IEC 60364-7-721:2017
(Main)Low-voltage electrical installations - Part 7-721: Requirements for special installations or locations - Electrical installations in caravans and motor caravans
Low-voltage electrical installations - Part 7-721: Requirements for special installations or locations - Electrical installations in caravans and motor caravans
IEC 60364-7-721:2017 lays down particular requirements applying to electrical circuits and equipment intended for the use of the caravan for habitation purposes. This new edition includes the following significant technical changes with respect to the previous edition:
- a minimum height of not less than 500 mm above the base of the cylinders is now required for cables passing through the gas cylinder compartment;
- it is now required that each independent installation shall be provided with its own main isolating switch which shall disconnect all live conductors and which shall be suitably placed in a readily accessible location in the caravan.
Installations électriques à basse tension - Partie 7-721: Exigences pour les installations ou emplacements spéciaux - Installations électriques dans les caravanes et caravanes à moteur
IEC 60364-7-721:2017 s’applique aux circuits et matériels électriques des caravanes destinées à des fins de logement. Elles ne s’appliquent pas aux circuits et matériels électriques destinés à la propulsion. Elles ne s’appliquent pas aux installations électriques intérieures des maisons d’habitation mobiles, des caravanes résidentielles fixes et des unités transportables.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) Une hauteur minimale supérieure ou égale à 500 mm au-dessus de la base des bombonnes est désormais exigée pour les câbles passant par le compartiment contenant la bombonne de gaz.
b) Il est désormais exigé que chaque installation indépendante soit fournie avec son dispositif général de sectionnement qui doit déconnecter tous les conducteurs actifs et qui doit être placé de façon appropriée et accessible dans la caravane.
c) La numérotation des articles relatifs aux mesures de protection non autorisées (obstacles, mise hors de portée, emplacements non conducteurs, liaison équipotentielle non reliée) a changé.
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IEC 60364-7-721 ®
Edition 2.0 2017-06
INTERNATIONAL
STANDARD
Low-voltage electrical installations –
Part 7-721: Requirements for special installations or locations – Electrical
installations in caravans and motor caravans
All rights reserved. Unless otherwise specified, 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
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IEC 60364-7-721 ®
Edition 2.0 2017-06
INTERNATIONAL
STANDARD
Low-voltage electrical installations –
Part 7-721: Requirements for special installations or locations – Electrical
installations in caravans and motor caravans
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.020; 91.140.50 ISBN 978-2-8322-4425-8
– 2 – IEC 60364-7-721:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
721 Electrical installations in caravans and motor caravans . 7
721.1 Scope . 7
721.2 Normative references . 7
721.3 Terms and definitions . 8
721.31 Purposes, supplies and structure . 8
721.313 Supplies . 8
721.4 Protection for safety . 9
721.41 Protection against electric shock . 9
721.411 Protective measure: automatic disconnection of supply . 9
721.413 Protective measure: electrical separation . 9
721.414 Protective measure: extra-low voltage provided by SELV and PELV . 9
721.415 Additional protection . 9
721.43 Protection against overcurrent . 10
721.5 Selection and erection of equipment . 10
721.51 Common rules . 10
721.510 Introduction . 10
721.512 Operational conditions and external influences . 10
721.514 Identification . 10
721.52 Wiring systems . 10
721.521 Types of wiring systems . 10
721.522 Selection and erection of wiring systems in relation to external
influences . 11
721.524 Cross-sectional areas of conductors . 11
721.526 Electrical connections . 11
721.528 Proximity of wiring systems to other services . 11
721.53 Isolation, switching and control . 12
721.536 Isolation and switching . 12
721.54 Earthing arrangements and protective conductors . 12
721.543 Protective conductors . 12
721.55 Other equipment . 12
Annex A (normative) Instructions for electricity supply . 14
Annex B (informative) Extra low-voltage DC installations . 15
Annex C (informative) Current-carrying capacities . 21
Annex D (informative) List of notes concerning certain countries . 24
Bibliography . 25
Figure C.721.1 – Graph for obtaining minimum cross-sectional area for conductors for
fixed wiring installations with a voltage drop of 0,8 V . 21
Figure C.721.2 – Graph for obtaining minimum cross-sectional area for conductors for
battery cable installations with a voltage drop of 0,3 V . 22
Table 721.1 – Cross-sectional areas of flexible cords and cables for caravan
connection . 13
Table B.721.1 – Functional allocation and cross-sectional areas of cores for caravan
connectors . 18
– 4 – IEC 60364-7-721:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 7-721: Requirements for special installations or locations –
Electrical installations in caravans and motor caravans
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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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 60364-7-721 has been prepared by IEC technical committee 64:
Electrical installations and protection against electrical shock.
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) A minimum height of not less than 500 mm above the base of the cylinders is now required
for cables passing through the gas cylinder compartment. Where cables have to run
through a compartment such cables shall be protected against mechanical damage by
installation within a continuous conduit or duct passing through the compartment
(721.528.3.1).
b) It is now required that each independent installation shall be provided with its own main
isolating switch which shall disconnect all live conductors and which shall be suitably
placed in a readily accessible location in the caravan.(721.536.2.1.1)
c) The clause numbers for the protective measures not permitted (obstacles, placing out of
reach, non-conducting locations and earth-free local equipotential bonding) have been
changed.
The text of this International Standard is based on the following documents:
FDIS Report on voting
64/2200/FDIS 64/2210/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 60364 series, published under the general title Low-voltage
electrical installations, can be found on the IEC website.
The reader's attention is drawn to the fact that Annex D lists all of the “in-some-country”
clauses on differing practices of a less permanent nature relating to the subject of this
standard.
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.
A bilingual version of this publication may be issued at a later date.
– 6 – IEC 60364-7-721:2017 © IEC 2017
INTRODUCTION
For the purpose of this part (IEC 60364-7-721) the requirements of the general Parts 1 to 6 of
IEC 60364 apply.
The IEC 60364-7-7XX parts of IEC 60364 contain particular requirements for special
installations or locations which are based on the requirements of the general parts of
IEC 60364 (IEC 60364-1 to IEC 60364-6). These IEC 60364-7-7XX parts are considered in
conjunction with the requirements of the general parts.
The particular requirements of this part of IEC 60364 supplement, modify or replace certain of
the requirements of the general parts of IEC 60364 being valid at the time of publication of
this part. The absence of reference to the exclusion of a part or a clause of a general part
means that the corresponding clauses of the general part are applicable (undated reference).
Requirements of other 7XX parts being relevant for installations covered by this part also
apply. This part may therefore also supplement, modify or replace certain of these
requirements valid at the time of publication of this part.
The clause numbering of this part follows the pattern and corresponding references of
IEC 60364. The numbers following the particular number of this part are those of the
corresponding parts, or clauses of the other parts of the IEC 60364 series, valid at the time of
publication of this part, as indicated in the normative references of this document (dated
reference).
If requirements or explanations additional to those of the other parts of the IEC 60364 series
are needed, the numbering of such items appears as 721.101, 721.102, 721.103 etc.
In the case where new or amended general parts with modified numbering were published
after this part was issued, the clause numbers referring to a general part in this 721 part may
no longer align with the latest edition of the general part. Dated references should be
observed.
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 7-721: Requirements for special installations or locations –
Electrical installations in caravans and motor caravans
721 Electrical installations in caravans and motor caravans
721.1 Scope
The particular requirements of this part of IEC 60364 apply to electrical installations in
caravans and motor caravans.
They apply to those electrical circuits and equipment intended for the use of the caravan for
habitation purposes.
They do not apply to those electrical circuits and equipment for automotive purposes.
They do not apply to the electrical installations of mobile homes, residential park homes and
transportable units.
NOTE 1 For mobile homes and residential park homes the general requirements apply.
NOTE 2 For transportable units see IEC 60364-7-717.
NOTE 3 For the purposes of this document, caravans and motor caravans are referred to as “caravans”
The particular requirements of some parts from the IEC 60364-7 series can also apply to such
installations in caravans, for example IEC 60364-7-701.
721.2 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 60038, IEC standard voltages
IEC 60309-2, Plugs, socket-outlets and couplers for industrial purposes – Part 2: Dimensional
interchangeability requirements for pin and contact-tube accessories
IEC 60332-1-2, 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 60947-2, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers
IEC 61008-1, Residual current operated circuit-breakers without integral overcurrent
protection for household and similar uses (RCCBs) – Part 1: General rules
IEC 61009-1, Residual current operated circuit-breakers with integral overcurrent protection
for household and similar uses (RCBOs) – Part 1: General rules
IEC 61084 (all parts), Cables trunking and ducting systems for electrical installations
– 8 – IEC 60364-7-721:2017 © IEC 2017
IEC 61386 (all parts), Conduit systems for cable management
IEC 62423, Type F and Type B residual current operated circuit-breakers with and without
integral overcurrent protection for household and similar uses
721.3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
721.3.1
leisure accommodation vehicle
unit of living accommodation for temporary or seasonal occupation that may meet the
requirements for the construction and use of road vehicles
721.3.1.1
caravan
trailer leisure accommodation vehicle, used for touring, that meets the requirements for the
construction and use of road vehicles
721.3.1.2
motor caravan
self-propelled leisure accommodation vehicle, used for touring, that meets the requirements
for the construction and use of road vehicles
Note 1 to entry: A motor caravan is either adapted from a series production vehicle, or designed and built on an
existing chassis, with or without the driving cab, the accommodation being either fixed or dismountable.
721.3.1.3
mobile home
transportable leisure accommodation vehicle that includes means for mobility but does not
meet the requirements for the construction and use of road vehicles
721.3.1.4
residential park home
factory produced relocatable dwelling
721.31 Purposes, supplies and structure
721.313 Supplies
721.313.1 General
721.313.1.101 The nominal supply system voltage shall be selected from IEC 60038.
The nominal AC supply voltage of the installation of the caravan shall not exceed 230 V
single-phase, or 400 V three-phase.
The nominal DC supply voltage of the installation of the caravan shall not exceed 48 V.
721.4 Protection for safety
721.41 Protection against electric shock
721.410.3.5
Add the following:
The protective measures of obstacles and placing out of reach as specified in Annex B of
IEC 60364-4-41:2005 shall not be used.
721.410.3.6
Add the following:
The protective measures of non-conducting locations and earth-free local equipotential
bonding as specified in Annex C of IEC 60364-4-41:2005 shall not be used.
NOTE This precludes the use of class 0 equipment.
721.411 Protective measure: automatic disconnection of supply
721.411.3.1.2 Protective equipotential bonding
Metal frame parts or thereto connected construction parts shall be connected through main
protective bonding conductors to the main earthing terminal within the caravan.
721.413 Protective measure: electrical separation
The protective measure: electrical separation shall not be used, except for a shaver socket-
outlet.
721.414 Protective measure: extra-low voltage provided by SELV and PELV
Any part of a caravan installation operating at extra-low voltage shall comply with the
requirements of Clause 414.
For extra-low voltage DC power sources, a maximum of 48 V are allowed. In exceptional
cases, when AC extra-low voltage is required, the voltage (rms) is not allowed to exceed
48 V.
The requirements of Part 721 are also applicable to extra low-voltage DC installation. See
Annex B for recommendations that can be applied in addition.
721.415 Additional protection
721.415.101 Additional protection: residual current protective devices (RCDs)
Addition:
Where protection by automatic disconnection of supply is used, a residual current device with
a rated residual operating current not exceeding 30 mA, complying with IEC 60947-2,
IEC 61008-1, IEC 61009-1 or IEC 62423 breaking all live conductors, shall be provided. Each
supply inlet shall be directly connected to its associated RCD.
NOTE This implies that there cannot be any taps or junctions in this connection.
Consideration should be given to the characteristics of the load in selection of the type of
RCD.
– 10 – IEC 60364-7-721:2017 © IEC 2017
721.43 Protection against overcurrent
721.43.101 Final circuits
Each final circuit shall be protected by an overcurrent protective device which disconnects all
live conductors of that circuit.
721.5 Selection and erection of equipment
721.51 Common rules
721.510 Introduction
721.510.3 General
Where there is more than one electrically independent installation, each independent
installation shall be supplied by a separate connecting device and shall be segregated (in
accordance with general rules) such that supplies at different voltages cannot be
interconnected.
NOTE Independent installations. An installation is an assembly of associated electrical equipment having co-
ordinated characteristics to fulfil specific purposes.
721.512 Operational conditions and external influences
721.512.2 External influences
Consideration shall be given to the foreseeable external influences to which the caravan will
be subjected.
721.514 Identification
721.514.1 General
Instructions for use shall be provided with the caravan so that the caravan can be used safely.
The instructions shall comprise:
– a description of the installation;
– a description of the function of the RCD(s) and the use of the test button;
– a description of the function of the main isolating switch(es);
– the text of the instructions of Annex A.
– additional instructions necessary for user maintenance.
721.52 Wiring systems
721.521 Types of wiring systems
721.521.2 The wiring system shall use one or more of the following:
– insulated single-core cables, with flexible class 5 conductors, in non-metallic conduit or
non-metallic trunking system;
– insulated single-core cables, with stranded class 2 conductors (minimum of seven strands),
in non-metallic conduit or non-metallic trunking system;
– sheathed flexible cables.
All cables shall as a minimum meet the requirements of IEC 60332-1-2.
Non-metallic conduit systems shall comply with the relevant part of IEC 61386 (all parts).
Cable trunking systems and cable ducting systems shall comply with the relevant part of
IEC 61084 (all parts).
721.522 Selection and erection of wiring systems in relation to external influences
721.522.7 Vibration (AH)
721.522.7.1 As the wiring will be subjected to vibration, all wiring shall be protected against
mechanical damage either by location or by enhanced mechanical protection. Wiring passing
through metalwork shall be protected by means of suitable bushes or grommets, securely
fixed in position. Precautions shall be taken to avoid mechanical damage due to sharp edges
or abrasive parts.
721.522.8 Other mechanical stresses (AJ)
721.522.8.1.3 All cables, unless enclosed in rigid conduit, trunking, or flexible conduit shall
be supported at intervals not exceeding 0,4 m for vertical runs and 0,25 m for horizontal runs.
721.524 Cross-sectional areas of conductors
721.524.1 The cross-sectional area of every conductor shall be not less than 1,5 mm
copper or copper equivalent.
721.526 Electrical connections
721.526.1.101 Addition:
Connections between cables or conductors shall only be made in connecting boxes or by
electrical equipment.
NOTE Connections also include junctions and taps.
721.528 Proximity of wiring systems to other services
721.528.3 Proximity to non-electrical services
721.528.3.1
Add the following at the end of 528.3.1:
No electrical equipment including wiring systems, except:
a) ELV (extra low voltage) equi
...
IEC 60364-7-721 ®
Edition 2.0 2017-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –
Part 7-721: Requirements for special installations or locations – Electrical
installations in caravans and motor caravans
Installations électriques à basse tension –
Partie 7-721: Exigences pour les installations ou emplacements spéciaux –
Installations électriques dans les caravanes et caravanes à moteur
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International Standards for all electrical, electronic and related technologies.
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IEC 60364-7-721 ®
Edition 2.0 2017-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –
Part 7-721: Requirements for special installations or locations – Electrical
installations in caravans and motor caravans
Installations électriques à basse tension –
Partie 7-721: Exigences pour les installations ou emplacements spéciaux –
Installations électriques dans les caravanes et caravanes à moteur
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.020; 91.140.50 ISBN 978-2-8322-7406-4
– 2 – IEC 60364-7-721:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
721 Electrical installations in caravans and motor caravans . 7
721.1 Scope . 7
721.2 Normative references . 7
721.3 Terms and definitions . 8
721.31 Purposes, supplies and structure . 8
721.313 Supplies . 8
721.4 Protection for safety . 9
721.41 Protection against electric shock . 9
721.411 Protective measure: automatic disconnection of supply . 9
721.413 Protective measure: electrical separation . 9
721.414 Protective measure: extra-low voltage provided by SELV and PELV . 9
721.415 Additional protection . 9
721.43 Protection against overcurrent . 10
721.5 Selection and erection of equipment . 10
721.51 Common rules . 10
721.510 Introduction . 10
721.512 Operational conditions and external influences . 10
721.514 Identification . 10
721.52 Wiring systems . 10
721.521 Types of wiring systems . 10
721.522 Selection and erection of wiring systems in relation to external
influences . 11
721.524 Cross-sectional areas of conductors . 11
721.526 Electrical connections . 11
721.528 Proximity of wiring systems to other services . 11
721.53 Isolation, switching and control . 12
721.536 Isolation and switching . 12
721.54 Earthing arrangements and protective conductors . 12
721.543 Protective conductors . 12
721.55 Other equipment . 12
Annex A (normative) Instructions for electricity supply . 14
Annex B (informative) Extra low-voltage DC installations . 15
Annex C (informative) Current-carrying capacities . 21
Annex D (informative) List of notes concerning certain countries . 24
Bibliography . 25
Figure C.721.1 – Graph for obtaining minimum cross-sectional area for conductors for
fixed wiring installations with a voltage drop of 0,8 V . 21
Figure C.721.2 – Graph for obtaining minimum cross-sectional area for conductors for
battery cable installations with a voltage drop of 0,3 V . 22
Table 721.1 – Cross-sectional areas of flexible cords and cables for caravan
connection . 13
Table B.721.1 – Functional allocation and cross-sectional areas of cores for caravan
connectors . 18
– 4 – IEC 60364-7-721:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 7-721: Requirements for special installations or locations –
Electrical installations in caravans and motor caravans
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,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
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
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
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 60364-7-721 has been prepared by IEC technical committee 64:
Electrical installations and protection against electrical shock.
This bilingual version (2019-09) corresponds to the monolingual English version, published in
2017-06.
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) A minimum height of not less than 500 mm above the base of the cylinders is now required
for cables passing through the gas cylinder compartment. Where cables have to run
through a compartment such cables shall be protected against mechanical damage by
installation within a continuous conduit or duct passing through the compartment
(721.528.3.1).
b) It is now required that each independent installation shall be provided with its own main
isolating switch which shall disconnect all live conductors and which shall be suitably
placed in a readily accessible location in the caravan.(721.536.2.1.1)
c) The clause numbers for the protective measures not permitted (obstacles, placing out of
reach, non-conducting locations and earth-free local equipotential bonding) have been
changed.
The text of this International Standard is based on the following documents:
FDIS Report on voting
64/2200/FDIS 64/2210/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.
The French version of this standard has not been voted upon.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60364 series, published under the general title Low-voltage
electrical installations, can be found on the IEC website.
The reader's attention is drawn to the fact that Annex D lists all of the “in-some-country”
clauses on differing practices of a less permanent nature relating to the subject of this
standard.
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.
– 6 – IEC 60364-7-721:2017 © IEC 2017
INTRODUCTION
For the purpose of this part (IEC 60364-7-721) the requirements of the general Parts 1 to 6 of
IEC 60364 apply.
The IEC 60364-7-7XX parts of IEC 60364 contain particular requirements for special
installations or locations which are based on the requirements of the general parts of
IEC 60364 (IEC 60364-1 to IEC 60364-6). These IEC 60364-7-7XX parts are considered in
conjunction with the requirements of the general parts.
The particular requirements of this part of IEC 60364 supplement, modify or replace certain of
the requirements of the general parts of IEC 60364 being valid at the time of publication of
this part. The absence of reference to the exclusion of a part or a clause of a general part
means that the corresponding clauses of the general part are applicable (undated reference).
Requirements of other 7XX parts being relevant for installations covered by this part also
apply. This part may therefore also supplement, modify or replace certain of these
requirements valid at the time of publication of this part.
The clause numbering of this part follows the pattern and corresponding references of
IEC 60364. The numbers following the particular number of this part are those of the
corresponding parts, or clauses of the other parts of the IEC 60364 series, valid at the time of
publication of this part, as indicated in the normative references of this document (dated
reference).
If requirements or explanations additional to those of the other parts of the IEC 60364 series
are needed, the numbering of such items appears as 721.101, 721.102, 721.103 etc.
In the case where new or amended general parts with modified numbering were published
after this part was issued, the clause numbers referring to a general part in this 721 part may
no longer align with the latest edition of the general part. Dated references should be
observed.
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –
Part 7-721: Requirements for special installations or locations –
Electrical installations in caravans and motor caravans
721 Electrical installations in caravans and motor caravans
721.1 Scope
The particular requirements of this part of IEC 60364 apply to electrical installations in
caravans and motor caravans.
They apply to those electrical circuits and equipment intended for the use of the caravan for
habitation purposes.
They do not apply to those electrical circuits and equipment for automotive purposes.
They do not apply to the electrical installations of mobile homes, residential park homes and
transportable units.
NOTE 1 For mobile homes and residential park homes the general requirements apply.
NOTE 2 For transportable units see IEC 60364-7-717.
NOTE 3 For the purposes of this document, caravans and motor caravans are referred to as “caravans”
The particular requirements of some parts from the IEC 60364-7 series can also apply to such
installations in caravans, for example IEC 60364-7-701.
721.2 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 60038, IEC standard voltages
IEC 60309-2, Plugs, socket-outlets and couplers for industrial purposes – Part 2: Dimensional
interchangeability requirements for pin and contact-tube accessories
IEC 60332-1-2, 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 60947-2, Low-voltage switchgear and controlgear – Part 2: Circuit-breakers
IEC 61008-1, Residual current operated circuit-breakers without integral overcurrent
protection for household and similar uses (RCCBs) – Part 1: General rules
IEC 61009-1, Residual current operated circuit-breakers with integral overcurrent protection
for household and similar uses (RCBOs) – Part 1: General rules
IEC 61084 (all parts), Cables trunking and ducting systems for electrical installations
– 8 – IEC 60364-7-721:2017 © IEC 2017
IEC 61386 (all parts), Conduit systems for cable management
IEC 62423, Type F and Type B residual current operated circuit-breakers with and without
integral overcurrent protection for household and similar uses
721.3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
721.3.1
leisure accommodation vehicle
unit of living accommodation for temporary or seasonal occupation that may meet the
requirements for the construction and use of road vehicles
721.3.1.1
caravan
trailer leisure accommodation vehicle, used for touring, that meets the requirements for the
construction and use of road vehicles
721.3.1.2
motor caravan
self-propelled leisure accommodation vehicle, used for touring, that meets the requirements
for the construction and use of road vehicles
Note 1 to entry: A motor caravan is either adapted from a series production vehicle, or designed and built on an
existing chassis, with or without the driving cab, the accommodation being either fixed or dismountable.
721.3.1.3
mobile home
transportable leisure accommodation vehicle that includes means for mobility but does not
meet the requirements for the construction and use of road vehicles
721.3.1.4
residential park home
factory produced relocatable dwelling
721.31 Purposes, supplies and structure
721.313 Supplies
721.313.1 General
721.313.1.101 The nominal supply system voltage shall be selected from IEC 60038.
The nominal AC supply voltage of the installation of the caravan shall not exceed 230 V
single-phase, or 400 V three-phase.
The nominal DC supply voltage of the installation of the caravan shall not exceed 48 V.
721.4 Protection for safety
721.41 Protection against electric shock
721.410.3.5
Add the following:
The protective measures of obstacles and placing out of reach as specified in Annex B of
IEC 60364-4-41:2005 shall not be used.
721.410.3.6
Add the following:
The protective measures of non-conducting locations and earth-free local equipotential
bonding as specified in Annex C of IEC 60364-4-41:2005 shall not be used.
NOTE This precludes the use of class 0 equipment.
721.411 Protective measure: automatic disconnection of supply
721.411.3.1.2 Protective equipotential bonding
Metal frame parts or thereto connected construction parts shall be connected through main
protective bonding conductors to the main earthing terminal within the caravan.
721.413 Protective measure: electrical separation
The protective measure: electrical separation shall not be used, except for a shaver socket-
outlet.
721.414 Protective measure: extra-low voltage provided by SELV and PELV
Any part of a caravan installation operating at extra-low voltage shall comply with the
requirements of Clause 414.
For extra-low voltage DC power sources, a maximum of 48 V are allowed. In exceptional
cases, when AC extra-low voltage is required, the voltage (rms) is not allowed to exceed
48 V.
The requirements of Part 721 are also applicable to extra low-voltage DC installation. See
Annex B for recommendations that can be applied in addition.
721.415 Additional protection
721.415.101 Additional protection: residual current protective devices (RCDs)
Addition:
Where protection by automatic disconnection of supply is used, a residual current device with
a rated residual operating current not exceeding 30 mA, complying with IEC 60947-2,
IEC 61008-1, IEC 61009-1 or IEC 62423 breaking all live conductors, shall be provided. Each
supply inlet shall be directly connected to its associated RCD.
NOTE This implies that there cannot be any taps or junctions in this connection.
Consideration should be given to the characteristics of the load in selection of the type of
RCD.
– 10 – IEC 60364-7-721:2017 © IEC 2017
721.43 Protection against overcurrent
721.43.101 Final circuits
Each final circuit shall be protected by an overcurrent protective device which disconnects all
live conductors of that circuit.
721.5 Selection and erection of equipment
721.51 Common rules
721.510 Introduction
721.510.3 General
Where there is more than one electrically independent installation, each independent
installation shall be supplied by a separate connecting device and shall be segregated (in
accordance with general rules) such that supplies at different voltages cannot be
interconnected.
NOTE Independent installations. An installation is an assembly of associated electrical equipment having co-
ordinated characteristics to fulfil specific purposes.
721.512 Operational conditions and external influences
721.512.2 External influences
Consideration shall be given to the foreseeable external influences to which the caravan will
be subjected.
721.514 Identification
721.514.1 General
Instructions for use shall be provided with the caravan so that the caravan can be used safely.
The instructions shall comprise:
– a description of the installation;
– a description of the function of the RCD(s) and the use of the test button;
– a description of the function of the main isolating switch(es);
– the text of the instructions of Annex A.
– additional instructions necessary for user maintenance.
721.52 Wiring systems
721.521 Types of wiring systems
721.521.2 The wiring system shall use one or more of the following:
– insulated single-core cables, with flexible class 5 conductors, in non-metallic conduit or
non-metallic trunking system;
– insulated single-core cables, with stranded class 2 conductors (minimum of seven strands),
in non-metallic conduit or non-metallic trunking system;
– sheathed flexible cables.
All cables shall as a minimum meet the requirements of IEC 60332-1-2.
Non-metallic conduit systems shall comply with the relevant part of IEC 61386 (all parts).
Cable trunking systems and cable ducting systems shall comply with the relevant part of
IEC 61084 (all parts).
721.522 Selection and erection of wiring systems in relation to external influences
721.522.7 Vibration (AH)
721.522.7.1 As the wiring will be subjected to vibration, all wiring shall be protected against
mechanical damage either by location or by enhanced mechanical protection. Wiring passing
through metalwork shall be protected by means of suitable bushes or grommets, securely
fixed in position. Precautions shall be taken to avoid mechanical damage due to sharp edges
or abrasive parts.
721.522.8 Other mechanical stresses (AJ)
721.522.8.1.3 All cables, unless enclosed in rigid conduit, trunking, or flexible conduit shall
be supported at intervals not exceeding 0,4 m for vertical runs and 0,25 m for horizontal runs.
721.524 Cross-sectional areas of conductors
721.524.1 The cross-sectional area of every conductor shall be not less than 1,5 mm
copper or copper equivalent.
721.526 Electrical connections
721.526.1.101 Addition:
Connections between cables or conductors shall only be made in connecting boxes or by
electrical equipment.
NOTE Connections also include junctions and taps.
721.528 Proximity of wiring systems to other services
721.528.3 Proximity to non-electrical services
721.528.3.1
Add the following at the end of 528.3.1:
No electrical equipment including wiring systems, except:
a) ELV (extra low voltage) equipment for gas supply control;
b) cables running through a gas compartment without connection shall be installed in any
gas cylinder compartment.
Such electrical installations and components shall be constructed and installed so that they
are not a potential source of ignition.
Where cables have to run through such a compartment such cables shall be protected against
mechanical damage by installation within a continuous conduit or duct passing through the
compartment at a height of not less than 500 mm above the base of the cylinders.
Where installed in a position where it is likely to be subject to mechanical damage this conduit
or duct shall be able to withstand an impact equivalent to AG3.721.53 isolation, switching
and control.
– 12 – IEC 60364-7-721:2017 © IEC 2017
721.53 Isolation, switching and control
721.536 Isolation and switching
721.536.2 Isolation
721.536.2.1.1 Each independent installation shall be provided with its own main isolating
switch which shall disconnect all live conductors and which shall be suitably placed in a
readily accessible location in the caravan. In an installation consisting of only one final circuit,
the isolating switch may be the overcurrent protection device providing such a device meets
the requirements for isolation.
721.536.2.1.1.101 A notice in durable material shall be permanently fixed in the vicinity of
the main isolating switch inside the caravan, bearing the text shown in Annex A in the official
language(s) of the country in which the caravan is to be sold for the first time, in indelible and
easily legible characters.
721.54 Earthing arrangements and protective conductors
721.543 Protective conductors
721.543.2 Types of protective conductors
721.543.2.1 Circuit protective conductors shall be incorporated in a multicore cable or in a
conduit or trunking together with the live conductors.
721.544.1 Protective bonding conductors for connection to the main earthing terminal
721.544.1.101 The terminations of protective bonding conductors connecting the conductive
structure of the unit shall be accessible and protected against corrosion.
721.55 Other equipment
721.55.2 General requirements
721.55.2.101 Inlets
721.55.2.101.1 Any AC electrical inlet on the caravan shall be an appliance inlet complying
with IEC 60309-2.
721.55.2.101.2 The inlet, if any, shall be installed
a) not more than 1,8 m above ground level,
b) in a readily accessible position,
c) have a minimum protection of IP44 with or without a connector engaged, and
d) the inlet shall not protrude significantly beyond the body of the caravan.
721.55.2.102 Accessories
721.55.2.102.1 Every low-voltage socket-outlet, other than a shaver socket-outlet, shall
incorporate an earth contact.
721.55.2.102.2 Every socket-outlet supplied at extra-low voltage shall have its voltage
visibly marked.
721.55.2.102.3 Where an accessory is located in a position in which it is exposed to the
effects of moisture it shall be constructed or enclosed so as to provide a degree of protection
not less than IPX4.
721.55.2.102.4 Each luminaire in a caravan shall preferably be fixed directly to the structure
or lining of the caravan. Where a pendant luminaire is installed in a caravan, provision shall
be made for securing the luminaire to prevent damage when the caravan is moved.
Accessories for the suspension of pendant luminaires shall be suitable for the mass
suspended and the forces associated with vehicle movement.
721.55.2.102.5 A luminaire intended for dual voltage operation shall comply with the
appropriate standard.
721.55.2.102.6
Table 721.1 – Cross-sectional areas of flexible cords
and cables for caravan connection
Rated current Minimum cross-sectional area
A mm
16 2,5
25 4
32 6
63 16
100 35
The appliance inlet installed under 721.55.2.101 shall comply with IEC 60309-2, and the
means of connection to the caravan pitch socket-outlet shall comprise the following:
a) a plug complying with IEC 60309-2; and
b) a flexible cord or cable
– of 25 m (±2 m) continuous length,
– of harmonized code designation IEC 60245 (code 57) or equivalent,
– incorporating a protective conductor, with a colour identification according to the
appropriate IEC standard, and
– with a cross-sectional area in accordance with Table 721.1, and
c) a connector complying with IEC 60309-2.
The means of connection to the caravan pitch socket-outlet need not be supplied with the
caravan.
– 14 – IEC 60364-7-721:2017 © IEC 2017
Annex A
(normative)
Instructions for electricity supply
A.721.1 Connection
a) Before connecting the caravan installation to the electricity supply, check that
1) the supply available at the caravan pitch supply point is suitable for the caravan
electrical installation and appliances, the voltage, frequency and current rating are
suitable,
2) the cable and means of connection are suitable, and
3) the main isolating switch in the caravan is in the OFF position.
WARNING The caravan supply flexible cable should be fully uncoiled to avoid damage by
overheating.
b) Check the cable, the plug and the connector for damage.
c) Open the cover of the appliance inlet provided at the caravan, if any, and insert the
connector of the flexible cable.
d) Insert the plug of the flexible cable into the electricity outlet provided on the pitch supply
point.
e) Switch on the caravan main isolating switch.
f) Check the operation of residual current devices fitted in the caravan by depressing the
test buttons and reset.
In case of doubt or, if after carrying out the above procedure the supply does not become
available, or if the supply fails, consult the caravan park operator.
A.721.2 Disconnection
Switch off at the caravan main isolating switch, unplug the cable, first on the caravan pitch
supply point side and then at the caravan appliance inlet, if any.
A.721.3 Periodic inspection
Preferably not less than once every three years and annually if the caravan is used
frequently, the caravan electrical installation and supply cable should be inspected and tested
by a competent electrician and a report on their condition obtained.
Annex B
(informative)
Extra low-voltage DC installations
B.721.31 Purposes, supplies and structure
B.721.313 Supplies
B.721.313.101 Sources of supply
The supply should be obtained from one or more of the following sources:
a) the electrical installation of the towing vehicle;
b) an auxiliary battery mounted in the caravan;
c) a low-voltage DC supply via a transformer/rectifier unit complying with IEC 60335-1 and
IEC 61558-2-6;
d) a DC generator that is driven by any form of energy;
e) solar photovoltaic (PV) power supply systems or similar.
B.721.51 Common rules
B.721.514 Identification
B.721.514.1 General
The following information should be provided in the instructions for use and should be in the
official language(s) of the country in which the caravan is to be sold:
a) A warning worded as follows: “Any replacement of an auxiliary battery should be of the
same type and specification as that originally specified by the caravan manufacturer”.
b) Instructions on the maintenance and recharging of an auxiliary battery where it is fitted.
Where a battery charger is provided, instructions on its safe use should be included.
c) Instructions on selecting and installing an auxiliary battery in a compartment, if the
caravan is intended for the installation of an auxiliary battery.
d) Details of the warning notice specified in B.721.55.3.5 and its importance for safety.
e) In order to ensure safe operation of the electrical installation, a simplified diagram of the
wiring of the ELV and LV installation, with details of the cable colours and/or marking and
the nominal values of the overcurrent protective devices should be provided.
f) Type of appliances that can be used and from what source of supply.
g) Instructions for the correct operation and maintenance of fitted appliances, as supplied by
the appliance manufacturer.
h) A warning worded as follows: “Always disconnect the electrical connector between the
towing vehicle and the caravan before connecting an LV supply to the caravan and before
charging the caravan battery by any other means”.
B.721.515 Prevention of mutual detrimental influence
B.721.515.2 The ELV installation should be so installed that the protective measures of the
LV installation against direct contact, or in case of indirect contact are not impaired.
It should be ensured that operating currents of the ELV installation do not flow in the
protective conductors of the LV installation.
– 16 – IEC 60364-7-721:2017 © IEC 2017
B.721.521 Types of wiring systems
B.721.521.2 Cables should be of stranded construction and should comply with IEC 60227
(all parts), IEC 60245 (all parts) or ISO 6722 (all parts).
B.721.523 Current-carrying capacities
B.721.523.1 The cross-sectional areas of the conductors selected for the fixed wiring should
be in accordance with Annex C. Annex C does not apply to sensor and data lines.
B.721.525 Voltage drop in consumers' installations
Under normal service conditions, the voltage at the terminals of any fixed current-using
equipment should be greater than the lower limit corresponding to the IEC standard relevant
to the equipment. Where the equipment is not the subject of an IEC standard, the voltage at
the terminals should be such as not to impair the safe functioning of that equipment. In the
absence of precise data, a voltage drop of 0,8 V from the power supply to the equipment may
be allowed.
The charging current I [A] to determine the voltage drop is established by Formula (B.1).
c
c⋅0,1
I = (B.1)
c
t
where
I is the charging current, in A;
c
c is the battery capacity, in Ah;
t is the period, in h.
B.721.528 Proximity of wiring systems to other services
B.721.528.3 Proximity to non-electrical services
B.721.528.3.5.101 Cable runs and LPG installations
Cables including those used for automotive purposes should not be run through a
compartment or housing intended for liquefied petroleum gas storage cylinders. Where cables
have to run through such a compartment or housing, they should be run at a height of not less
than 500 mm above the base of the cylinders, and such cables should be protected against
mechanical damage by installation within a continuous gas tight conduit or duct passing
through the compartment.
Where installed, this conduit or duct should be able to withstand an impact equivalent to AG3
without visible physical damage.
ELV cables and electrical equipment are only to be installed within the LPG cylinder
compartment or housing if the installation serves the operation of the gas cylinders (e.g.
indication of empty gas cylinders) or is for use within the compartment or housing. Such
electrical installations and components should be constructed and installed so that they are
not a source of ignition and are in accordance with the relevant standards for any hazardous
area classification of the compartment or housing.
B.721.53 Isolation, switching and control
B.721.533 Devices for protection against overcurrent
B.721.533.1 General requirements
B.721.533.1.101 The overcurrent protective device for the power supply from the towing
vehicle should be installed as near as possible to the auxiliary battery, but in no case more
than 1 000 mm away. The overcurrent protective device for the auxiliary battery should be
fitted at the end of the battery cable and before the fixed installation. The ELV output of the
transformer/rectifier unit and of the DC generator should be provided with an overcurrent
protective device unless this is already incorporated within the unit or generator. The
protective device should be installed as near as possible to the unit or generator and, in all
cases, upstream of the distribution circuits.
B.721.533.1.102 Overcurrent protective devices should be either fuse links according to
ISO 8820 (all parts) or suitable miniature circuit-breakers.
B.721.533.1.103 Fuses should be physically protected against accidental mechanical
damage.
B.721.533.1.104 Overcurrent protective devices should not be fitted in a fuel storage
compartment or fuel storage housing intended for the storage of liquefied petroleum gas
cylinders or in the compartment for housing an auxiliary battery.
B.721.55 Other equipment
B.721.55.2 General requirements
B.721.55.2.101 Inlets
The inlet, when the plug is disconnected, should be protected against the ingress of water,
foreign bodies and accidental damage.
B.721.55.2.102 Accessories
The means of connection to the towing vehicle should be supplied with the caravan and
comprise the following:
a) a plug complying with ISO 1724 and ISO 3732 or ISO 11446 (all parts), and
b) a flexible cord or cable with the number of cores with the minimum cross-sectional area
and the allocation according to Table B.721.1 and a length not exceeding 5 m, and
c) a connector complying with ISO 1724 and ISO 3732 or ISO 11446 (all parts).
– 18 – IEC 60364-7-721:2017 © IEC 2017
Table B.721.1 – Functional allocation and cross-sectional areas
of cores for caravan connectors
Contact numbers Minimum cross-
Core
Function sectional area
No.
ISO 11446 ISO 1724 2
mm
1 Left-hand direction – indicator light 1 1 1,5
2 Rear fog light 2 2 1,5
a a
3 Common return for core nos. 1, 2, 4, 5, 6, 7 3 3 2,5
and 8
4 Right-hand direction – indicator light 4 4 1,5
5 Right hand-rear position and marker lights, and 5 5 1,5
rear-registration-plate illumination device
6 Stop lights 6 6 1,5
7 Left-hand rear position and marker lights, and 7 7 1,5
rear-registration-plate illumination device
ISO 3732
8 Reversing light 8 1 1,5
9 Continuous power supply 9 4 2,5
10 Power supply controlled by ignition switch 10 6 2,5
a a
11 Return for core No. 10 11 7 2,5
12 Coding for coupled trailer 12 2 –
a a
13 Return for core No. 9 13 3 2,5
14 No allocation – 5 1,5
a
These return circuits should not be electrically connected in the trailer.
B.721.55.2.103 Auxiliary batteries
B.721.55.2.103.1 Type of battery
An auxiliary battery should be of the rechargeable type.
NOTE Non-rechargeable batteries are not auxiliary batteries. They can be used i
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