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.

General Information

Status
Published
Publication Date
14-Jun-2017
Current Stage
PPUB - Publication issued
Start Date
15-Jun-2017
Completion Date
15-Jun-2017
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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
IEC 60364-7-721:2017-06 (en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
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

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

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

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

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IEC 60364-7-721:2017 © IEC 2017 – 3 –
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

---------------------- Page: 5 ----------------------
– 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

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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 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

---------------------- Page: 6 ----------------------
IEC 60364-7-721:2017 © IEC 2017 – 5 –
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.
---------------------- Page: 7 ----------------------
– 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.
---------------------- Page: 8 ----------------------
IEC 60364-7-721:2017 © IEC 2017 – 7 –
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

---------------------- Page: 9 ----------------------
– 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.

---------------------- Page: 10 ----------------------
IEC 60364-7-721:2017 © IEC 2017 – 9 –
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.
---------------------- Page: 11 ----------------------
– 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).

---------------------- Page: 12 ----------------------
IEC 60364-7-721:2017 © IEC 2017 – 11 –

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
...

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