SIST IEC 60364-1:2006

Low-voltage electrical installations - Part 1: Fundamental principles, assessment of general characteristics, definitions

Gives the rules for the design, erection, and verification of electrical installations. The rules are intended to provide for the safety of persons, livestock and property against dangers and damage which may arise in the reasonable use of electrical installations and to provide for the proper functioning of those installations.[
]IEC 60364-1 applies to the design, erection and verification of electrical installations such as those of a) residential premises; b) commercial premises; c) public premises; d) industrial premises; e) agricultural and horticultural premises; f) prefabricated buildings; g) caravans, caravan sites and similar sites; h) construction sites, exhibitions, fairs and other installations for temporary purposes; i) marinas; j) external lighting and similar installations; k) medical locations; l) mobile or transportable units; m) photovoltaic systems; n) low-voltage generating sets.[
]IEC 60364-1 covers[
]a) circuits supplied at nominal voltages up to and including 1 000 V a.c. or 1 500 V d.c.;[
]b) circuits, other than the internal wiring of apparatus, operating at voltages exceeding 1 000 V and derived from an installation having a voltage not exceeding 1 000 V a.c., for example, discharge lighting, electrostatic precipitators;[
]c) wiring systems and cables not specifically covered by the standards for appliances;[
]d) all consumer installations external to buildings;[
]e) fixed wiring for information and communication technology, signalling, control and the like (excluding internal wiring of apparatus);[
]f) the extension or alteration of the installation and also parts of the existing installation affected by the extension or alteration.

Installations électriques à basse tension - Partie 1: Principes fondamentaux, détermination des caractéristiques générales, définitions

Donne des règles pour la conception, la mise en  uvre et la vérification des installations électriques. Ces règles sont Destinées à assurer la sécurité des personnes, des animaux et des biens contre les dangers et les dommages susceptibles de se produire lors d'une utilisation raisonnable des installations électriques et à assurer le fonctionnement correct de ces installations.[
]La CEI 60364-1 s'applique à la conception, à la mise en  uvre et aux vérifications des installations électriques telles que celles des: a) bâtiments à usage d'habitation; b) bâtiments à usage commercial; c) établissements recevant du public; d) établissements industriels; e) établissements agricoles et horticoles; f) bâtiments préfabriqués; g) caravanes, terrains de campement et installations analogues; h) hantiers, fêtes foraines, foires, expositions et autres installations temporaires; i) marinas; j) éclairages extérieurs et analogues; k) locaux médicaux; l) unités  mobiles ou transportables; m) réseaux photovoltaïques; n) groupes générateurs à basse tension.[
]La CEI 60364-1 est applicable:[
]a) aux circuits alimentés sous une tension nominale au plus égale à 1 000 V en courant alternatif et à 1 500 V en courant continu;[
]b) aux circuits, autres que les circuits internes des appareils, fonctionnant sous une tension supérieure à 1 000 V à partir d'une installation de tension au plus égale à 1 000 V en courant alternatif, par exemple: circuits de lampes à décharge, dépoussiéreurs électrostatiques;[
]c) à tout câblage et à toute canalisation qui ne font pas l'objet des normes relatives aux appareils d'utilisation;[
]d) à toutes les installations d'utilisateur situées à l'extérieur des bâtiments;[
]e) aux canalisations fixes de communication, de signalisation ou de commande (à l'exception de circuits internes des appareils);[
]f) aux extensions ou modifications d'installations ainsi qu'aux parties des installations existantes affectées par ces extensions ou modifications.

Nizkonapetostne električne inštalacije – 1. del: Temeljna načela, ocenjevanje splošnih značilnosti, definicije

General Information

• Status: Withdrawn
• Publication Date: 31-Aug-2006
• Withdrawal Date: 24-Oct-2010
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: ELI - Electrical and communication installations
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 29-Mar-2010
• Due Date: 21-Apr-2010
• Completion Date: 25-Oct-2010
• Directive: TRRTP131 - Tehnična smernica TSG-N-002:2009 - Nizkonapetostne električne inštalacije
• Ref Project: IEC 60364-1 - Low-voltage electrical installations - Part 1: Fundamental principles, assessment of general characteristics, definitions

Relations

• Replaced By: SIST HD 60364-1:2008 - Low-voltage electrical installations -- Part 1: Fundamental principles, assessment of general characteristics, definitions
• Effective Date: 01-May-2010

Overview

IEC 60364-1 - "Low‑voltage electrical installations - Part 1: Fundamental principles, assessment of general characteristics, definitions" - sets out the foundational rules for the design, erection and verification of low‑voltage electrical installations. Applicable to circuits supplied at nominal voltages up to 1 000 V a.c. and 1 500 V d.c., the standard is intended to ensure the safety of persons, livestock and property and to support the proper functioning and maintainability of installations. The 5th edition (2005) and its corrigendum (2009) define scope, principles and terminology used across the IEC 60364 series.

Key Topics

• Fundamental principles of protection: protection against electric shock, thermal effects, overcurrent, fault currents, voltage disturbances and electromagnetic influences, and protection against supply interruption.
• Design considerations: characteristics of supply(s), nature of demand, environmental conditions, conductor sizing, wiring methods, protective equipment, emergency control and accessibility.
• Conductor arrangement and system earthing: classification and diagrams of TN, TT, IT and mixed systems for a.c. and d.c. installations.
• Selection and documentation: criteria for selecting electrical equipment and required documentation for installation design and verification.
• Erection and verification: rules for proper installation, initial verification (testing) and periodic verification (inspections and maintenance).
• Assessment of general characteristics: maximum demand, diversity, division of installation, compatibility and maintainability.
• Special topics included: continuity of service, safety services and provisions for temporary installations, marinas, medical locations, photovoltaic (PV) systems and low‑voltage generating sets.

Applications

IEC 60364-1 is used by professionals responsible for low‑voltage installations in:

• Residential, commercial and public buildings
• Industrial and agricultural premises
• Prefabricated and mobile/transportable units (caravans, construction sites, exhibitions)
• Marinas, external lighting, medical locations and photovoltaic systems
• Facility managers, electrical designers, contractors, inspectors and regulatory authorities rely on this standard to:
  • Define safe system earthing and protective measures
  • Specify conductor sizing, protection devices and documentation requirements
  • Establish verification and periodic inspection regimes for compliance and safety

Related Standards

• Other parts of the IEC 60364 series: Part 4 (Protection for safety), Part 5 (Selection and erection), Part 6 (Verification), Part 7 (Special installations or locations).
• Cross‑reference: IEC 60050‑826 (terminology for electrical installations) is aligned via Annex B.

IEC 60364-1 is foundational for anyone implementing or auditing low‑voltage electrical installations, providing the vocabulary, safety principles and assessment framework used throughout the IEC 60364 family.

Standards Content (Sample)

SLOVENSKI STANDARD
SIST IEC 60364-1:200
01-IHEUXDU-200
1L]NRQDSHWRVWQHHOHNWULþQHLQãWDODFLMH±GHO7HPHOMQDQDþHODRFHQMHYDQMH
VSORãQLK]QDþLOQRVWLGHILQLFLMH
Low-voltage electrical installations - Part 1: Fundamental principles, assessment of
general characteristics, definitions
Installations électriques à basse tension - Partie 1: Principes fondamentaux,
détermination des caractéristiques générales, définitions
Ta slovenski standard je istoveten z: IEC 60364-1
ICS:
91.140.50 Sistemi za oskrbo z elektriko Electricity supply systems
SIST IEC 60364-1: en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
...

SLOVENSKI SIST IEC 60364-1:2006

STANDARD
september 2006
Nizkonapetostne električne inštalacije – 1. del: Temeljna načela, ocenjevanje
splošnih značilnosti, definicije
Low-voltage electrical installations - Part 1: Fundamental principles, assessment of
general characteristics, definitions
ICS 91.140.50 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

Edition 5.0 2005-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage electrical installations –
Part 1: Fundamental principles, assessment of general characteristics,
definitions
Installations électriques à basse tension –
Partie 1: Principes fondamentaux, détermination des caractéristiques générales,
définitions
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 91.140.50 ISBN 2-8318-8354-7

60364-1  IEC:2005 – 3 –
CONTENTS
FOREWORD.5

11 Scope.7
12 Normative references .9
13 Fundamental principles .10
131 Protection for safety.10
131.1 General.10
131.2 Protection against electric shock .10
131.3 Protection against thermal effects .11
131.4 Protection against overcurrent.11
131.5 Protection against fault currents .11
131.6 Protection against voltage disturbances and measures against
electromagnetic influences .11
131.7 Protection against power supply interruption .12
132 Design .12
132.1 General.12
132.2 Characteristics of available supply or supplies .12
132.3 Nature of demand.13
132.4 Electric supply systems for safety services or standby electric
supply systems.13
132.5 Environmental conditions .13
132.6 Cross-sectional area of conductors .13
132.7 Type of wiring and methods of installation.14
132.8 Protective equipment.14
132.9 Emergency control .14
132.10 Disconnecting devices.14
132.11 Prevention of mutual detrimental influence .14
132.12 Accessibility of electrical equipment .14
132.13 Documentation for the electrical installation .15
133 Selection of electrical equipment .29
133.1 General.29
133.2 Characteristics.29
133.3 Conditions of installation .15
133.4 Prevention of harmful effects.16
134 Erection and verification of electrical installations .16
134.1 Erection .16
134.2 Initial verification.17
134.3 Periodic verification.17
20 Terms and definitions .17
30 Assessment of general characteristics.17
31 Purposes, supplies and structure.17
311 Maximum demand and diversity .17
312 Conductor arrangement and system earthing .17
312.1 Current-carrying conductors depending on kind of current.18
312.2 Types of system earthing .19

60364-1  IEC:2005 – 5 –
313 Supplies.36
313.1 General.36
313.2 Supplies for safety services and standby systems .36
314  Division of installation.36
32 Classification of external influences.37
33 Compatibility .37
33.1 Compatibility of characteristics .37
33.2 Electromagnetic compatibility .37
34 Maintainability .37
35 Safety services.38
35.1  General .38
35.2  Classification .38
36 Continuity of service.38

Annex A (informative) Numbering system and plan of IEC 60364 series.39
Annex B (informative) Definitions – Application guide and explanations to selected
terms of IEC 60050-826 (IEV 826 – Electrical Installations) .42
Annex C (informative) Comparison of the structure of IEC 60364-1 fourth edition 2001
and IEC 60364-1 fifth edition 2005.45

Bibliography.47

Figure 1 – Single-phase 2-wire .18
Figure 2 – Single-phase 3-wire .18
Figure 3 – Two-phase 3-wire.18
Figure 4 – Three-phase 3-wire .18
Figure 5 – Three-phase 4-wire .19
Figure 6 – 2-wire.19
Figure 7 – 3-wire.19
Figure 31A1 – TN-S system with separate neutral conductor and protective conductor
throughout the system .20
Figure 31A2 – TN-S system with separate earthed line conductor and protective
conductor throughout the system .21
Figure 31A3 – TN-S system with earthed protective conductor and no distributed
neutral conductor throughout the system .21
Figure 31B1 – TN-C-S system 3-phase, 4-wire, where the PEN is separated into PE
and N elsewhere in the installation .22
Figure 31B2 – TN-C-S system 3-phase, 4-wire where the PEN is separated into PE
and N at the origin of the installation.23
Figure 31B3 – TN-C-S system – Single-phase, 2-wire where the PEN is separated into
PE and N at the origin of the installation .23
Figure 31C – TN-C system with neutral and protective conductor functions combined in
a single conductor throughout the system .24
Figure 31D – TN-C-S multiple source system with separate protective conductor and
neutral conductor to current using equipment.25
Figure 31E – TN multiple source system with protective conductor and no neutral
conductor throughout the system for 2- or 3-phase load.26

60364-1  IEC:2005 – 7 –
Figure 31F1 – TT system with separate neutral conductor and protective conductor
throughout the installation.27
Figure 31F2 – TT system with earthed protective conductor and no distributed neutral
conductor throughout the installation .28
Figure 31G1 – IT system with all exposed-conductive-parts interconnected by a
protective conductor which is collectively earthed .29
Figure 31G2 – IT system with exposed-conductive-parts earthed in groups or
individually.30
Figure 31H – TN-S d.c. system .31
Figure 31J – TN-C d.c. system.32
Figure 31K – TN-C-S d.c. system.33
Figure 31L – TT d.c. system .34
Figure 31M – IT d.c. system.35
Figure B.1 – Zone of arm’s reach.43

Table A.1 – Numbering system of IEC 60364 series.39
Table A.2 – Plan of IEC 60364 series: Electrical installations of buildings .40

60364-1  IEC:2005 – 9 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –

Part 1: Fundamental principles, assessment of
general characteristics, definitions

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
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 60364-1 has been prepared by IEC Technical Committee 64:
Electrical installations and protection against electric shock.
This fifth edition cancels and replaces the fourth edition, published in 2001. It constitutes a
technical revision.
The main changes with respect to the previous edition are:
– in order to complete the scope, the new items external lighting and similar installations,
medical locations, mobile or transportable units, photovoltaic power supply units and low-
voltage generating sets are added;
– in Clause 131, "Fundamental principles", the list of hazards which may arise in electrical
installations is completed; furthermore, a new subclause dealing with protection against
voltage disturbances and measures against electromagnetic influences and a new
subclause dealing with protection against power supply interruption are added;

60364-1  IEC:2005 – 11 –
– in Clause 132, "Design", the new subclause "Documentation for the electrical installation"
is added;
– in Clause 134, "Erection and verification of electrical installations", the new subclause "
periodic verification" is added;
– the former Clause 312, "Types of distribution system" is renamed "Conductor arrangement
and system earthing" and, in the relevant subclauses, several new figures are included for
better understanding of the different kind of a.c. and d.c. circuits and types of systems and
their earthing being applied nowadays in IEC member countries;
– in 33.1, "Compatibility of characteristics", a new item for excessive PE conductor currents
is added;
– a new Clause 36, "Continuity of service", is included;
– Annex B is aligned with the second edition of IEC 60050-826:2004.
The text of this standard is based on the following documents:
FDIS Report on voting
64/1488/FDIS 64/1499/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60364 consists of the following parts, under the general title Low-voltage electrical
installations:
Part 1: Fundamental principles, assessment of general characteristics, definitions
Part 4: Protection for safety
Part 5: Selection and erection of electrical equipment
Part 6: Verification
Part 7: Requirements for special installations or locations
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
60364-1  IEC:2005 – 13 –
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –

Part 1: Fundamental principles, assessment of
general characteristics, definitions

11 Scope
The rules are intended to provide for the safety of persons, livestock and property against
dangers and damage which may arise in the reasonable use of electrical installations and to
provide for the proper functioning of those installations.
11.1 IEC 60364-1 applies to the design, erection and verification of electrical installations
such as those of
a) residential premises;
b) commercial premises;
c) public premises;
d) industrial premises;
e) agricultural and horticultural premises;
f) prefabricated buildings;
g) caravans, caravan sites and similar sites;
h) construction sites, exhibitions, fairs and other installations for temporary purposes;
i) marinas;
j) external lighting and similar installations (see, however ,11.3e));
k) medical locations;
l) mobile or transportable units;
m) photovoltaic systems;
n) low-voltage generating sets.
NOTE “Premises” covers the land and all facilities including buildings belonging to it.
11.2 IEC 60364-1 covers
a) circuits supplied at nominal voltages up to and including 1 000 V a.c. or 1 500 V d.c.;
For a.c., the preferred frequencies which are taken into account in this standard are
50 Hz, 60 Hz and 400 Hz. The use of other frequencies for special purposes is not
excluded.
b) circuits, other than the internal wiring of apparatus, operating at voltages exceeding 1 000 V
and derived from an installation having a voltage not exceeding 1 000 V a.c., for example,
discharge lighting, electrostatic precipitators;
—————————
The numbering system is explained in Annex A.

60364-1  IEC:2005 – 15 –
c) wiring systems and cables not specifically covered by the standards for appliances;
d) all consumer installations external to buildings;
e) fixed wiring for information and communication technology, signalling, control and the like
(excluding internal wiring of apparatus);
f) the extension or alteration of the installation and also parts of the existing installation
affected by the extension or alteration.
NOTE The rules of IEC 60364-1 are intended to apply to electrical installations generally but, in certain cases,
they may need to be supplemented by the requirements or recommendations of other IEC standards (for example,
for installations in explosive gas atmospheres).
11.3 IEC 60364-1 does not apply to
a) electric traction equipment, including rolling stock and signaling equipment;
b) electrical equipment of motor vehicles, except those covered in Part 7;
c) electrical installations on board ships and mobile and fixed offshore platforms;
d) electrical installations in aircraft;
e) public street-lighting installations which are part of the public power grid;
f) installations in mines and quarries;
g) radio interference suppression equipment, except where it affects the safety of the
installation;
h) electric fences;
i) external lightning protection systems for buildings (LPS);
NOTE Atmospheric phenomena are covered in IEC 60364-1 but only insofar as effects on the electrical
installations are concerned (for example, with respect to selection of surge protective devices).
j) certain aspects of lift installations;
k) electrical equipment of machines.
11.4 IEC 60364-1 is not intended to apply to
– systems for distribution of energy to the public, or
– power generation and transmission for such systems.
NOTE 1 Countries wishing to do so may, however, use this standard in whole or in part for that purpose.
NOTE 2 According to IEC 61936 which provides common rules for the design and the erection of electrical power
installations in systems with nominal voltages above 1kV a.c. and nominal frequency up to and including 60 Hz,
low- voltage a.c. and d.c. protection and monitoring systems should be in accordance with IEC 60364 series.
11.5 Electrical equipment is dealt with only so far as its selection and application in the
installation are concerned.
This applies also to assemblies of electrical equipment complying with the relevant standards.

60364-1  IEC:2005 – 17 –
12 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60038, IEC standard voltages
IEC 60050(691), International Electrotechnical Vocabulary (IEV) – Chapter 691: Tariffs for
electricity
IEC 60050-826, International Electrotechnical Vocabulary (IEV) – Part 826: Electrical
installations
IEC 60364-4-41, Electrical installations of buildings – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-4-42, Electrical installations of buildings – Part 4-42: Protection for safety –
Protection against thermal effects
IEC 60364-4-43, Electrical installations of buildings – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-4-44, Electrical installations of buildings – Part 4-44: Protection for safety –
Protection against voltage disturbances and electromagnetic disturbances
IEC 60364-5-51, Electrical installations of buildings – Part 5-51: Selection and erection of
electrical equipment – Common rules
IEC 60364-5-52, Electrical installations of buildings – Part 5-52: Selection and erection of
electrical equipment – Wiring systems
IEC 60364-5-53:2001, Electrical installations of buildings – Part 5-53: Selection and erection
of electrical equipment – Isolation, switching and control
IEC 60364-5-54, Electrical installations of buildings – Part 5-54: Selection and erection of
electrical equipment – Earthing arrangements, protective conductors and protective bonding
conductors
IEC 60364-5-55:2001, Electrical installations of buildings – Part 5-55: Selection and erection
of electrical equipment – Other equipment
IEC 60445, Basic and safety principles for man-machine interface, marking and identification -
Identification of equipment terminals and of terminations of certain designated conductors,
including general rules for an alphanumeric system
IEC 60446, Basic and safety principles for man-machine interface, marking and identification
– Identification of conductors by colours or numerals
IEC 60617-DB:2001 , Graphical symbols for diagrams
IEC 60721 (all parts), Classification of environmental conditions
—————————
″DB″ refers to the IEC on-line database.

60364-1  IEC:2005 – 19 –
13 Fundamental principles
NOTE 1 Where countries not yet having national regulations for electrical installations deem it necessary to
establish legal requirements for this purpose, it is recommended that such requirements be limited to fundamental
principles which are not subject to frequent modification on account of technical development. The contents of
Clause 13 may be used as a basis for such legislation.
NOTE 2 This clause contains basic requirements. In other parts of this standard (see Table A.2), more detailed
requirements may be given.
131 Protection for safety
131.1 General
The requirements stated in 131.2 to 131.7 are intended to provide for the safety of persons,
livestock and property against dangers and damage which may arise in the reasonable use of
electrical installations. The requirements to provide for the safety of livestock are applicable in
locations intended for them.
NOTE In electrical installations, the following hazards may arise:
– shock currents;
– excessive temperatures likely to cause burns, fires and other injurious effects;
– ignition of a potentially explosive atmosphere;
– undervoltages, overvoltages and electromagnetic influences likely to cause or result in injury or
damage;
– power supply interruptions and/or interruption of safety services;
– arcing, likely to cause blinding effects, excessive pressure, and/or toxic gases;
– mechanical movement of electrically activated equipment.
131.2 Protection against electric shock
131.2.1 Basic protection (protection against direct contact)
NOTE For low-voltage installations, systems and equipment, basic protection generally corresponds to protection
against direct contact.
Protection shall be provided against dangers that may arise from contact with live parts of the
installation by persons or livestock.
This protection can be achieved by one of the following methods:
– preventing a current from passing through the body of any person or any livestock;
– limiting the current which can pass through a body to a non-hazardous value.
131.2.2 Fault protection (protection against indirect contact)
NOTE For low-voltage installations, systems and equipment, fault protection generally corresponds to protection
against indirect contact, mainly with regard to failure of basic insulation.
Protection shall be provided against dangers that may arise from contact with exposed-
conductive-parts of the installation by persons or livestock.

60364-1  IEC:2005 – 21 –
This protection can be achieved by one of the following methods:
– preventing a current resulting from a fault from passing through the body of any person or
any livestock;
– limiting the magnitude of a current resulting from a fault, which can pass through a body,
to a non-hazardous value;
– limiting the duration of a current resulting from a fault, which can pass through a body, to
a non-hazardous time period.
131.3 Protection against thermal effects
The electrical installation shall be so arranged to minimize the risk of damage or ignition of
flammable materials due to high temperature or electric arc. In addition, during normal
operation of the electrical equipment, there shall be no risk of persons or livestock suffering
burns.
131.4 Protection against overcurrent
Persons and livestock shall be protected against injury and property shall be protected
against damage due to excessive temperatures or electromechanical stresses caused by any
overcurrents likely to arise in conductors.
Protection can be achieved by limiting the overcurrent to a safe value or duration.
131.5 Protection against fault currents
Conductors, other than live conductors, and any other parts intended to carry a fault current
shall be capable of carrying that current without attaining an excessive temperature.
Electrical equipment, including conductors shall be provided with mechanical protection
against electromechanical stresses of fault currents as necessary to prevent injury or damage
to persons, livestock or property.
Live conductors shall be protected against overcurrents arising from faults by the methods in
131.4.
NOTE Particular attention should be given to PE conductor and earthing conductor currents.
131.6 Protection against voltage disturbances and measures against
electromagnetic influences
131.6.1 Persons and livestock shall be protected against injury and property shall be
protected against any harmful effects as a consequence of a fault between live parts of
circuits supplied at different voltages.
131.6.2 Persons and livestock shall be protected against injury and property shall be
protected against damage as a consequence of overvoltages such as those originating from
atmospheric events or from switching.
NOTE For protection against direct lightning strikes, see IEC 62305 series.
131.6.3 Persons and livestock shall be protected against injury and property shall be
protected against damage as a consequence of undervoltage and any subsequent voltage
recovery.
60364-1  IEC:2005 – 23 –
131.6.4 The installation shall have an adequate level of immunity against electromagnetic
disturbances so as to function correctly in the specified environment. The installation design
shall take into consideration the anticipated electromagnetic emissions, generated by the
installation or the installed equipment, which shall be suitable for the current-using equipment
used with, or connected to, the installation.
131.7 Protection against power supply interruption
Where danger or damage is expected to arise due to an interruption of supply, suitable
provisions shall be made in the installation or installed equipment.
132 Design
132.1 General
For the design of the electrical installation, the following factors shall be taken into account to
provide
– the protection of persons, livestock and property in accordance with Clause 131;
– the proper functioning of the electrical installation for the intended use.
The information required as a basis for design is listed in 132.2 to 132.5. The requirements
with which the design shall comply are stated in 132.6 to 132.12.
132.2 Characteristics of available supply or supplies
When designing electrical installations in accordance with IEC 60364 series it is necessary to
know the characteristics of the supply. Relevant information from the network operator is
necessary to design a safe installation according to IEC 60364 series. The characteristics of
the power supply should be included in the documentation to show conformity with IEC 60364
series. If the network operator changes the characteristics of the power supply this may affect
the safety of the installation.
132.2.1 Nature of current: a.c. and/or d.c.
132.2.2 Function of conductors:
– for a.c.: line conductor(s);
neutral conductor;
protective conductor.
– for d.c.: line conductor(s);
midpoint conductor;
protective conductor.
NOTE The function of some conductors may be combined in a single conductor.
132.2.3 Values and tolerances:
– voltage and voltage tolerances;
– voltage interruptions, voltage fluctuations and voltage dips;
– frequency and frequency tolerances;

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– maximum current allowable;
– earth fault loop impedance upstream of the origin of the installation;
– prospective short-circuit currents.
For standard voltages and frequencies, see IEC 60038.
132.2.4 Protective provisions inherent in the supply, for example, system earthing or mid-
point earthing.
132.2.5 Particular requirements of the supply undertaking.
132.3 Nature of demand
The number and type of circuits required for lighting, heating, power, control, signalling,
information and communication technology, etc. shall be determined by
– location of points of power demand;
– loads to be expected on the various circuits;
– daily and yearly variation of demand;
– any special conditions such as harmonics;
– requirements for control, signalling, information and communication technology, etc;
– anticipated future demand if specified.
132.4 Electric supply systems for safety services or standby electric supply
systems
– Source of supply (nature, characteristics).
– Circuits to be supplied by the electric source for safety services or the standby electrical
source.
132.5 Environmental conditions
The design of the electrical installation shall take into account the environmental conditions to
which it will be subjected, see IEC 60364-5-51 and IEC 60721.
132.6 Cross-sectional area of conductors
The cross-sectional area of conductors shall be determined for both normal operating
conditions and for fault conditions according to
a) their admissible maximum temperature;
b) the admissible voltage drop;
c) the electromechanical stresses likely to occur due to earth fault and short-circuit currents;
d) other mechanical stresses to which the conductors can be subjected;
e) the maximum impedance with respect to the functioning of the protection against fault
currents;
f) the method of installation.
NOTE The items listed above concern primarily the safety of electrical installations. Cross-sectional areas greater
than those required for safety may be desirable for economic operation.

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132.7 Type of wiring and methods of installation
For the choice of the type of wiring and the methods of installation the following shall be taken
into account:
– the nature of the locations;
– the nature of the walls or other parts of the building supporting the wiring;
– accessibility of wiring to persons and livestock;
– voltage;
– the electromagnetic stresses likely to occur due to earth fault and short-circuit currents;
– electromagnetic interference;
– other stresses to which the wiring can be subjected during the erection of the electrical
installation or in service.
132.8 Protective equipment
The characteristics of protective equipment shall be determined with respect to their function
which may be, for example, protection against the effects of
– overcurrent (overload, short-circuit);
– earth fault current;
– overvoltage;
– undervoltage and no voltage.
The protective devices shall operate at values of current, voltage and time which are suitably
related to the characteristics of the circuits and to the possibilities of danger.
132.9 Emergency control
Where, in case of danger, there is the necessity for the immediate interruption of supply, an
interrupting device shall be installed in such a way that it can be easily recognized and
effectively and rapidly operated.
132.10 Disconnecting devices
Disconnecting devices shall be provided so as to permit switching and/or isolation of the
electrical installation, circuits or individual items of apparatus as required for operation,
inspection and fault detection, testing, maintenance and repair.
132.11 Prevention of mutual detrimental influence
The electrical installation shall be arranged in such a way that no mutual detrimental influence
will occur between electrical installations and non-electrical installations.
132.12 Accessibility of electrical equipment
The electrical equipment shall be arranged so as to afford as may be necessary:
– sufficient space for the initial installation and later replacement of individual items of
electrical equipment;
– accessibility for operation, inspection and fault detection, testing, maintenance and repair.

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132.13 Documentation for the electrical installation
Every electrical installation shall be provided with appropriate documentation.
133 Selection of electrical equipment
133.1 General
Every item of electrical equipment used in electrical installations shall comply with such
IEC standards as are appropriate. In the absence of an IEC standard the equipment shall
comply with the appropriate national standards. Where there are no applicable standards, the
item of equipment concerned shall be selected by special agreement between the person
specifying the installation and the installer.
133.2 Characteristics
Every item of electrical equipment selected shall have suitable characteristics appropriate to
the values and conditions on which the design of the electrical installation (see Clause 132) is
based and shall, in particular, fulfil the following requirements.
133.2.1 Voltage
Electrical equipment shall be suitable with respect to the maximum steady-state voltage
(r.m.s. value for a.c.) likely to be applied, as well as overvoltages likely to occur.
NOTE For certain equipment, it may be necessary to take account of the lowest voltage likely to occur.
133.2.2 Current
All electrical equipment shall be selected with respect to the maximum steady-state current
(r.m.s. value for a.c.) which it has to carry in normal service, and with respect to the current
likely to be carried in abnormal conditions and the period (for example, operating time of
protective devices, if any) during which it may be expected to flow.
133.2.3 Frequency
If frequency has an influence on the characteristics of electrical equipment, the rated
frequency of the equipment shall correspond to the frequency likely to occur in the circuit.
133.2.4 Load factor
All electrical equipment which is selected on the basis of its power characteristics shall be
suitable for the duty demanded of the equipment taking into account the design service
conditions, see IEV 691-10-02.
133.3 Conditions of installation
All electrical equipment shall be selected so as to withstand safely the stresses and the
environmental conditions (see 132.5) characteristic of its location and to which it may be
subjected. If, however, an item of equipment does not have by design the properties
corresponding to its location, it may be used on condition that adequate additional protection
is provided as part of the completed electrical installation.

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133.4 Prevention of harmful effects
All electrical equipment shall be selected so that it will not cause harmful effects on other
equipment or impair the supply during normal service including switching operations. In this
context, the factors which can have an influence include, for example:
– power factor;
– inrush current;
– asymmetrical load;
– harmonics;
– transient overvoltages generated by equipment in the installation.
134 Erection and verification of electrical installations
134.1 Erection
134.1.1 Good workmanship by competent persons and proper materials shall be used in the
erection of the electrical installation. Electrical equipment shall be installed in accordance with
the instructions provided by the manufacturer of the equipment.
134.1.2 The characteristics of the electrical equipment, as determined in accordance with
Clause 133, shall not be impaired during erection.
134.1.3 Conductors shall be identified in accordance with IEC 60446. Where identification of
terminals is necessary, they shall be identified in accordance with IEC 60445.
134.1.4 Connections between conductors and between conductors and other electrical
equipment shall be made in such a way that safe and reliable contact is ensured.
134.1.5 All electrical equipment shall be installed in such a manner that the designed heat
dissipation conditions are not impaired.
134.1.6 All electrical equipment likely to cause high temperatures or electric arcs shall be
placed or guarded so as to minimize the risk of ignition of flammable materials. Where the
temperature of any exposed parts of electrical equipment is likely to cause injury to persons,
those parts shall be so located or guarded as to prevent accidental contact therewith.
134.1.7 Where necessary for safety purposes, suitable warning signs and/or notices shall be
provided.
134.1.8 Where an installation is erected by using new materials, inventions or methods
leading to deviations from the rules of IEC 60364 series, the resulting degree of safety of the
installation shall not be less than that obtained by compliance with IEC 60364 series.
134.1.9 In the case of an addition or alteration to an existing installation, it shall be
determined that the rating and condition of existing equipment, which will have to carry any
additional load, is adequate for the altered circumstances. Furthermore, the earthing and
bonding arrangements, if necessary for the protective measure applied for the safety of the
addition or alteration, shall be adequate.

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134.2 Initial verification
Electrical installations shall be verified before being placed in service and after any important
modification to confirm proper execution of the work in accordance with this standard.
134.3 Periodic verification
It is recommended that every electrical installation is subjected to periodic verification.
20 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050-826 apply. For
further explanations to several terms of IEV 826, see Annex B.
30 Assessment of general characteristics
An assessment shall be made of the following characteristics of the installation in accordance
with the clauses indicated:
– the purposes for which the installation is intended to be used, its general structure and its
supplies (Clauses 31, 35 and 36);
– the external influences to which it is to be exposed (Clause 32);
– the compatibility of its equipment (Clause 33);
– its maintainability (Clause 34).
Those characteristics shall be taken into account in the choice of methods of protection for
safety (see IEC 60364-4-41 to IEC 60364-4-44) and the selection and erection of equipment
(see IEC 60364-5-51 to IEC 60364-5-55).
NOTE For other types of installation, for example, for telecommunication installations or Home and Building
Electronic Systems (HBES) etc., account should be taken of IEC standards relevant to the type of installation
concerned. For telecommunication installations, also the publications of the ITU-T and ITU-R are to be taken into
account.
31 Purposes, supplies and structure
311 Maximum demand and diversity
For economic and reliable design of an installation within thermal and voltage drop limits, a
determination
...