General rules of electrical installation design

427 Pages·2006·11.39 MB·English

Technical Series
Electrical
installation guide
According to IEC International Standards
2008
http://theguide.schneider-electric.com

This guide has been written for electrical Engineers who have to
design, realize, inspect or maintain electrical installations in compliance
with international Standards of the International Electrotechnical
Commission (IEC).
“Which technical solution will guarantee that all relevant safety rules are
met?” This question has been a permanent guideline for the elaboration of
this document.
An international Standard such as the IEC 60364 “Electrical Installation
in Buldings” specifies extensively the rules to comply with to ensure
safety and predicted operational characteristics for all types of electrical
installations. As the Standard must be extensive, and has to be applicable
to all types of products and the technical solutions in use worldwide, the
text of the IEC rules is complex, and not presented in a ready-to-use order.
The Standard cannot therefore be considered as a working handbook, but
only as a reference document.
The aim of the present guide is to provide a clear, practical and step-
by-step explanation for the complete study of an electrical installation,
according to IEC 60364 and other relevant IEC Standards. Therefore, the
first chapter (B) presents the methodology to be used, and each chapter
deals with one out of the eight steps of the study. The two last chapter are
devoted to particular supply sources, loads and locations, and appendix
provides additional information. Special attention must be paid to the
EMC appendix, which is based on the broad and practical experience on
electromagnetic compatibility problems.
We all hope that you, the user, will find this handbook genuinely helpful.
Schneider Electric S.A.
This technical guide is the result of The Electrical Installation Guide is a single document covering the
a collective effort. techniques, regulations and standards related to electrical installations.
It is intended for electrical professionals in companies, design offices,
Technical advisor:
inspection organisations, etc.
Serge Volut - Jacques Schonek
Illustrations and production: This Technical Guide is aimed at professional users and is only intended
AXESS - Valence -France to provide them guidelines for the definition of an industrial, tertiary or
domestic electrical installation. Information and guidelines contained in this
Printing:
Guide are provided AS IS. Schneider Electric makes no warranty of any
Les Deux-Ponts - France
kind, whether express or implied, such as but not limited to the warranties
Edition of merchantability and fitness for a particular purpose, nor assumes any
March 2008 legal liability or responsibility for the accuracy, completeness, or usefulness
of any information, apparatus, product, or process disclosed in this Guide,
Price: 90 �
nor represents that its use would not infringe privately owned rights.
The purpose of this guide is to facilitate the implementation of International
ISBN: 978.2.9531643.0.5
installation standards for designers & contractors, but in all cases the
N° dépôt légal: 1er semestre 2008
original text of International or local standards in force shall prevail.
© Schneider Electric
This new edition has been published to take into account changes in
All rights reserved in all countries
techniques, standards and regulations, in particular electrical installation
standard IEC 60364.
We thank all the readers of the previous edition of this guide for their
comments that have helped improve the current edition.
We also thank the many people and organisations, to numerous to name
here, who have contributed in one way or another to the preparation of this
guide.
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Drawing source files for
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Schneider Electric - Electrical installation guide 2008 Schneider Electric - Electrical installation guide 2008
Guiding tools for more efficiency in electrical
distribution design
Technical knowledge Pre-design help for budget Design support Specification help Help in installation, use &
approach maintenance
10-30mn eLearning modules for Selection criterias & method Practical data & methods Technical specification on Product installation data
individual training to follow in order to pre-define through major design guides: products & solutions for tender
project specification: b Electrical Installation Guide request Product how to use data
Articles giving base skills about b Architecture guide b Protection guide
general subjects: “Cahiers b ID-Spec software b Industrial electrical network Product maintenance data
Techniques” design guide
b ...
Product presentation of technical
characteristics in all Schneider
Electric product Catalogues
Design Software:

b My Ecodial
Ecodial software provides a
complete design package for
Solutions and examples with
LV installations, in accordance
recommended architectures in
with IEC standards and
Solution guides:
recommendations.
b airport
Main features:
b automative
v Create diagrams
b food
v Optimise circuit breakers curves
b retail v Determine source power
b office v Follow step by step calculation
b industrial buildings v Print the project design file
b healthcare b SISPRO building
b ... b ...

Drawing source files for
connection, dimension, diagram,
mounting & safety: CAD library
Schneider Electric - Electrical installation guide 2008 Schneider Electric - Electrical installation guide 2008
General rules of electrical A
installation design
Connection to the MV utility B
distribution network
Connection to the LV utility C
distribution network
MV & LV architecture selection D
guide
LV Distribution E
Protection against electric F
shocks
Sizing and protection of G
conductors
LV switchgear: functions & H
selection
Protection against voltage J
surges in LV
Energy Efficiency in electrical K
distribution
Power factor correction and L
harmonic filtering
Harmonic management M
Characteristics of particular N
sources and loads
Residential and other special P
locations
EMC guidelines Q
General contents
A General rules of electrical installation design
1 Methodology A2
2 Rules and statutory regulations A4
3 Installed power loads - Characteristics A10
4 Power loading of an installation A15
B Connection to the MV utility distribution network
1 Supply of power at medium voltage B2
2 Procedure for the establishment of a new substation B14
3 Protection aspect B16
4 The consumer substation with LV metering B22
5 The consumer substation with MV metering B30
6 Constitution of MV/LV distribution substations B35
C Connection to the LV utility distribution network
1 Low voltage utility distribution networks C2
2 Tariffs and metering C16
D MV & LV architecture selection guide
1 Stakes for the user D3
2 Simplified architecture design process D4
3 Electrical installation characteristics D7
4 Technological characteristics D11
5 Architecture assessment criteria D13
6 Choice of architecture fundamentals D15
7 Choice of architecture details D19
8 Choice of equiment D24
9 Recommendations for architecture optimization D26
10 Glossary D29
11 ID-Spec software D30
12 Example: electrical installation in a printworks D31
E LV Distribution
1 Earthing schemes E2
2 The installation system E15
3 External influences (IEC 60364-5-51) E25
F Protection against electric shocks
1 General F2
2 Protection against direct contact F4
3 Protection against indirect contact F6
4 Protection of goods due to insulation fault F17
5 Implementation of the TT system F19
6 Implementation of the TN system F25
7 Implementation of the IT system F31
8 Residual current differential devices RCDs F38
G Sizing and protection of conductors
1 General G2
2 Practical method for determining the smallest allowable G7
cross-sectional area of circuit conductors
3 Determination of voltage drop G20
4 Short-circuit current G24
5 Particular cases of short-circuit current G30
6 Protective earthing conductor G37
7 The neutral conductor G42
8 Worked example of cable calculation G46
H LV switchgear: functions & selection
1 The basic functions of LV switchgear H2
2 The switchgear H5
3 Choice of switchgear H10
4 Circuit breaker H11
Schneider Electric - Electrical installation guide 2008
General contents
J Protection against voltage surges in LV
1 General J2
2 Overvoltage protection devices J6
3 Standards J11
4 Choosing a protection device J14
K Energy Efficiency in electrical distribution
1 Introduction K2
2 Energy efficiency and electricity K3
3 One process, several players K5
4 From electrical measurement to electrical information K10
5 Communication and Information System K16
L Power factor correction and harmonic filtering
1 Reactive energy and power factor L2
2 Why to improve the power factor? L5
3 How to improve the power factor? L7
4 Where to install power correction capacitors? L10
5 How to decide the optimum level of compensation? L12
6 Compensation at the terminals of a transformer L15
7 Power factor correction of induction motors L18
8 Example of an installation before and after power factor correction L20
9 The effects of harmonics L21
10 Implementation of capacitor banks L24
M Harmonic management
1 The problem: M2
Why is it necessary to detect and eliminate harmonics?
2 Standards M3
3 General M4
4 Main effects of harmonics in installations M6
5 Essential indicators of harmonic distortion and M11
measurement principles
6 Measuring the indicators M14
7 Detection devices M16
8 Solutions to attenuate harmonics M17
N Characteristics of particular sources and loads
1 Protection of a LV generator set and the downstream circuits N2
2 Uninterruptible Power Supply Units (UPS) N11
3 Protection of LV/LV transformers N24
4 Lighting circuits N27
5 Asynchronous motors N42
P Residential and other special locations
1 Residential and similar premises P2
2 Bathrooms and showers P8
3 Recommendations applicable to special installations and locations P12
Q EMC guidelines
1 Electrical distribution Q2
2 Earthing principles and structures Q3
3 Implementation Q5
4 Coupling mechanism and counter-measures Q14
5 Wiring recommendations Q20
Schneider Electric - Electrical installation guide 2008
Chapter A
General rules of electrical
installation design A
Contents

Methodology A2

2 Rules and statutory regulations A4
2.1 Definition of voltage ranges A4
2.2 Regulations A5
2.3 Standards A5
2.4 Quality and safety of an electrical installation A6
2.5 Initial testing of an installation A6
2.6 Periodic check-testing of an installation A7
2.7 Conformity (with standards and specifications) of equipment
used in the installation A7
2.8 Environment A8
3 Installed power loads - Characteristics A0
3.1 Induction motors A10
3.2 Resistive-type heating appliances and incandescent lamps
(conventional or halogen) A12
4 Power loading of an installation A5
4.1 Installed power (kW) A15
4.2 Installed apparent power (kVA) A15
4.3 Estimation of actual maximum kVA demand A16
4.4 Example of application of factors ku and ks A17
4.5 Diversity factor A18
4.6 Choice of transformer rating A19
4.7 Choice of power-supply sources A20
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Schneider Electric - Electrical installation guide 2008
A - General rules of electrical installation design  Methodology
A2
For the best results in electrical installation design it is recommended to read all the
chapters of this guide in the order in which they are presented.
Listing of power demands
A - General rules of electrical installation design The study of a proposed electrical installation requires an adequate understanding of
all governing rules and regulations.
The total power demand can be calculated from the data relative to the location and
power of each load, together with the knowledge of the operating modes (steady
state demand, starting conditions, non simultaneous operation, etc.)
From these data, the power required from the supply source and (where appropriate)
the number of sources necessary for an adequate supply to the installation are
readily obtained.
Local information regarding tariff structures is also required to allow the best choice
of connection arrangement to the power-supply network, e.g. at medium voltage or
low voltage level.
Service connection
This connection can be made at:
B – Connection to the MV utility distribution b Medium Voltage level
network A consumer-type substation will then have to be studied, built and equipped. This
substation may be an outdoor or indoor installation conforming to relevant standards
and regulations (the low-voltage section may be studied separately if necessary).
Metering at medium-voltage or low-voltage is possible in this case.
C - Connection to the LV utility distribution b Low Voltage level
network The installation will be connected to the local power network and will (necessarily) be
metered according to LV tariffs.
D - MV & LV architecture selection guide Electrical Distribution architecture
The whole installation distribution network is studied as a complete system.
A selection guide is proposed for determination of the most suitable architecture.
MV/LV main distribution and LV power distribution levels are covered.
E - LV Distribution Neutral earthing arrangements are chosen according to local regulations, constraints
related to the power-supply, and to the type of loads.
The distribution equipment (panelboards, switchgears, circuit connections, ...) are
determined from building plans and from the location and grouping of loads.
The type of premises and allocation can influence their immunity to external
disturbances.
F - Protection against electric shocks Protection against electric shocks
The earthing system (TT, IT or TN) having been previously determined, then the
appropriate protective devices must be implemented in order to achieve protection
against hazards of direct or indirect contact.
G - Sizing and protection of conductors Circuits and switchgear
Each circuit is then studied in detail. From the rated currents of the loads, the level
of short-circuit current, and the type of protective device, the cross-sectional area
of circuit conductors can be determined, taking into account the nature of the
cableways and their influence on the current rating of conductors.
Before adopting the conductor size indicated above, the following requirements must
be satisfied:
b The voltage drop complies with the relevant standard
b Motor starting is satisfactory
b Protection against electric shock is assured
The short-circuit current Isc is then determined, and the thermal and electrodynamic
withstand capability of the circuit is checked.
These calculations may indicate that it is necessary to use a conductor size larger
than the size originally chosen.
ed H - LV switchgear: functions & selection The performance required by the switchgear will determine its type and
v
eser characteristics.
hts r The use of cascading techniques and the discriminative operation of fuses and
g tripping of circuit breakers are examined.
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Schneider Electric - Electrical installation guide 2008