Download IEC Electrical-Installation Guide PDF

TitleIEC Electrical-Installation Guide
File Size2.7 MB
Total Pages380
Table of Contents
General - Installed power
	rules and statutory regulations
		definition of voltage ranges
			table B1 standard voltages between 100 V and 1000 V (IEC 38-1983)
			table B2 standard voltages above 1 kV and not exceeding 35 kV (IEC 38-1983)
		quality and safety of an electrical installation
		initial testing of an installation
		periodic check-testing of an installation
			table B3 frequency of check-tests commonly recommended for an electrical installation
		conformity (with standards and specifications) of equipment used in the installation
	motor, heating and lighting loads
		induction motors
			table B4 power and current values for typical induction motors
		direct-current motors
			table B6 progressive starters with voltage ramp
			table B7 progressive starters with current limitation
		resistive-type heating appliances and incandescent lamps (conventional or halogen)
			table B8 current demands of resistive heating and incandescent lighting (conventional or halogen) appliances
		fluorescent lamps and related equipment
			table B10 current demands and power consumption of commonly-dimensioned fluorescent lighting tubes (at 220 V/240 V - 50 Hz)
			table B11 current demands and power consumption of compact fluorescent lamps (at 220 V/240 V - 50 Hz)
		discharge lamps
			table B12 current demands of discharge lamps
	power loading of an installation
		installed power (kW)
		installed apparent power (kVA)
			table B13 estimation of installed apparent power
		estimation of actual maximum kVA demand
			table B14 simultaneity factors in an apartment block
			table 16 factor of simultaneity for distribution boards (IEC 439)
			table 17 factor of simultaneity according to circuit function
			table 18 an example in estimating the maximum predicted loading of an installation
		diversity factor
		choice of transformer rating
			table B19 IEC-standardized kVA ratings of HV/LV 3-phase distribution transformers and corresponding nominal full-load current values
		choice of power-supply sources
HV/LV distribution substations
	supply of power at high voltage
		power-supply characteristics of high voltage distribution networks
			table C1 relating nominal system voltages with corresponding rated system voltages (r.m.s. values)
			table C2 switchgear rated insulation levels
			table C3A transformers rated insulation levels in series I (based on current practice other than in the United States of America and some other countries)
			table C3B transformers rated insulation levels in series II (based on current practice in the United States of America and some other countries)
			table C4 standard short-circuit current-breaking ratings extracted from table X IEC 56
		different HV service connections
		some operational aspects of HV distribution networks
	consumers HV substations
		procedures for the establishment of a new substation
	substation protection schemes
		protection against electric shocks and overvoltages
		electrical protection
			table C18 power limits of transformers with a maximum primary current not exceeding 45 A
			table C19 rated current (A) of HV fuses for transformer protection according to IEC 282-1
			table C20 3-phase short-circuit currents of typical distribution transformers
		protection against thermal effects
		interlocks and conditioned man.uvres
	the consumer substation with LV metering
		choice of panels
			table C27 standard short-circuit MVA and current ratings at different levels of nominal voltage
		choice of HV switchgear panel for a transformer circuit
		choice of HV/LV transformer
			table C31 categories of dielectric fluids
			table C32 safety measures recommended in electrical installations using dielectric liquids of classes 01, K1, K2 or K3
	a consumer substation with HV metering
		choice of panels
		parallel operation of transformers
	constitution of HV/LV distribution substations
		different types of substation
		indoor substations equipped with metal-enclosed switchgear
		outdoor substations
	appendix 1 : example in coordination of the characteristics of an HV switch-fuse combination protecting an HV/LV transformer
		transfert current and take-over current
		types of faults involved in the transfer region
	appendix 2 : ground-surface potential gradients due to earth-fault currents
	appendix 3 : vector diagram of ferro-resonance at 50Hz (or 60 Hz)
Low-voltage service connections
	low-voltage public distribution networks
		low-voltage consumers
			table D1 survey of electricity supplies in various countries around the world.
		1.2 LV distribution networks
		the consumer-service connection
		quality of supply voltage
	tariffs and metering
Power factor improvement and harmonic filtering
	power factor improvement
		the nature of reactive energy
		plant and appliances requiring reactive current
		the power factor
		tan o
		practical measurement of power factor
		practical values of power factor
			table E5 example in the calculation of active and reactive power
			table E7 values of cos  and tan  for commonly-used plant and equipment E
	why improve the power factor?
		reduction in the cost of electricity
		technical/economic optimization
			table E8 multiplying factor for cable size as a function of cos o
	how to improve the power factor
		theoretical principles
		by using what equipment?
		the choice between a fixed or automatically-regulated bank of capacitors
	where to install correction capacitors
		global compensation
		compensation by sector
		individual compensation
	how to decide the optimum level of compensation
		general method
		simplified method
			table E17 kvar to be installed per kW of load, to improve the power factor of an installation
		method based on the avoidance of tariff penalties
		method based on reduction of declared maximum apparent power (kVA)
	compensation at the terminals of a transformer
		compensation to increase the available active power output
			table E20 active-power capability of fully-loaded transformers, when supplying loads at different values of power factor
		compensation of reactive energy absorbed by the transformer
			table E24 reactive power consumption of distribution transformers with 20 kV primary windings
	compensation at the terminals of an induction motor
		connection of a capacitor bank and protection settings
			table E26 reduction factor for overcurrent protection after compensation
		how self-excitation of an induction motor can be avoided
			table E28 maximum kvar of P.F. correction applicable to motor terminals without risk of self-excitation
	example of an installation before and after power-factor correction
	the effect of harmonics on the rating of a capacitor bank
		problems arising from power-system harmonics
		possible solutions
		choosing the optimum solution
			table E30 choice of solutions for limiting harmonics associated with a LV capacitor bank
		possible effects of power-factor-correction capacitors on the power-supply system
	implementation of capacitor banks
		capacitor elements
		choice of protection, control devices, and connecting cables
	appendix 1 : elementary harmonic filters
	appendix 2 : harmonic suppression reactor for a single (power factor correction) capacitor bank
Distribution within a low-voltage installation
		the principal schemes of LV distribution
		the main LV distribution board
		transition from IT to TN
	essential services standby supplies
		continuity of electric-power supply
		quality of electric-power supply
			table F10 assumed levels of transient overvoltage possible at different points of a typical installation
			table F12 typical levels of impulse withstand voltage of industrial circuit breakers labelled Uimp = 8 kV
			table F18 compatibility levels for installation materials
	safety and emergency-services installations, and standby power supplies
		safety installations
		standby reserve-power supplies
		choice and characteristics of reserve-power supplies
			table F21 table showing the choice of reserve-power supply types according to application requirements and acceptable supply-interruption times
		choice and characteristics of different sources
			table F22 table of characteristics of different sources
		local generating sets
	earthing schemes
		earthing connections
			table F25 list of exposed-conductive-parts and extraneous-conductive-parts
		definition of standardized earthing schemes
		earthing schemes characteristics
		choice criteria
		comparison for each criterion
		choice of earthing method - implementation
		installation and measurements of earth electrodes
			table F47 resistivity (-m) for different kinds of terrainF
			table F48 mean values of resistivity (-m) for an approximate estimation of an earth-electrode resistance with respect to zero-potential earth
	distribution boards
		types of distribution board
		the technologies of functional distribution boards
		centralized control
		description and choice
		conduits, conductors and cables
			table F60 selection of wiring systems
			table F61 erection of wiring systems
			table F62 some examples of installation methods
			table F63 designation code for conduits according to the most recent IEC publications
			table F64 designation of conductors and cables according to CENELEC code for harmonized cables
			table F66 commonly used conductors and cables
	external influences
			table F67 concise list of important external influences (taken from Appendix A of IEC 364-3)
		protection by enclosures: IP code
Protection against electric shocks
		electric shock
		direct and indirect contact
	protection against direct contact
		measures of protection against direct contact
		additional measure of protection against direct contact
	protection against indirect contact
		measure of protection by automatic disconnection of the supply
			table G8 maximum safe duration of the assumed values of touch voltage in conditions where UL = 50 V
			table G9 maximum safe duration of the assumed values of touch voltage in conditions where UL  25 V
		automatic disconnection for a TT-earthed installation
			table G11 maximum operating times of RCCBs (IEC 1008)
		automatic disconnection for a TN-earthed installation
			table G13 maximum disconnection times specified for TN earthing schemes (IEC 364-4-41)
		automatic disconnection on a second earth fault in an IT-earthed system
			table G18 maximum disconnection times specified for an IT-earthed installation (IEC 364-4-41)
		measures of protection against direct or indirect contact without circuit disconnection
	implementation of the TT system
		protective measures
			table G26 the upper limit of resistance for an installation earthing electrode which must not be exceeded, for given sensitivity levels of RCDs at UL voltage limits of 50 V and 25 V
		types of RCD
		coordination of differential protective devices
	implementation of the TN system
		preliminary conditions
		protection against indirect contact
			table G42 correction factor to apply to the lengths given in tables G43 to G46 for TN systems
			table G43 maximum circuit lengths for different sizes of conductor and instantaneous-tripping-current settings for general-purpose circuit breakers
			table G44 maximum circuit lengths for different sizes of conductor and rated currents for type B circuit breakers
			table G45 maximum circuit lengths for different conductor sizes and for rated currents of circuit breakers of type C
			table G46 maximum circuit lengths for different conductor sizes and for rated currents of circuit breakers of type D or MA Merlin Gerin
		high-sensitivity RCDs
		protection in high fire-risk locations
		when the fault-current-loop impedance is particularly high
	implementation of the IT system
		preliminary conditions
			table G53 essential functions in IT schemes
		protection against indirect contact
			table G59 correction factors, for IT-earthed systems, to apply to the circuit lengths given in tables G43 to G46
		high-sensitivity RCDs
		in areas of high fire-risk
		when the fault-current-loop impedance is particularly high
	residual current differential devices (RCDs)
		application of RCDs
			tble G70 electromagnetic compatibility withstand-level tests for RCDs
			table G72 means of reducing the ratio In/lph (max.)G
		choice of characteristics of a residual-current circuit breaker (RCCB - IEC 1008)
			table G74 typical manufacturers coordination table for RCCBs, circuit breakers, and fuses
The protection of circuits and the switchgear
	H1. the protection of circuits
			methodology and definitions
				table H1-1 logigram for the selection of cable size and protective-device rating for a given circuit
			overcurrent protection principles
			practical values for a protection scheme
			location of protective devices
				table H1-7 general rules and exceptions concerning the location of protective devices
			cables in parallel
			worked example of cable calculations
				table H1-9 calculations carried out with ECODIAL software (Merlin Gerin)
				table H1-10 example of short-circuit current evaluation
		practical method for determining the smallest allowable cross-sectional-area of circuit conductors
				table H1-11 logigram for the determination of minimum conductor size for a circuit
			determination of conductor size for unburied circuits
				table H1-12 code-letter reference, depending on type of conductor and method of installation
				table H1-13 factor K1 according to method of circuit installation (for further examples refer to IEC 364-5-52 table 52H)
				table H1-14 correction factor K2 for a group of conductors in a single layer
				table H1-15 correction factor K3 for ambient temperature other than 30 CH
				table H1-17 case of an unburied circuit: determination of the minimum cable size (c.s.a.), derived from the code letter; conductor material; insulation material and the fictitious current I'z
			determination of conductor size for buried circuits
				table H1-19 correction factor K4 related to the method of installation
				table H1-20 correction factor K5 for the grouping of several circuits in one layer
				table H1-21 correction factor K6 for the nature of the soil
				table H1-22 correction factor K7 for soil temperatures different than 20 CH
				table H1-24 case of a buried circuit: minimum c.s.a. in terms of type of conductor; type of insulation; and value of fictitious current I'z (I'z =lz/k)
		determination of voltage drop
			maximum voltage-drop limit
				table H1-26 maximum voltage-drop limits
			calculation of voltage drops in steady load conditions
				table H1-28 voltage-drop formulae
				table H1-29 phase-to-phase voltage drop U for a circuit, in volts per ampere per kmH
		short-circuit current calculations
			short-circuit current at the secondary terminals of a HV/LV distribution transformer
				table H1-32 typical values of Usc for different kVA ratings of transformers with HV windings  20 kVH
				table H1-33 Isc at the LV terminals of 3-phase HV/LV transformers supplied from a HV system with a 3-phase fault level of 500 MVA, or 250 MVA
			3-phase short-circuit current (Isc) at any point within a LV installation
				table H1-36 the impedance of the HV network referred to the LV side of the HV/LV transformer
				table H1-37  resistance, reactance and impedance values for typical distribution transformers with HV windings  20 kVH
				table H1-38 recapitulation table of impedances for different parts of a power-supply system
				table H1-39 example of short-circuit current calculations for a LV installation supplied at 400 V (nominal) from a 1,000 kVA HV/LV transformer
			Isc at the receiving end of a feeder in terms of the Isc at its sending end
				table H1-40 Isc at a point downstream, in terms of a known upstream fault-current value and the length and c.s.a. of the intervening conductors, in a 230/400 V 3-phase system
			short-circuit current supplied by an alternator or an inverter
		particular cases of short-circuit current
			calculation of minimum levels of short-circuit current
				table H1-49 maximum circuit lengths in metres for copper conductors (for aluminium, the lengths must be multiplied by 0.62)
				table H1-50 maximum length of copper-conductored circuits in metres protected by B-type circuit breakers
				table H1-51 maximum length of copper-conductored circuits in metres protected by C-type circuit breakers
				table H1-52 maximum length of copper-conductored circuits in metres protected by D-type circuit breakers
				table H1-53 correction factors to apply to lengths obtained from tables H1-49 to H1-52
			verification of the withstand capabilities of cables under short-circuit conditions
				table H1-54 value of the constant k2
				table H1-55 maximum allowable thermal stress for cables (expressed in amperes2 x seconds x 106)
		protective earthing conductors (PE)
			connection and choice
				table H1-59 choice of protective conductors (PE)
			conductor dimensioning
				table H1-60 minimum c.s.a.'s for PE conductors and earthing conductors (to the installation earth electrode)
				table H1-61 k factor values for LV PE conductors, commonly used in national standards and complying with IEC 724
			protective conductor between the HV/LV transformer and the main general distribution board (MGDB)
				table H1-63 c.s.a. of PE conductor between the HV/LV transformer and the MGDB, in terms of transformer ratings and fault-clearance times used in France
			equipotential conductor
		the neutral conductor
			dimensioning the neutral conductor
			protection of the neutral conductor
				table H1-65 table of protection schemes for neutral conductors in different earthing systems
	H2. the switchgear
		the basic functions of LV switchgear
			table H2-1 basic functions of LV switchgear
			electrical protection
				table H2-2 peak value of impulse voltage according to normal service voltage of test specimen
			switchgear control
		the switchgear and fusegear
			elementary switching devices
				table H2-7 utilization categories of LV a.c. switches according to IEC 947-3
				table H2-8 factor "n" used for peak-to-rms value (IEC 947-part 1)
				table H2-13 zones of fusing and non-fusing for LV types gG and gM class fuses (IEC 269-1 and 269-2-1)
			combined switchgear elements
		choice of switchgear
			tabulated functional capabilities
				table H2-19 functions fulfilled by different items of switchgear
			switchgear selection
		circuit breakers
			table H2-20 functions performed by a circuit breaker/disconnector
			standards and descriptions
			fundamental characteristics of a circuit breaker
				table H2-28 tripping-current ranges of overload and short-circuit protective devices for LV circuit breakers
				table H2-31 Icu related to power factor (cos ) of fault-current circuit (IEC 947-2)H
			other characteristics of a circuit breaker
				table H2-34 relation between rated breaking capacity Icu and rated making capacity Icm at different power-factor values of short-circuit current, as standardized in IEC 947-2
			selection of a circuit breaker
				table H2-38 examples of tables for the determination of derating/uprating factors to apply to CBs with uncompensated thermal tripping units, according to temperature
				table H2-40 different tripping units, instantaneous or short-time delayed
				table H2-43 maximum values of short-circuit current to be interrupted by main and principal circuit breakers (CBM and CBP respectively), for several transformers in parallel
			coordination between circuit breakers
			discrimination HV/LV in a consumer's substation
Particular supply sources and loads
	protection of circuits supplied by an alternator
		an alternator on short-circuit
		protection of essential services circuits supplied in emergencies from an alternator
		choice of tripping units
		methods of approximate calculation
			table J1-7 procedure for the calculation of 3-phase short-circuit current
			table J1-8 procedure for the calculation of 1-phase to neutral short-circuit current
		the protection of standby and mobile a.c. generating sets
	inverters and UPS (Uninterruptible Power Supply units)
		what is an inverter?
		types of UPS system
			table J2-4 examples of different possibilities and applications of inverters, in decontamination of supplies and in UPS schemes
		choice of a UPS system
		UPS systems and their environment
		putting into service and technology of UPS systems
		earthing schemes
		choice of main-supply and circuit cables, and cables for the battery connection
			table J2-21 voltage drop in % of 324 V d.c. for a copper-cored cable
			table J2-22 currents and c.s.a. of copper-cored cables feeding the rectifier, and supplying the load for UPS system Maxipac (cable lengths < 100 m)
			table J2-23 currents and c.s.a. of copper-cored cables feeding the rectifier, and supplying the load for UPS system EPS 2000 (cable lengths < 100 m). Battery cable data are also included
			table J2-24 input, output and battery currents for UPS system EPS 5000 (Merlin Gerin)
		choice of protection schemes
		complementary equipments
	protection of LV/LV transformers
		transformer-energizing in-rush current
		protection for the supply circuit of a LV/LV transformer
		typical electrical characteristics of LV/LV 50 Hz transformers
			table J3-5 typical electrical characteristics of LV/LV 50 Hz transformers
		protection of transformers with characteristics as tabled in J3-5 above, using Merlin Gerin circuit breakers
			table J3-6protection of 3-phase LV/LV transformers with 400 V primary windings
			table J3-7 protection of 3-phase LV/LV transformers with 230 V primary windings
			table J3-8 protection of 1-phase LV/LV transformers with 400 V primary windings
			table J3-9 protection of 1-phase LV/LV transformers with 230 V primary windings
	lighting circuits
		service continuity
		lamps and accessories (luminaires)
			table J4-1 analysis of disturbances in fluorescent-lighting circuits
		the circuit and its protection
		determination of the rated current of the circuit breaker
			table J4-2 protective circuit breaker ratings for incandescent lamps and resistive-type heating circuits
			table J4-3 maximum limit of rated current per outgoing lighting circuit, for high-pressure discharge lamps
			table J4-4 current ratings of circuit breakers related to the number of fluorescent luminaires to be protected
		choice of control-switching devices
			table J4-5 types of remote control
		protection of ELV lighting circuits
		supply sources for emergency lighting
	asynchronous motors
		protective and control functions required
			table J5-2 commonly-used types of LV motor-supply circuits
		basic protection schemes: circuit breaker / contactor / thermal relay
			table J5-4 utilization categories for contactors (IEC 947-4)
		preventive or limitative protection
		maximum rating of motors installed for consumers supplied at LV
			table J5-12 maximum permitted values of starting current for direct-on-line LV motors (230/400 V)
			table J5-13 maximum permitted power ratings for LV direct-on-line-starting motors
		reactive-energy compensation (power-factor correction)
	protection of direct-current installations
		short-circuit currents
		characteristics of faults due to insulation failure, and of protective switchgear
			table J6-4 characteristics of protective switchgear according to type of d.c. system earthing
		choice of protective device
			table J6-5 choice of d.c. circuit breakers manufactured by Merlin Gerin
		protection of persons
	Appendix : Short-circuit characteristics of an alternator
Domestic and similar premises and special locaitons
	domestic and similar premises
		distribution-board components
		protection of persons
			table L1-9 recommended minimum number of lighting and power points in domestic premises
			table L1-11 c.s.a. of conductors and current rating of the protective devices in domestic installations (the c.s.a. of aluminium conductors are shown in brackets)
	bathrooms and showers
		classification of zones
		equipotential bonding
		requirements prescribed for each zone
	recommendations applicable to special installations and locations
Appendix - EMC
Document Text Contents
Page 1


This book, "Electrical Installation Guide according

to IEC International Standards", which is compiled

and printed in English by Schneider Electric,

facilitates utilization of the IEC 60364 series of

international standards concerned with safety,

guarding, control, performance and protection of

circuits, together with fundamentals and rules of

electrical installation design. Moreover,

the book contains topics of extreme importance

that cover wide fields of electric power systems

and their installations in different facilities. This

renders the book a useful reference to each

engineer and specialist in the field and an easy

guide to such international standards and their


SASO, in recognition of the guide's important and

comprehensive electric installation content, has

translated it into Arabic to enable researchers and

specialists to benefit from it in Arabic, if they


In its capacity as the body entrusted with issuing

and approving Saudi standards, SASO attaches

particular importance to verification of safety in

electrical installation in buildings. SASO is also

acting assiduously to complete work on the

national regulations of electrical installation

based upon IEC 60364 series of international

standards which are adopted as Saudi standards.

In view of the divergence of the items of such

standards and the many technical options

offered, issuing an application guide to these

standards is extremely useful. To this effect, the

Saudi national regulations of electrical

installation in buildings will be used.

The guide being introduced here, will be

an important reference for "the electrical

installation guide according to Saudi standards"

as part of the Saudi national regulations of

electrical installation in buildings.

Dr. Khaled Y. Al-Khalaf

Vice Chairman, Board of Directors

and Director General, SASO

Page 191


protection against electric shocks - G1

1. general

1.1 electric shock

when a current exceeding 30 mA
passes through a part of a human
body, the person concerned is in
serious danger if the current is not
interrupted in a very short time.

the protection of persons against
electric shock in LV installations must
be provided in conformity with
appropriate national standards and
statutory regulations, codes of
practice, official guides and circulars,
Relevant IEC standards include:
IEC 364, IEC 479-1, IEC 755,
IEC 1008, IEC 1009
and IEC 947-2 appendix B.

electric shock
An electric shock is the pathophysiological
effect of an electric current through the
human body.
Its passage affects essentially the circulatory
and respiratory functions and sometimes
results in serious burns. The degree of
danger for the victim is a function of the
magnitude of the current, the parts of the
body through which the current passes, and
the duration of current flow.
IEC Publication 479-1 defines four zones of
current-magnitude/time-duration, in each of
which the pathophysiological effects are
described (fig. G1). Any person coming into
contact with live metal risks an electric shock.

Curve C1 (of figure G1) shows that when a
current greater than 30 mA passes through a
part of a human being, the person concerned
is likely to be killed, unless the current is
interrupted in a relatively short time.
The point 500 ms/100 mA close to the curve
C1 corresponds to a probability of heart
fibrillation of the order of 0.14%.
The protection of persons against electric
shock in LV installations must be provided in
conformity with appropriate national
standards and statutory regulations, codes of
practice, official guides and circulars, etc.
Relevant IEC standards include: IEC 364,
IEC 479-1, IEC 755, IEC 1008, IEC 1009
and IEC 947-2 appendix B.

0,1 0,2 0,5 1 2 5 10 20 50 100 200 500 1000 2000 5000 10000

current passing through the body Is











21 3 4

A B C1 C2 C3

duration of current flow t

∂ imperceptible
∑ perceptible
∏ reversible effects:
π possibility of
C1: no heart fibrillation
C2: 5% probability
of heart fibrillation
C3: 50% probability
of heart fibrillation

fig. G1: curve C1 (of IEC 479-1) defines the current-magnitude/time-duration limits which
must not be exceeded.

1.2 direct and indirect contact

standards and regulations distinguish
two kinds of dangerous contact:
c direct contact,
c indirect contact,
and corresponding protective

direct contact
A direct contact refers to a person coming
into contact with a conductor which is live in
normal circumstances.

indirect contact
An indirect contact refers to a person coming
into contact with a conductive part which is
not normally alive, but has become alive
accidentally (due to insulation failure or some
other cause).

1 2 3 N





1 2 3 PE conductor


fig. G2: direct contact. fig. G3: indirect contact.

Is: touch current Id: insulation fault current

Similer Documents