— fire by the use of overcurrent protection, grounding/earthing, terminal protection and conductor
type and size;
— shock by the use of enclosures, conductor and terminal insulation, automatic disconnection and
grounding/earthing system protection as appropriate.
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
Electric propulsion circuits shall not interact with other circuits in such a way that circuits would fail to
operate as intended.
4.2 Components of an electric propulsion system
The electric propulsion system can include several sub-systems and components including, but not
limited to, the following:
— batteries;
— battery management systems;
— AC or DC generators;
— AC/DC, DC/DC, DC/AC, AC/AC converters, Variable Frequency Drives;
— electric propulsion motors;
— propulsion panel board;
— propulsion motor controls, monitoring, system alerts and trip alarms;
— transformers;
— conductors and cables;
— isolation switches (disconnectors), circuit breakers, contactors, fuses.
Each of these propulsion system components shall conform to the relevant ISO/IEC standard.
4.3 Electric propulsion systems
4.3.1 An electrical propulsion system can be
a) DC, sourced from battery(s) or DC generator(s) or AC/DC converters from an AC source, or
b) AC, sourced from alternator(s) or a DC/AC converter from a DC source [e.g. battery(s)].
The energy source(s) of an electric propulsion system can be reserved for this purpose and be electrically
separate from other electrical systems on board a craft, or all electrical systems on board a craft can
be directly connected to a common source but propulsion system(s) can have specific requirements for
electrical separation, earthing/bonding, conductor installation, etc. from the other items of electrical
equipment and circuits included in the overall design.
The rated voltage of an electric propulsion can be different from other electrical systems on-board a
craft and uses either AC or DC systems.
— For an AC propulsion system, it can be at variable frequency.
— For a DC propulsion system sourced from an AC system, the DC electrical propulsion system can
be obtained from an AC/DC converter with galvanic separation between input and output and
appropriate arrangements made at the output for fully insulated or negative earth propulsion
systems. Similarly, an earthed two wires propulsion system can be supplied from an insulated two
wires source via a DC/DC converter with galvanic separation and vice versa.
— For a DC propulsion system sourced from a DC system, the source shall have the same characteristics.
— DC systems shall be either earthed, or be fully insulated with particular requirements for insulation
resistance monitoring, alarm and tripping systems, (See section 6.3.1). For DC propulsion systems
operating at voltages greater than safety voltage, a three-wire system (e.g. DC +48 V/0/−48 V) can
be considered with the mid-point conductor earthed to limit prospective touch voltage.
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
— Systems can require attention to the treatment of the neutral earth, and also have specific
requirements in respect of earthing and bonding relative to the requirements of other electrical
systems on-board a craft.
4.3.2 A DC electrical propulsion system shall be configured as
a) fully insulated two-wire system for any system voltage ;or
b) two-wire system with negative earth/bonded for systems below 60 Volts or
c) a earth/bonded three wire system.
4.3.3 A single-phase AC electrical propulsion system shall be configured as
a) single-phase two wire insulated (IT), or
b) single-phase two-wire with earthed neutral (TT or TN-C without hull return); or system having
only one connection to the earth TT (when shore connected, or
c) single-phase three-wire with mid-point earthed, both neutral and protective conductor (PE)
earthed at the energy source without hull return (TN-S).
4.3.4 A three-phase electrical propulsion system shall be configured as
a) three-phase three-wire insulated (IT), or
b) three-phase four-wire with earthed neutral (TT or TN-C without hull return); or TT (when shore
connected), or
c) three-phase five-wire with mid-point earthed, both neutral and protective conductor (PE) earthed
at the energy source without hull return (TN-S).
If the AC propulsion system is required to be an IT from a TN source (or vice-versa), then an isolation
transformer conforming to IEC 61558-2-4:2021 (U up to AC 1 100 V, maximum rated output 25 kVA for
single phase, 40 kVA for three-phase) shall be used providing galvanic separation between primary and
secondary windings with appropriate arrangements being made at the secondary circuit(s).
If an AC 110 V single-phase propulsion system is required sourced from an IT or TN source and increased
safety is required, then a safety isolating transformer can be used conforming to IEC 61558-2-6,
reducing the prospective touch voltage. (Note that secondary winding centre tap is required to be
earthed).
An AC propulsion system can be sourced from a DC source via a DC/AC converter providing galvanic
separation between input and output allowing the AC propulsion system (single-phase or three-phase)
to be IT or TN as required. The DC/AC converter can also be variable frequency. Similarly, an AC/AC
converter can be used providing galvanic separation and allowing the propulsion system (single-phase
or three-phase) to be IT or TN as required. The AC/AC converter can also be variable frequency type
(variable frequency drive).
NOTE For craft with metallic hull, the large cross-section area of metal for earth return paths enables simple
method of earthing and bonding (TT, TN and IT systems) in which non-current-carrying parts can be bonded
direct to the hull of the craft.
A craft with a non-metallic hull requires to be provided with a protective conductor which can be
separate from the neutral conductor (TN-S) or not separate (TN-C).
oSIST prEN ISO 16315:2024
ISO/DIS 16315:2023(E)
4.4 Arrangements for other electrical equipment and circuits on-board a small craft
connected to a common energy source for both propulsion and general electrical
installation
4.4.1 DC systems
In DC systems, equipment and circuits can be connected to the same source as the propulsion system
as follows:
a) Where the DC propulsion system requires to be insulated from earth as in 4.3.2 a), other equipment
and circuits shall be directly connected to the common DC source(s) these other electrical
equipment and circuits shall also be fully insulated from earth (in this case, a common insulation
resistance monitoring system as specified in 6.3). Each item of electrical equipment or final circuit
connected shall be provided with an overcurrent/fault protection device in both positive and
negative connections;
b) If either the propulsion system or the other equipment is required to be fully insulated and the
other negatively earthed or vice versa (or is a three-wire system with centre earth), DC/DC
converters with galvanic separation between input and output can be used where the output(s) can
be configured to be fully insulated or negative earthed or earthed three-wire as appropriate. Each
propulsion system or item of electrical equipment or final circuit connected to a DC/DC converter
shall be provided with an overcurrent/fault protection device [circuit breaker or fuse(s)] and in the
case of fully insulated propulsion system or other equipment or final circuits, the protective device
shall trip both poles of the circuit feeding the equipment or circuits. The input circuit to each DC
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