IEC 60364-5-53:2001/AMD2:2015

Amendment 2 - Electrical installations of buildings - Part 5-53: Selection and erection of electrical equipment - Isolation, switching and control

Amendement 2 - Installations électriques des bâtiments - Partie 5-53: choix et mise en oeuvre des matériels électriques - Sectionnement, coupure et commande

General Information

• Status: Published
• Publication Date: 22-Sep-2015
• ICS: 29.130.01 - Switchgear and controlgear in general
• ICS: 91.140.50 - Electricity supply systems
• Technical Committee: TC 64 - Electrical installations and protection against electric shock
• Drafting Committee: MT 3 - TC 64/MT 3
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 21-Feb-2019

Relations

• Revised: IEC 60364-5-53:2019 - Low-voltage electrical installations - Part 5-53: Selection and erection of electrical equipment - Devices for protection for safety, isolation, switching, control and monitoring
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60364-5-53


®


Edition 3.0 2015-09



INTERNATIONAL



STANDARD



NORME
INTERNATIONALE
colour
inside
A MENDMENT 2
AM ENDEMENT 2

Electrical installations of buildings –
Part 5-53: Selection and erection of electrical equipment – Isolation, switching
and control

Installations électriques des bâtiments –
Partie 5-53: Choix et mise en oeuvre des matériels électriques – Sectionnement,
coupure et commande


IEC 60364-5-53:2001-08/AMD2:2015-09(en-fr)

---------------------- Page: 1 ----------------------
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IEC 60364-5-53



®



Edition 3.0 2015-09







INTERNATIONAL





STANDARD







NORME



INTERNATIONALE
colour

inside



A MENDMENT 2

AM ENDEMENT 2





Electrical installations of buildings –

Part 5-53: Selection and erection of electrical equipment – Isolation, switching

and control




Installations électriques des bâtiments –

Partie 5-53: Choix et mise en oeuvre des matériels électriques – Sectionnement,


coupure et commande















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 29.130; 91.140.50 ISBN 978-2-8322-2883-8



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---------------------- Page: 3 ----------------------
– 2 – IEC 60364-5-53:2001/AMD2:2015

 © IEC 2015


FOREWORD

This amendment has been prepared by IEC technical committee 64: Electrical installations

and protection against electric shock.


The text of this amendment is based on the following documents:


FDIS Report on voting

64/2031/FDIS 64/2072/RVD




Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its contents.
Users should therefore print this document using a colour printer.

_______


FOREWORD
Replace the existing text, including the text provided in Amendment 1:2002 that reads:
"This publication has been drafted, as close as possible, in accordance with the ISO/IEC

Directives, Part 3"
by the following new sentence:
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
Delete, from both IEC 60364-5-53:2001 and from Amendment 1:2002, the sentence that reads
"Annexes A, B, C and D are for information only."

530.2 Normative references
Add the following new references:
IEC 60038, IEC standard voltages
IEC 60364-5-54, Low-voltage electrical installations – Part 5-54: Selection and erection of
electrical equipment – Earthing arrangements and protective conductors

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IEC 60364-5-53:2001/AMD2:2015 – 3 –

© IEC 2015

IEC 61643-11:2011, Low-voltage surge protective devices – Part 11: Surge protective devices

connected to low-voltage power systems – Requirements and test methods


IEC 62305 (all parts), Protection against lightning

IEC 62305-1, Protection against lightning – Part 1: General principles


IEC 62305-2, Protection against lightning – Part 2: Risk management


IEC 62305-4, Protection against lightning – Part 4: Electrical and electronic systems within

structures



Replace the current reference to "IEC 61643-12" by the following:
IEC 61643-12:2008, Low-voltage surge protective devices – Part 12: Surge protective devices
connected to low-voltage power distribution systems – Selection and application principles
Replace the existing date "2001" for IEC 60364-4-41 by "2005"
Replace the existing date "2001" for IEC 60364-4-43 by "2008"
Replace the existing date "2001" for IEC 60364-4-44 by "2007"
Replace the existing date "1996" for IEC 61008-1 by "2010"

534 Devices for protection against electromagnetic and voltage disturbances
Replace the existing title and text of Clause 534, including the text provided in Amendment
1:2002, by the following new title and text:
534 Devices for protection against transient overvoltages
534.1 General
This clause contains provisions for the application of voltage limitation in order to obtain
insulation coordination in the cases described in IEC 60364-4-44, IEC 60664-1, IEC 62305-1,
IEC 62305-4 and IEC 61643-12.
This clause focuses mainly on the requirements for the selection and erection of SPDs for
protection against transient overvoltages where required by Clause 443 of IEC 60364-4-
44:2007, the IEC 62305 series, or as otherwise specified.
This clause does not take into account:

– surge protective components which may be incorporated in the appliances connected to
the installation;
– portable SPDs.
NOTE Further information can be found in IEC 61643-12.
This clause applies to a.c. power circuits. As far as it is applicable, the requirements of this
clause may be followed for d.c. power circuits.
534.2 Void
534.3 Terms and definitions
534.3.1
SPD assembly
one SPD or a set of SPDs, in both cases including all SPD disconnectors required by the SPD
manufacturer, providing the required overvoltage protection for a type of system earthing

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– 4 – IEC 60364-5-53:2001/AMD2:2015

 © IEC 2015

534.3.2

SPD disconnector

disconnector

device for disconnecting an SPD, or part of an SPD, from the power system

Note 1 to entry: This disconnecting device is not required to have isolating capability for safety purposes. It is to

prevent a persistent fault on the system and is used to give an indication of an SPD’s failure. Disconnectors can be

internal (built in) or external (required by the manufacturer). There may be more than one disconnector function, for
example an over-current protection function and a thermal protection function. These functions may be in separate
units.


[SOURCE: IEC 61643-11:2011, 3.1.28]

534.3.3

mode of protection of an SPD
intended current path, between terminals that contains protective components, e.g. line-to-
line, line-to-earth, line-to-neutral, neutral-to-earth
[SOURCE: IEC 61643-11:2011, 3.1.8]
534.3.4
follow current interrupt rating
I
fi
prospective short-circuit current that an SPD is able to interrupt without operation of a
disconnector
[SOURCE: IEC 61643-11:2011, 3.1.39]
534.3.5
short-circuit current rating
I
SCCR
maximum prospective short-circuit current from the power system for which the SPD, in
conjunction with the disconnector specified, is rated
[SOURCE: IEC 61643-11:2011, 3.1.27]
534.3.6
voltage protection level
U
P
maximum voltage to be expected at the SPD terminals due to an impulse stress with defined
voltage steepness and an impulse stress with a discharge current with given amplitude and
waveshape
Note 1 to entry: The voltage protection level is given by the manufacturer and may not be exceeded by:
– the measured limiting voltage determined for front-of-wave sparkover (if applicable) and the measured limiting
voltage determined from the residual voltage measurements at amplitudes corresponding to I and/or I
n imp

respectively for test classes II and/or I;
– the measured limiting voltage at the open circuit voltage of the combination wave generator (U ), determined
OC
for the combination wave for test class III.
[SOURCE: IEC 61643-11:2011, 3.1.14]
534.3.7
rated impulse voltage
U
W
impulse withstand voltage value assigned by the manufacturer to the equipment or to a part of
it, characterizing the specified withstand capability of its insulation against transient
overvoltages
[SOURCE: IEC 60664-1:2007, 3.9.2 MOD]

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IEC 60364-5-53:2001/AMD2:2015 – 5 –

© IEC 2015

534.3.8

maximum continuous operating voltage

U
C

maximum r.m.s. voltage, which may be continuously applied to the SPD's mode of protection


Note 1 to entry: The U value covered by this standard may exceed 1 000 V.
C

[SOURCE: IEC 61643-11:2011, 3.1.11]


534.3.9

nominal discharge current for class II test


I
n

crest value of the current through the SPD having a current waveshape of 8/20
[SOURCE: IEC 61643-11:2011, 3.1.9]
534.3.10
impulse discharge current for class I test
I
imp
crest value of a discharge current through the SPD with specified charge transfer Q and
specified energy W/R in the specified time
[SOURCE: IEC 61643-11:2011, 3.1.10]
534.3.11
two-port SPD
SPD having specific series impedance connected between separate input and output
connections
[SOURCE: IEC 61643-11:2011, 3.1.3]
534.4 Selection and erection of SPDs
534.4.1 SPD location and SPD test class
SPDs shall at least be installed as close as possible to the origin of the installation. For
protection against effects of lightning and against switching overvoltages, class II tested
SPDs shall be used.
Where the structure is equipped with an external lightning protection system or protection
against effects of direct lightning is otherwise specified, class I tested SPDs shall be used.
Where the structure is not equipped with an external lightning protection system and where
the occurrence of direct lightning strike to the overhead lines between the last pole and the
entrance of the installation is to be taken into consideration, class I tested SPDs at or near
the origin of the electrical installation may be also selected according to Annex B.

NOTE 1 The origin of the installation could be the location where the supply enters the building or the main
distribution board.
NOTE 2 Following the product standard, the marking of the product is as follows:
- for test class I: either “test class I” and/or “T1“ (T1 in a square);
- for test class II: either “test class II” and/or “T2“ (T2 in a square);
- for test class III: either “test class III, and/or “T3“(T3 in a square).
Additional class II tested or class III tested SPDs may be needed to sufficiently protect the
installation according to 534.4.4.2 and shall be located downstream in the fixed electrical
installation, for example in the sub-distribution boards or at the socket outlets. These SPDs
shall not be used without SPDs being installed at the origin of the installation and shall be
coordinated with SPDs located upstream (see 534.4.4.5).
If a class I tested SPD is not able to provide protection according to 534.4.4.2, it shall be
accompanied by a coordinated class II tested or class III tested SPD to ensure the required
voltage protection level.

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– 6 – IEC 60364-5-53:2001/AMD2:2015

 © IEC 2015

Additional class II tested SPDs or class III tested SPDs may be needed close to sensitive

equipment to sufficiently protect the equipment according to Table 534.1 and shall be

coordinated with SPDs located upstream.

NOTE 3 Such additional SPDs may be part of the fixed electrical installation or may be portable SPDs.


Additional SPDs may be necessary to provide transient overvoltage protection regarding

threats coming from other sources such as:

– switching overvoltages produced by current using equipment located within the

installation;


– overvoltages on other incoming services such as telephone lines, internet connections;

– overvoltages on other services feeding other structures such as secondary buildings,
external installations/lighting, power lines feeding external sensors;
in which case one should consider installing SPDs located as close as possible to the origin
of such threats. More information may be found in IEC 61643-12.

Figure 534.1 – Example of installation of class I, class II and class III tested SPDs
The presence of SPDs installed downstream of a distribution board (e.g. in a socket-outlet)
shall be permanently indicated (e.g. by a label) in this distribution board.
534.4.2 Transient overvoltage protection requirements
Protection against transient overvoltages may be provided:

– between live conductors and PE (common mode protection);
– between live conductors (differential mode protection)
NOTE 1 Connection type CT1 provides primarily common mode protection. If differential mode protection is also
necessary, this will in most cases require additional SPDs between live conductors.
NOTE 2 Connection type CT2 provides a combination of common mode protection and differential mode
protection.
Protection between live conductors and PE (including neutral to PE if there is a neutral
conductor) is compulsory.
Protection between line conductors and neutral (if there is a neutral conductor) is
recommended to ensure equipment protection.
Protection between line conductors (in the case of multiple phases) is optional.

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IEC 60364-5-53:2001/AMD2:2015 – 7 –

© IEC 2015

Some equipment may require both common mode protection (for impulse withstand) and

differential mode protection (for impulse immunity).


NOTE 3 For example, electronic class I equipment or class II equipment with FE-connection requires common
mode as well as differential mode protection to ensure overall protection against transient overvoltages due to

switching or from atmospheric origin.

534.4.3 Connection types


Connection type CT1 (e.g. 3+0 or 4+0-configuration): SPD assembly providing a mode of

protection between each live conductor (line and neutral conductors, if available) and PE or
between each line conductor and PEN.

Two examples of connection type CT1 for application in a three-phase system are

represented in Figure 534.2 and in Figure 534.3.
Connection type CT2 (e.g. 3+1-configuration): SPD assembly providing a mode of protection
between each line conductor and the neutral conductor, and between the neutral conductor
and PE.
An example of connection type CT2 for application in a three-phase system is represented in
Figure 534.4
L1 L2 L3 N
SS SS
SS SS
PP PP
PP PP
DD DD DD
DD
PE

Figure 534.2 – Connection type CT1 (4+0-configuration) for a three-phase system with
neutral
L1 L2 L3
S
SS SS SS
PP P
PP PP
DD DD D
DD

PEN

Figure 534.3 – Connection type CT1 (3+0-configuration) for a three-phase system

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– 8 – IEC 60364-5-53:2001/AMD2:2015

 © IEC 2015

L1 L2 L3 N



SS SS
SS

PP
PP
PP
DD
DD DD



SS

PP
DD


PE

Figure 534.4 – Connection type CT2 (e.g. 3+1-configuration)
for a three-phase system with neutral
When assembling SPDs, attention should be drawn to the selection of parameters for SPDs
connected between N and PE, depending on the connection type.
In TN-S or TN-C-S systems, the SPD between neutral and PE may be omitted if the distance
between the separation point of PE to N and the location of the installed SPDs is less than 0,5
m or if the separation point and the SPDs are located in the same distribution board.
If a line conductor is earthed, it is considered to be technically equivalent to a neutral
conductor for the application of this subclause. However correct choice of the SPD
parameters requires special considerations in such case.
534.4.4 Selection of SPDs
534.4.4.1  General
The selection of SPDs shall be based on the following parameters:
– voltage protection level (U ) and rated impulse voltage (U ) of equipment to be protected
p W
(see 534.4.4.2);
– continuous operating voltage (U ), i.e. supply system (TT, TN, IT) (see 534.4.4.3);
c
– nominal discharge current (I ) and impulse discharge current (I ) (see 534.4.4.4);
n imp
– SPD coordination (see 534.4.4.5);
– expected short-circuit current (see 534.4.4.6);
– follow current interrupting rating (see 534.4.4.7).
SPDs shall comply with the requirements of IEC 61643-11.
NOTE Additional information regarding selection and application is given in IEC 61643-12.
534.4.4.2 Selection of voltage protection level (U ) as a function of equipment rated
p
impulse voltage (U )
W
The voltage protection level U of SPDs shall be selected in accordance with required rated
p
impulse voltage according to overvoltage category II of Table 534.1. In order to provide
adequate protection of equipment, the voltage protection level between live conductors and
PE shall in no case exceed the required rated impulse voltage of the equipment according to
Table 534.1.
NOTE 1 Where only overvoltage category III or IV equipment is to be protected, reference is made to the required
rated impulse voltage of Table 443.2.
Where protection between line conductors and PE is provided by a series connection of SPD
protection modes (e.g. single mode SPDs, line–to-neutral + neutral-to-PE, according CT2),
this series connection shall fulfill the above voltage protection level requirement.

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IEC 60364-5-53:2001/AMD2:2015 – 9 –

© IEC 2015

Where such combined voltage protection level between line conductor and PE is not provided

in the data sheet of the manufacturer, it shall be calculated by addition of the voltage

protection levels given for the individual SPDs modes of protection, which are connected in

series.


It is recommended that the voltage protection level provided by SPDs does not exceed 80 %
of the required rated impulse voltage for equipment according to Table 534.1 and

corresponding to overvoltage category II, but shall in no case exceed the required rated

impulse voltage of the equipment.


This safety margin is not necessary where one of the following cases applies:


– where the equipment is connected directly to the SPD terminals;
– where a protection scheme according Figure 534.9 is already applied;
– where the voltage drop across the overcurrent protection in the SPD branch circuit is
already taken into account for the voltage protection level U ;
p
– where protection according to overvoltage category II is provided but only overvoltage
category III or IV equipment is installed at this location.
NOTE 2 IEC 61643-12 gives additional information about the rated impulse voltage of equipment and the given U
p
for the SPD.
Table 534.1 – Required rated impulse voltage of equipment
c
Required rated impulse voltage (U ) of
W
equipment for
Voltage line to
Nominal voltage Nominal
neutral from
of the supply voltage of the
Overvoltage category Overvoltage
a a nominal a.c. or
system supply system
II (equipment with category I
d.c. voltages
Three-phase Single -phase
up to and normal rated impulse (equipment with
systems systems
including voltage) reduced rated
impulse voltage)
V V V kV kV
 50 0,5 0,33
 100 0,8 0,5
120/240 150 1,5 0,8
230/400 300 2,5 1,5
277/480
400/690 600 4 2,5
1 000 1 000 6 4
b b
 1 500 d.c.
8 6

a
According to IEC 60038;
b
Recommended values based on Annex D of IEC 60664-2-1:2011;
c
The rated impulse voltage applies between live conductor and PE.

Additional SPDs between live conductors may be needed to avoid equipment malfunctions.
An appropriate voltage protection level needs to be evaluated based on equipment immunity
and availability requirements (see IEC 61643-12).
Where the required voltage protection level cannot be met with a single SPD assembly,
additional coordinated SPDs shall be applied to ensure the required voltage protection level.
534.4.4.3 Selection of SPDs with regard to continuous operating voltage (U )
c
In a.c., the maximum continuous operating voltage U of SPDs shall be equal to or higher than
c
required in Table 534.2.

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– 10 – IEC 60364-5-53:2001/AMD2:2015

 © IEC 2015

Table 534.2 – U of the SPD dependent on supply system configuration
c


SPD connected System configuration of distribution network

between
TN system TT system IT system

(as applicable)

1,1 U 1,1 U 1,1 U

Line conductor

√3 √3 √3
and neutral conductor

or (0,64 × U) or (0,64 × U) or (0,64 × U)

1,1 U 1,1 U


Line conductor and PE conductor √3 √3 1,1 × U

or (0,64 × U) or (0,64 × U)

1,1 U

Line conductor and PEN conductor √3 N/A N/A
or (0,64 × U)
1,1 U

U U
  a  a
Neutral conductor and PE conductor √3

√3 √3
or (0,64 × U)
Line conductors 1,1 U 1,1 U 1,1 U
NOTE 1 N/A: not applicable.
NOTE 2 U is the line-to-line voltage of the low-voltage system.

a
These values are related to worst-case fault conditions, therefore the tolerance of 10 % is not taken into
account.

534.4.4.4 Selection of SPDs with regard to nominal discharge current (I ) and impulse
n
discharge current (I )
imp
At or near the origin of the installation, SPDs shall comply with one of the following cases, as
applicable:
– where the building is protected against direct lightning strike, SPDs at the origin of the
installation shall be selected according to 534.4.4.4.2 and Table 534.4;
– in other cases, SPDs shall be selected according to 534.4.4.4.1.
Further SPDs installed downstream of the SPDs at or near the origin of the installation shall
also comply with the coordination requirements in 534.4.4.5.
Overvoltages due to switching can be longer in duration and can contain more energy than
the transient overvoltages of atmospheric origin. This has to be considered for the selection of
SPDs with regard to nominal discharge current and impulse discharge current
534.4.4.4.1 Class II tested SPDs

Where class II tested SPD are required at or near the origin of installation, their nominal
discharge current shall be not less than that given in Table 534.3.
Table 534.3 – Nominal discharge current (I ) in kA depending on supply system and
n
connection type
Connection Supply system
Single-phase Three-phase
CT1 CT2 CT1 CT2
5 5
L − N
L − PE 5 5
N – PE 5 10 5 20

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IEC 60364-5-53:2001/AMD2:2015 – 11 –

© IEC 2015

534.4.4.4.2 Class I tested SPDs

Where class I tested SPDs are required at or near the origin of the installation, one of the

following cases applies:


a) Where no risk analysis according to IEC 62305-2 has been carried out, the impulse

discharge current (I ) shall be not less than as given in Table 534.4:
imp

Table 534.4 – Selection of impulse discharge current (I ) where the building is

imp

protected against direct lightning strike

I in kA

imp

Supply system
Connection
Single phase Three phase
CT1 CT2 CT1 CT2
L − N 12,5 12,5
12,5 12,5
L − PE
12,5 25 12,5 50
N − PE
NOTE This table refers to lightning protection levels (LPL) III and IV.

b) Where the risk analysis according to IEC 62305-2 has been carried out, the impulse
discharge current (I ) shall be determined according to the IEC 62305 series.
imp
534.4.4.5 Coordination of two or several SPDs
Coordination of SPDs in the installation needs to be ensured. The manufacturer's instructions
on how to achieve coordination between SPDs shall be followed with reference IEC 61643-12.
534.4.4.6 Selection of SPDs with regard to the short-circuit current rating I
SCCR
In general, the short-circuit current rating I of the SPD, as stated by the manufacturer,
SCCR
shall be not lower than the maximum prospective short-circuit current at the connection points
of the SPD assembly. See Figure 534.5
This requirement does not apply to SPDs connected between neutral conductor and PE in TN
or TT systems, for which this is already covered by the product standard IEC 61643-11.
For SPDs connected between the neutral conductor and PE in IT systems, the short-circuit
current rating I of the SPD shall not be lower than the maxim
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