IEC 60947-1:2007

IEC 60947-1 ®
Edition 5.1 2011-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 1: General rules
Appareillage à basse tension –
Partie 1: Règles générales
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IEC 60947-1 ®
Edition 5.1 2011-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –
Part 1: General rules
Appareillage à basse tension –
Partie 1: Règles générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX CU
ICS 29.130.20 ISBN 978-2-88912-340-7

– 2 – 60947-1 © IEC:2007+A1:2010

CONTENTS
FOREWORD . 7

General . 9
1.1 Scope and object. 9

1.2 Normative references . 10

2 Definitions . 14

2.1 General terms . 18

2.2 Switching devices . 21
2.3 Parts of switching devices . 24
2.4 Operation of switching devices . 29
2.5 Characteristic quantities . 33
2.6 Tests . 42
2.7 Ports . 42
3 Classification . 43
4 Characteristics . 44
4.1 General . 45
4.2 Type of equipment . 45
4.3 Rated and limiting values for the main circuit . 45
4.4 Utilization category . 51
4.5 Control circuits . 51
4.6 Auxiliary circuits . 52
4.7 Relays and releases . 53
4.8 Co-ordination with short-circuit protective devices (SCPD) . 53
4.9 Switching overvoltages . 53
5 Product information . 53
5.1 Nature of information . 53
5.2 Marking . 54
5.3 Instructions for installation, operation and maintenance . 55
6 Normal service, mounting and transport conditions . 56
6.1 Normal service conditions . 56
6.2 Conditions during transport and storage . 58
6.3 Mounting . 58

7 Constructional and performance requirements . 58
7.1 Constructioynal requirements . 58
7.2 Performance requirements . 66
7.3 Electromagnetic compatibility (EMC) . 74
8 Tests . 75
8.1 Kinds of test . 75
8.2 Compliance with constructional requirements . 77
8.3 Performance . 83
8.4 Tests for EMC . 104

60947-1 © IEC:2007+A1:2010 − 3 −

Annex A (informative) Examples of utilization categories for low-voltage switchgear

and controlgear . 145

Annex B (informative) Suitability of the equipment when conditions for operation in

service differ from the normal conditions . 148

Annex C (normative) Degrees of protection of enclosed equipment . 149

Annex D (informative) Examples of terminals clamping units and relationship

between clamping unit and connecting device . 156

Annex E (informative) Description of a method for adjusting the load circuit . 171

Annex F (informative) Determination of short-circuit power-factor or time-constant . 173

Annex G (informative) Measurement of creepage distances and clearances . 175
Annex H (informative) Correlation between the nominal voltage of the supply system
and the rated impulse withstand voltage of equipment . 181
Annex J (informative) Items subject to agreement between manufacturer and user . 183
Annex K Vacant . 184
Annex L (normative) Terminal marking and distinctive number . 185
Annex M (normative) Flammability test . 196
Annex N (normative) Requirements and tests for equipment with protective separation . 203
Annex O (informative) Environmental aspects . 208
Annex P (informative) Terminal lugs for low voltage switchgear and controlgear
connected to copper conductors . 217
Annex Q (normative) Special tests – Damp heat, salt mist, vibration and shock . 218
Annex R (informative) Application of the metal foil for dielectric testing on accessible
parts during operation or adjustment . 224
Annex S (normative) Digital inputs and outputs . 230
Annex T (normative) Extended functions within electronic overload relays . 244
Annex U (informative) Examples of control circuit configurations . 249

Bibliography . 252

Table 1 – Standard cross-sections of round copper conductors and approximate
relationship between mm and AWG/kcmil sizes (see 7.1.8.2) . 107
Table 2 – Temperature-rise limits of terminals (see 7.2.2.1 and 8.3.3.3.4) . 108
Table 3 – Temperature-rise limits of accessible parts (see 7.2.2.2 and 8.3.3.3.4) . 108
Table 4 – Tightening torques for the verification of the mechanical strength of screw-

type terminals (see 8.3.2.1, 8.2.6 and 8.2.6.2) . 109
Table 5 – Test values for flexion and pull-out tests for round copper conductors (see
8.2.4.4.1) . 110
Table 6 – Test values for pull-out test for flat copper conductors (see 8.2.4.4.2) . 111
Table 7 – Maximum conductor cross-sections and corresponding gauges (see
8.2.4.5.1) . 111
Table 7a – Relationship between conductor cross-section and diameter . 112
Table 8 – Tolerances on test quantities (see 8.3.4.3, item a)) . 113
Table 9 – Test copper conductors for test currents up to 400 A inclusive (see 8.3.3.3.4) . 113
Table 10 – Test copper conductors for test currents above 400 A and up to 800 A
inclusive (see 8.3.3.3.4) . 114
Table 11 – Test copper bars for test currents above 400 A and up to 3 150 A inclusive
(see 8.3.3.3.4) . 114

– 4 – 60947-1 © IEC:2007+A1:2010

Table 12 – Impulse withstand test voltages . 115

Table 12A – Dielectric test voltage corresponding to the rated insulation voltage . 115

Table 13 – Minimum clearances in air . 116

Table 14 – Test voltages across the open contacts of equipment suitable for isolation . 116

Table 15 – Minimum creepage distances . 117

Table 16 – Values of power-factors and time-constants corresponding to test currents,

and ratio n between peak and r.m.s. values of current (see 8.3.4.3, item a)) . 119

Table 17 – Actuator test force (see 8.2.5.2.1) . 119

Table 18 – Vacant . 119

Table 19 – Vacant . 119
Table 20 – Test values for conduit pull-out test (see 8.2.7.1) . 119
Table 21 – Test values for conduit bending test (see 8.2.7.2) . 120
Table 22 – Test values for conduit torque test (see 8.2.7.1 and 8.2.7.3) . 120
Table 23 – Tests for EMC – Immunity (see 8.4.1.2). 121
Table 24 – Acceptance criteria when EM disturbances are present . 123
Table H.1 – Correspondence between the nominal voltage of the supply system and
the equipment rated impulse withstand voltage, in case of overvoltage protection by
surge-arresters according to IEC 60099-1 . 182
Table M.1 – HWI and AI characteristics for materials necessary to retain current
carrying parts in position . 202
Table M.2 – HWI and AI characteristics for materials other than those covered by
Table M.1 . 202
Table P.1 – Examples of terminal lugs for low voltage switchgear and controlgear
connected to copper conductors . 217
Table Q.1 – Test sequences . 220
Table S.1 – Rated values and operating ranges of incoming power supply . 231
Table S.2 – Standard operating ranges for digital inputs (current sinking) . 234
Table S.3 – Rated values and operating ranges for current sourcing digital a.c. outputs . 235
Table S.4 – Rated values and operating ranges (d.c.) for current-sourcing digital d.c.
outputs . 237
Table S.5 – Overload and short-circuit tests for digital outputs . 240
Table T.1 – Operating time of ground/earth fault electronic overload relays . 245

Figure 1 – Test equipment for flexion test (see 8.2.4.3 and Table 5) . 124
Figure 2 – Gauges of form A and form B (see 8.2.4.5.2 and Table 7) . 124
Figure 3 – Diagram of the test circuit for the verification of making and breaking
capacities of a single-pole equipment on single-phase a.c. or on d.c. (see 8.3.3.5.2) . 125
Figure 4 – Diagram of the test circuit for the verification of making and breaking
capacities of a two-pole equipment on single-phase a.c. or on d.c. (see 8.3.3.5.2) . 126
Figure 5 – Diagram of the test circuit for the verification of making and breaking
capacities of a three-pole equipment (see 8.3.3.5.2) . 127
Figure 6 – Diagram of the test circuit for the verification of making and breaking
capacities of a four-pole equipment (see 8.3.3.5.2) . 128
Figure 7 – Schematic illustration of the recovery voltage across contacts of the first
phase to clear under ideal conditions (see 8.3.3.5.2, item e)). 129
Figure 8a – Diagram of a load circuit adjustment method: load star-point earthed . 130
Figure 8b – Diagram of a load circuit adjustment method: supply star-point earthed . 131

60947-1 © IEC:2007+A1:2010 − 5 −

Figure 9 – Diagram of the test circuit for the verification of short-circuit making and

breaking capacities of a single-pole equipment on single-phase a.c. or on d.c. (see

8.3.4.1.2) . 132

Figure 10 – Diagram of the test circuit for the verification of short-circuit making and

breaking capacities of a two-pole equipment on single-phase a.c. or on d.c. (see

8.3.4.1.2) . 133

Figure 11 – Diagram of the test circuit for the verification of short-circuit making and

breaking capacities of a three-pole equipment (see 8.3.4.1.2). 134

Figure 12 – Diagram of the test circuit for the verification of short-circuit making and
breaking capacities of a four-pole equipment (see 8.3.4.1.2) . 135

Figure 13 – Example of short-circuit making and breaking test record in the case of a
single-pole equipment on single-phase a.c. (see 8.3.4.1.8) . 136
Figure 14 – Verification of short-circuit making and breaking capacities on d.c. (see
8.3.4.1.8) . 137
Figure 15 – Determination of the prospective breaking current when the first calibration
of the test circuit has been made at a current lower than the rated breaking capacity
(see 8.3.4.1.8, item b)) . 138
Figure 16 – Actuator test force (see 8.2.5.2.1 and Table 17) . 139
Figure 17 – Examples of ports . 140
Figure 18 – Test set-up for the verification of immunity to electrostatic discharges . 140
Figure 19 – Test set-up for the verification of immunity to radiated radio-frequency
electromagnetic fields . 141
Figure 20 – Test set-up for the verification of immunity to electrical fast
transients/bursts . 142
Figure 21 – Test set-up for the verification of immunity to conducted disturbances
induced by r.f. fields on power lines . 143
Figure 22 – Example of test set-up for the verification of immunity to conducted
disturbances induced by r.f. fields on signal lines when CDN´s are not suitable . 143
Figure 23 – Test set-up for the verification of immunity to power frequency magnetic
fields. 144
Figure C.1 – IP Codes . 153
Figure D.1 − Screw terminals . 156
Figure D.2 – Pillar terminals. 157
Figure D.3 − Stud terminals . 158
Figure D.4 – Saddle terminals . 159

Figure D.5 – Lug terminals . 160
Figure D.6 – Mantle terminals . 161
Figure D.7 – Screwless-type terminals . 162
Figure D.1 − Screw clamping units . 164
Figure D.2 – Pillar clampings units . 165
Figure D.3 − Stud clamping units . 166
Figure D.4 – Saddle terminals . 167
Figure D.5 – Lug clamping units . 168
Figure D.6 – Mantle clamping units . 169
Figure D.7 – Screwless-type clamping units . 170
Figure D.8 – Clamping unit in a connecting device . 163
Figure E.1 – Determination of the actual value of the factor γ . 172

– 6 – 60947-1 © IEC:2007+A1:2010

Figure G.1 – Measurement of ribs . 176

Figure G.2 – Creepage distance across the fixed and moving insulation of contact

carriers . 176

Figure M.1 – Test fixture for hot wire ignition test . 199

Figure M.2 – Circuit for arc ignition test . 200

Figure N.1 – Example of application with component connected between separated

circuits . 207

Figure O.1 − Conceptual relationship between provisions in product standards and the
environmental impacts associated with the product during its life cycle . 213

Figure P.1 – Dimensions . 217
Figure R.1 – Operating mechanism outside the enclosure . 226
Figure R.2 – Operating space for push-button actuation . 227
Figure R.3 – Examples of finger protected location for hazardous-live-parts in push-
button vicinity (approximately 25 mm) . 228
Figure R.4 – Operating space for actuation by rotary means . 229
Figure S.1 – I/O parameters . 232
Figure S.2 – U-I operation regions of current-sinking inputs . 233
Figure S.3 – Temporary overload waveform for digital a.c. outputs . 235
Figure S.4 – Temporary overload waveform for digital d.c. outputs . 238
Figure T.1 – Test circuit for the verification of the operating characteristic
of a ground/earth fault current sensing electronic relay . 248
Figure U.1 – Diagrammatic representation of an ECD . 249
Figure U.2 – Single supply and control input . 250
Figure U.3 – Separate supply and control inputs . 250
Figure U.4 – Equipment with an internal control supply and control input only . 251
Figure U.5 – Equipment with several external control supplies . 251
Figure U.6 – Equipment with bus interface . 251

60947-1 © IEC:2007+A1:2010 − 7 −

INTERNATIONAL ELECTROTECHNICAL COMMISSION

_____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 1: General rules
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-
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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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.

This consolidated version of IEC 60947-1 consists of the fifth edition (2007) [documents
17B/1550/FDIS and 17B/1563/RVD] and its amendment 1 (2010) [documents
17B/1710/FDIS and 17B/1721/RVD]. It bears the edition number 5.1.
The technical content is therefore identical to the base edition and its amendment and
has been prepared for user convenience. A vertical line in the margin shows where the
base publication has been modified by amendment 1. Additions and deletions are
displayed in red, with deletions being struck through.

– 8 – 60947-1 © IEC:2007+A1:2010

International Standard IEC 60947-1 has been prepared by subcommittee 17B: Low-voltage

switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all the parts in the IEC 60947 series, under the general title Low-voltage switchgear

and controlgear can be found on the IEC website.

The committee has decided that the contents of the base publication and its amendments will

remain unchanged until the stability 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.
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 publication using a colour printer.

60947-1 © IEC:2007+A1:2010 − 9 −

LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 1: General rules
1 General
The purpose of this standard is to harmonize as far as practicable all rules and requirements
of a general nature applicable to low-voltage switchgear and controlgear in order to obtain
uniformity of requirements and tests throughout the corresponding range of equipment and to

avoid the need for testing to different standards.
All those parts of the various equipment standards which can be considered as general have
therefore been gathered in this standard together with specific subjects of wide interest and
application, e.g. temperature-rise, dielectric properties, etc.
For each type of low-voltage switchgear and controlgear, only two main documents are
necessary to determine all requirements and tests:
1) this basic standard, referred to as "Part 1" in the specific standards covering the various
types of low-voltage switchgear and controlgear;
2) the relevant equipment standard hereinafter referred to as the "relevant product standard"
or "product standard".
For a general rule to apply to a specific product standard, it shall be explicitly referred to by
the latter, by quoting the relevant clause or subclause number of this standard followed by
"IEC 60947-1" e.g. "7.2.3 of IEC 60947-1".
A specific product standard may not require, and hence may omit, a general rule (as being not
applicable), or it may add to it (if deemed inadequate in the particular case), but it may not
deviate from it, unless there is a substantial technical justification.
NOTE The product standards due to be part of the series of IEC standards covering low-voltage switchgear and
controlgear are:
IEC 60947-2: Part 2: Circuit-breakers
IEC 60947-3: Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units
IEC 60947-4: Part 4: Contactors and motor-starters
IEC 60947-5: Part 5: Control-circuit devices and switching elements

IEC 60947-6: Part 6: Multiple function equipment
IEC 60947-7: Part 7: Ancillary equipment
IEC 60947-8: Part 8: Control units for built-in thermal protection (PTC) for rotating electrical machines.
1.1 Scope and object
This standard applies, when required by the relevant product standard, to switchgear and
controlgear hereinafter referred to as "equipment" and intended to be connected to circuits,
the rated voltage of which does not exceed 1 000 V a.c. or 1 500 V d.c.
It does not apply to low-voltage switchgear and controlgear assemblies which are dealt with in
IEC 60439.
NOTE In certain clauses or subclauses of this standard, the equipment covered by this standard is also referred
to as "device", to be consistent with the text of such clauses or subclauses.

– 10 – 60947-1 © IEC:2007+A1:2010

The object of this standard is to state those general rules and requirements which are

common to low-voltage equipment as defined in 1.1, including for example:

– definitions;
– characteristics;
– information supplied with the equipment;

– normal service, mounting and transport conditions;

– constructional and performance requirements;

– verification of characteristics and performance.

Digital inputs and/or digital outputs contained in switchgear and controlgear, and intended to
be compatible with programmable controllers (PLCs) are covered by Annex S.
1.2 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 60050(151):2001, International Electrotechnical Vocabulary (IEV) – Chapter 151:
Electrical and magnetic devices
IEC 60050(441):1984, International Electrotechnical Vocabulary (IEV) – Chapter 441:
Switchgear, controlgear and fuses
Amendment 1 (2000)
IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) – Chapter 604:
Generation, transmission and distribution of electricity – Operation
Amendment 1 (1998)
IEC 60050(826):2004, International Electrotechnical Vocabulary (IEV) – Chapter 826:
Electrical installations
IEC 60060, High-voltage test techniques
IEC 60068-1:1988, Environmental testing − Part 1: General and guidance
Amendment 1 (1992)
IEC 60068-2-1:1990, Environmental testing − Part 2-1: Tests − Tests A: Cold

Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-2:1974, Environmental testing − Part 2-2: Tests − Tests B: Dry heat
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-6:1995, Environmental testing − Part 2-6: Tests − Test Fc: Vibration (sinusoidal)
IEC 60068-2-27:1987, Environmental testing − Part 2-27: Tests − Test Ea and guidance:
Shock
IEC 60068-2-30:2005, Environmental testing − Part 2-30: Tests − Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
60947-1 © IEC:2007+A1:2010 − 11 −

IEC 60068-2-52:1996, Environmental testing − Part 2-52: Tests − Test Kb: Salt mist, cyclic

(sodium chloride solution)
IEC 60068-2-78:2001, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat,

steady state
IEC 60071-1:1993, Insulation co-ordination – Part 1: Definitions, principles and rules

IEC 60073:2002, Basic and safety principles for man-machine interface, marking and

identification – Coding principles for indicators and actuators

IEC 60085:2004, Electrical insulation – Thermal classification
IEC 60112:2003, Method for the determination of the proof and the comparative tracking
indices of solid insulating materials
IEC 60216, Guide for the determination of thermal endurance properties of electrical
insulating materials
IEC 60228:2004, Conductors of insulated cables
IEC 60269-1:1998, Low-voltage fuses – Part 1: General requirements
Amendment 1 (2005)
IEC 60269-2:1986, Low-voltage fuses – Part 2: Supplementary requirements for fuses for use
by authorized persons (fuses mainly for industrial application)
Amendment 1 (1995)
Amendment 2 (2001)
IEC 60344:1980, Guide to the calculation of resistance of plain and coated copper conductors
of low-frequency cables and wires
Amendment 1 (1985)
IEC 60364-4-44:2001, Electrical installations of buildings – Part 4-44: Protection for safety –
Protection against voltage disturbances and electromagnetic disturbances
Amendment 1 (2003)
IEC 60417-DB:2002 , Graphical symbols for use on equipment
IEC 60439-1:1999, Low-voltage switchgear and controlgear assemblies – Part 1: Type-tested

and partially type-tested assemblies
Amendment 1 (2004)
IEC 60445:1999, 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 of an alphanumeric system
IEC 60447:2004, Basic and safety principles for man-machine interface, marking and
identification – Actuating principles
IEC 60529:1989, Degrees of protection provided by enclosures (IP code)
Amendment 1 (1999)
___________
“DB” refers to the IEC on-line database.

– 12 – 60947-1 © IEC:2007+A1:2010

IEC 60617-DB:2001 , Graphical symbols for diagrams

IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:

Principles, requirements and tests – Basic safety publication

Amendment 1 (2000)
Amendment 2 (2002)
IEC 60664-3:2003, Insulation coordination for equipment within low-voltage systems – Part 3:

Use of coating, potting or moulding for protection against pollution

IEC 60664-5:2007, Insulation coordination for equipment within low-voltage systems – Part 5:

Comprehensive method for determining clearances and creepage distances equal to or less
than 2 mm
IEC 60695-2-2:1991, Fire hazard testing – Part 2: Test methods – Section 2: Needle-flame test
Amendment 1 (1994)
IEC 60695-2-10:2000, Fire hazard testing – Part 2-10: Glowing/hot-wire based test methods –
Glow-wire apparatus and common test procedure
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products
IEC 60695-2-12, Fire hazard testing – Part 2-12: Glowing/hot-wire based test methods –
Glow-wire flammability test method for materials
IEC 60695-11-10:1999, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and
vertical flame test methods
Amendment 1 (2003)
IEC 60947-5-1:2003, Low-voltage switchgear and controlgear – Part 5-1: Control circuit
devices and switching elements – Electromechanical control circuit devices
IEC 60947-8:2003, Low-voltage switchgear and controlgear – Part 8: Control units for built-in
thermal protection (PTC) for rotating electrical machines
Amendment 1 (2006)
IEC 60981:2004, Extra heavy-duty electrical rigid steel conduits
IEC 60999-1:1999, Connecting devices – Electrical copper conductors – Safety requirements

for screw-type and screwless-type clamping units – Part 1: General requirements and
particular requirements for clamping units for conductors from 0,2 mm² up to 35 mm²
(included)
IEC 60999-2:2003, Connecting devices – Electrical copper conductors – Safety requirements
for screw-type and screwless-type clamping units – Part 2: Particular requirements for
2 2
clamping units for conductors above 35 mm up to 300 mm (included)
IEC 61000-3-2:2005, Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for
harmonic current emissions (equipment input current ≤ 16 A per phase)
IEC 61000-3-3:1994, Electromagnetic compatibility (EMC) – Part 3: Limits – Section 3:
Limitation of voltage fluctuations and flicker in low-voltage supply systems for equipment with
rated current ≤ 16 A
Amendment 1 (2001)
Amendment 2 (2005)
60947-1 © IEC:2007+A1:2010 − 13 −

IEC 61000-4-2:1995, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement

techniques – Section 2: Electrostatic discharge immunity test – Basic EMC publication

Amendment 1 (1998)
Amendment 2 (2000)
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measure-

ment techniques – Radiated, radio-frequency, electromagnetic field immunity test

IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and meas
...

IEC 60947-1 ®
Edition 5.2 2014-09
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Low-voltage switchgear and controlgear –
Part 1: General rules
Appareillage à basse tension –
Partie 1: Règles générales
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IEC 60947-1 ®
Edition 5.2 2014-09
CONSOLIDATED
VERSION
VERSION
CONSOLIDÉE
colour
inside
Low-voltage switchgear and controlgear –

Part 1: General rules
Appareillage à basse tension –

Partie 1: Règles générales
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-1823-5

IEC 60947-1 ®
Edition 5.2 2014-09
REDLINE VERSION
VERSION REDLINE
colour
inside
Low-voltage switchgear and controlgear –
Part 1: General rules
Appareillage à basse tension –
Partie 1: Règles générales
– 2 – IEC 60947-1:2007
+AMD1:2010+AMD2:2014 CSV © IEC 2014

CONTENTS
FOREWORD . 7

1 General . 9

1.1 Scope and object . 9

1.2 Normative references . 10

2 Definitions . 14

2.1 General terms. 19

2.2 Switching devices . 22
2.3 Parts of switching devices . 25
2.4 Operation of switching devices . 30
2.5 Characteristic quantities . 34
2.6 Tests . 43
2.7 Ports . 43
3 Classification . 44
4 Characteristics . 45
4.1 General . 45
4.2 Type of equipment . 46
4.3 Rated and limiting values for the main circuit . 46
4.4 Utilization category . 52
4.5 Control circuits . 52
4.6 Auxiliary circuits . 53
4.7 Relays and releases . 53
4.8 Co-ordination with short-circuit protective devices (SCPD) . 53
4.9 Switching overvoltages . 53
5 Product information. 54
5.1 Nature of information . 54
5.2 Marking . 55
5.3 Instructions for installation, operation and maintenance . 56
6 Normal service, mounting and transport conditions . 56
6.1 Normal service conditions . 56
6.2 Conditions during transport and storage . 58
6.3 Mounting . 58

7 Constructional and performance requirements . 58
7.1 Constructional requirements . 58
7.2 Performance requirements . 67
7.3 Electromagnetic compatibility (EMC) . 74
8 Tests . 76
8.1 Kinds of test . 76
8.2 Compliance with constructional requirements . 77
8.3 Performance . 84
8.4 Tests for EMC . 104

+AMD1:2010+AMD2:2014 CSV © IEC 2014

Annex A (informative) Examples Harmonization of utilization categories for low-voltage

switchgear and controlgear. 145

Annex B (informative) Suitability of the equipment when conditions for operation in

service differ from the normal conditions . 150

Annex C (normative) Degrees of protection of enclosed equipment . 151

Annex D (informative) Examples of terminals clamping units and relationship between

clamping unit and connecting device . 158

Annex E (informative) Description of a method for adjusting the load circuit . 168

Annex F (informative) Determination of short-circuit power-factor or time-constant . 170

Annex G (informative) Measurement of creepage distances and clearances . 172
Annex H (informative) Correlation between the nominal voltage of the supply system
and the rated impulse withstand voltage of equipment . 178
Annex J (informative) Items subject to agreement between manufacturer and user . 180
Annex K Vacant (normative) Procedure to determine reliability data for
electromechanical devices used in functional safety applications . 181
Annex L (normative) Terminal marking and distinctive number . 191
Annex M (normative) Flammability test . 202
Annex N (normative) Requirements and tests for equipment with protective separation . 207
Annex O (informative) Environmentally-conscious aspects design . 212
Annex P (informative) Terminal lugs for low voltage switchgear and controlgear
connected to copper conductors . 229
Annex Q (normative) Special tests – Damp heat, salt mist, vibration and shock . 230
Annex R (informative normative) Application of the metal foil for dielectric testing on
accessible parts during operation or adjustment . 236
Annex S (normative) Digital inputs and outputs . 242
Annex T (normative) Extended functions within electronic overload relays . 256
Annex U (informative) Examples of control circuit configurations . 261
Annex V (informative) Power management with switchgear and controlgear
for electrical energy efficiency . 264
Annex W (normative) Procedure to establish material declaration . 267
Bibliography . 269

Table 1 – Standard Nominal cross-sections of round copper conductors and

approximate relationship between mm and AWG/kcmil sizes (see 7.1.8.2) . 108
Table 2 – Temperature-rise limits of terminals (see 7.2.2.1 and 8.3.3.3.4). 108
Table 3 – Temperature-rise limits of accessible parts (see 7.2.2.2 and 8.3.3.3.4) . 109
Table 4 – Tightening torques for the verification of the mechanical strength of screw-
type terminals (see 8.2.4.2 and 8.3.2.1 , 8.2.6 and 8.2.6.2) . 110
Table 5 – Test values for flexion and pull-out tests for round copper conductors (see
8.2.4.4.1) . 111
Table 6 – Test values for pull-out test for flat copper conductors (see 8.2.4.4.2) . 111
Table 7 – Maximum conductor cross-sections and corresponding gauges (see
8.2.4.5.1) . 112
Table 7a – Relationship between conductor cross-section and diameter . 113
Table 8 – Tolerances on test quantities (see 8.3.4.3, item a)) . 114
Table 9 – Test copper conductors for test currents up to 400 A inclusive (see 8.3.3.3.4) . 114

– 4 – IEC 60947-1:2007
+AMD1:2010+AMD2:2014 CSV © IEC 2014

Table 10 – Test copper conductors for test currents above 400 A and up to 800 A

inclusive (see 8.3.3.3.4) . 115

Table 11 – Test copper bars for test currents above 400 A and up to 3 150 A inclusive

(see 8.3.3.3.4) . 115

Table 12 – Impulse withstand test voltages . 116

Table 12A – Dielectric test voltage corresponding to the rated insulation voltage . 116

Table 13 – Minimum clearances in air. 117

Table 14 – Test voltages across the open contacts of equipment suitable for isolation . 117

Table 15 – Minimum creepage distances . 118

Table 16 – Values of power-factors and time-constants corresponding to test currents,
and ratio n between peak and r.m.s. values of current (see 8.3.4.3, item a)) . 120
Table 17 – Actuator test force (see 8.2.5.2.1) . 120
Table 18 – Vacant . 120
Table 19 – Vacant . 120
Table 20 – Test values for conduit pull-out test (see 8.2.7.1) . 120
Table 21 – Test values for conduit bending test (see 8.2.7.2) . 121
Table 22 – Test values for conduit torque test (see 8.2.7.1 and 8.2.7.3) . 121
Table 23 – Tests for EMC – Immunity (see 8.4.1.2) . 122
Table 24 – Acceptance criteria when EM disturbances are present . 123
Table A.1 – Utilization categories used in IEC 60947 series . 147
Table H.1 – Correspondence between the nominal voltage of the supply system and the
equipment rated impulse withstand voltage, in case of overvoltage protection by surge-
arresters according to IEC 60099-1 . 179
Table K.1 – Failure modes of devices . 183
Table K.2 – Example of 15 sorted ascending times to failure of contractors . 188
Table K.3 – Example median rank calculation . 189
Table M.1 – HWI and AI characteristics for materials necessary to retain current
carrying parts in position . 206
Table M.2 – HWI and AI characteristics for materials other than those covered by
Table M.1 . 206
Table P.1 – Examples of terminal lugs for low voltage switchgear and controlgear
connected to copper conductors . 229
Table Q.1 – Test sequences . 232

Table S.1 – Rated values and operating ranges of incoming power supply . 243
Table S.2 – Standard operating ranges for digital inputs (current sinking) . 246
Table S.3 – Rated values and operating ranges for current sourcing digital a.c. outputs . 247
Table S.4 – Rated values and operating ranges (d.c.) for current-sourcing digital d.c.
outputs. 249
Table S.5 – Overload and short-circuit tests for digital outputs . 252
Table T.1 – Operating time of ground/earth fault electronic overload relays . 257

Figure 1 – Test equipment for flexion test (see 8.2.4.3 and Table 5) . 124
Figure 2 – Gauges of form A and form B (see 8.2.4.5.2 and Table 7) . 124
Figure 3 – Diagram of the test circuit for the verification of making and breaking
capacities of a single-pole equipment on single-phase a.c. or on d.c. (see 8.3.3.5.2) . 125
Figure 4 – Diagram of the test circuit for the verification of making and breaking
capacities of a two-pole equipment on single-phase a.c. or on d.c. (see 8.3.3.5.2) . 126

+AMD1:2010+AMD2:2014 CSV © IEC 2014

Figure 5 – Diagram of the test circuit for the verification of making and breaking

capacities of a three-pole equipment (see 8.3.3.5.2) . 127

Figure 6 – Diagram of the test circuit for the verification of making and breaking

capacities of a four-pole equipment (see 8.3.3.5.2) . 128

Figure 7 – Schematic illustration of the recovery voltage across contacts of the first
phase to clear under ideal conditions (see 8.3.3.5.2, item e)) . 129

Figure 8a – Diagram of a load circuit adjustment method: load star-point earthed . 130

Figure 8b – Diagram of a load circuit adjustment method: supply star-point earthed . 131

Figure 9 – Diagram of the test circuit for the verification of short-circuit making and

breaking capacities of a single-pole equipment on single-phase a.c. or on d.c. (see

8.3.4.1.2) . 132
Figure 10 – Diagram of the test circuit for the verification of short-circuit making and
breaking capacities of a two-pole equipment on single-phase a.c. or on d.c. (see
8.3.4.1.2) . 133
Figure 11 – Diagram of the test circuit for the verification of short-circuit making and
breaking capacities of a three-pole equipment (see 8.3.4.1.2) . 134
Figure 12 – Diagram of the test circuit for the verification of short-circuit making and
breaking capacities of a four-pole equipment (see 8.3.4.1.2). 135
Figure 13 – Example of short-circuit making and breaking test record in the case of a
single-pole equipment on single-phase a.c. (see 8.3.4.1.8) . 136
Figure 14 – Verification of short-circuit making and breaking capacities on d.c. (see
8.3.4.1.8) . 137
Figure 15 – Determination of the prospective breaking current when the first calibration
of the test circuit has been made at a current lower than the rated breaking capacity
(see 8.3.4.1.8, item b)) . 138
Figure 16 – Actuator test force (see 8.2.5.2.1 and Table 17) . 139
Figure 17 – Examples of ports . 140
Figure 18 – Test set-up for the verification of immunity to electrostatic discharges . 140
Figure 19 – Test set-up for the verification of immunity to radiated radio-frequency
electromagnetic fields . 141
Figure 20 – Test set-up for the verification of immunity to electrical
fast transients/bursts . 142
Figure 21 – Test set-up for the verification of immunity to conducted disturbances
induced by r.f. fields on power lines . 143
Figure 22 – Example of test set-up for the verification of immunity to conducted
disturbances induced by r.f. fields on signal lines when CDN´s are not suitable . 143

Figure 23 – Test set-up for the verification of immunity to power frequency magnetic
fields . 144
Figure C.1 – IP Codes . 155
Figure D.1 − Screw terminals clamping units . 159
Figure D.2 – Pillar terminals clamping units . 161
Figure D.3 − Stud terminals clamping units . 162
Figure D.4 – Saddle terminals clamping units . 163
Figure D.5 – Lug terminals clamping units . 164
Figure D.6 – Mantle terminals clamping units . 165
Figure D.7 – Screwless-type terminals clamping units . 167
Figure D.8 – Clamping unit in a connecting device . 158
Figure E.1 – Determination of the actual value of the factor γ . 169
Figure G.1 – Measurement of ribs . 173

– 6 – IEC 60947-1:2007
+AMD1:2010+AMD2:2014 CSV © IEC 2014

Figure G.2 – Creepage distance across the fixed and moving insulation of contact

carriers . 173

Figure K.1 – Plot of Weibull median rank regression . 190

Figure M.1 – Test fixture for hot wire ignition test. 202

Figure M.2 – Circuit for arc ignition test . 204

Figure N.1 – Example of application with component connected between separated

circuits . 211

Figure O.1 − Conceptual relationship between provisions in product standards and the
environmental impacts associated with the product during its life cycle . 224

Figure O.2 − Overview of ECD process . 225
Figure P.1 – Dimensions . 229
Figure R.1 – Operating mechanism outside the enclosure . 238
Figure R.2 – Operating space for push-button actuation. 239
Figure R.3 – Examples of finger protected location for hazardous-live-parts in push-
button vicinity (approximately 25 mm) . 240
Figure R.4 – Operating space for actuation by rotary means . 241
Figure S.1 – I/O parameters . 244
Figure S.2 – U-I operation regions of current-sinking inputs . 245
Figure S.3 – Temporary overload waveform for digital a.c. outputs . 247
Figure S.4 – Temporary overload waveform for digital d.c. outputs . 250
Figure T.1 – Test circuit for the verification of the operating characteristic of a
ground/earth fault current sensing electronic relay . 260
Figure U.1 – Diagrammatic representation of an external control device . 261
Figure U.2 – Single supply and control input . 262
Figure U.3 – Separate supply and control inputs . 262
Figure U.5 – Equipment with several external control supplies . 263
Figure U.6 – Equipment with bus interface . 263

+AMD1:2010+AMD2:2014 CSV © IEC 2014

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 1: General rules
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

This Consolidated version of IEC 60947-1 bears the edition number 5.2. It consists of the
fifth edition (2007-06) [documents 17B/1550/FDIS and 17B/1563/RVD], its amendment 1
(2010-12) [documents 17B/1710/FDIS and 17B/1721/RVD] and its amendment 2 (2014-09)
[documents 121A/15/FDIS and 121A/21/RVD]. The technical content is identical to the
base edition and its amendments.
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendments 1 and 2. Additions and deletions are displayed in red, with
deletions being struck through. A separate Final version with all changes accepted is
available in this publication.
This publication has been prepared for user convenience.

– 8 – IEC 60947-1:2007
+AMD1:2010+AMD2:2014 CSV © IEC 2014

International Standard IEC 60947-1 has been prepared by subcommittee 17B: Low-voltage

switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.

The main changes with respect to the previous edition are as follows:

– modification and restructuration of 7.1;

– introduction of new figures concerning EMC tests;

– introduction of new Annexes Q, R and S.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A vertical line in the margin shows where the base publication has been modified by the

Amendment 1.
A list of all the parts in the IEC 60947 series, under the general title Low-voltage switchgear
and controlgear can be found on the IEC website.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability 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.
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 publication using a colour printer.

+AMD1:2010+AMD2:2014 CSV © IEC 2014

LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –

Part 1: General rules
1 General
The purpose of this standard is to harmonize as far as practicable all rules and requirements of

a general nature applicable to low-voltage switchgear and controlgear in order to obtain
uniformity of requirements and tests throughout the corresponding range of equipment and to
avoid the need for testing to different standards.
All those parts of the various equipment standards which can be considered as general have
therefore been gathered in this standard together with specific subjects of wide interest and
application, e.g. temperature-rise, dielectric properties, etc.
For each type of low-voltage switchgear and controlgear, only two main documents are
necessary to determine all requirements and tests:
1) this basic standard, referred to as "Part 1" in the specific standards covering the various
types of low-voltage switchgear and controlgear;
2) the relevant equipment standard hereinafter referred to as the "relevant product standard"
or "product standard".
For a general rule to apply to a specific product standard, it shall be explicitly referred to by the
latter, by quoting the relevant clause or subclause number of this standard followed by
"IEC 60947-1" e.g. "7.2.3 of IEC 60947-1".
A specific product standard may not require, and hence may omit, a general rule (as being not
applicable), or it may add to it (if deemed inadequate in the particular case), but it may not
deviate from it, unless there is a substantial technical justification.
NOTE The product standards due to be part of forming the series of IEC standards covering low-voltage
switchgear and controlgear are:
IEC 60947-2: Part 2: Circuit-breakers
IEC 60947-3: Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units
IEC 60947-4: Part 4: Contactors and motor-starters

IEC 60947-5: Part 5: Control-circuit devices and switching elements
IEC 60947-6: Part 6: Multiple function equipment
IEC 60947-7: Part 7: Ancillary equipment
IEC 60947-8: Part 8: Control units for built-in thermal protection (PTC) for rotating electrical machines.
1.1 Scope and object
This standard applies, when required by the relevant product standard, to low-voltage
switchgear and controlgear hereinafter referred to as "equipment" or “device” and intended to
be connected to circuits, the rated voltage of which does not exceed 1 000 V a.c. or
1 500 V d.c.
It does not apply to low-voltage switchgear and controlgear assemblies which are dealt with in
IEC 60439.
– 10 – IEC 60947-1:2007
+AMD1:2010+AMD2:2014 CSV © IEC 2014

NOTE In certain clauses or subclauses of this standard, the equipment covered by this standard is also referred to

as "device", to be consistent with the text of such clauses or subclauses.

The object of This standard is to state those states the general rules and common safety

requirements which are common to for low-voltage equipment as defined in 1.1 switchgear and

controlgear, including for example:

– definitions;
– characteristics;
– information supplied with the equipment;

– normal service, mounting and transport conditions;

– constructional and performance requirements;
– verification of characteristics and performance;
– environmental aspects.
Digital inputs and/or digital outputs contained in switchgear and controlgear, and intended to be
compatible with programmable controllers (PLCs) are covered by Annex S.
This standard does not apply to low-voltage switchgear and controlgear assemblies which are
dealt with in IEC 61439 series, as applicable.
1.2 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 60050(151):2001, International Electrotechnical Vocabulary (IEV) – Chapter 151: Electrical
and magnetic devices
IEC 60050(441):1984, International Electrotechnical Vocabulary (IEV) – Chapter 441:
Switchgear, controlgear and fuses
Amendment 1 (2000)
IEC 60050(604):1987, International Electrotechnical Vocabulary (IEV) – Chapter 604:
Generation, transmission and distribution of electricity – Operation
Amendment 1 (1998)
IEC 60050(826):2004, International Electrotechnical Vocabulary (IEV) – Chapter 826: Electrical
installations
IEC 60060, High-voltage test techniques

IEC 60068-1:1988, Environmental testing − Part 1: General and guidance
Amendment 1 (1992)
IEC 60068-2-1:1990, Environmental testing − Part 2-1: Tests − Tests A: Cold
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-2:1974, Environmental testing − Part 2-2: Tests − Tests B: Dry heat
Amendment 1 (1993)
Amendment 2 (1994)
IEC 60068-2-6:1995, Environmental testing − Part 2-6: Tests − Test Fc: Vibration (sinusoidal)
IEC 60068-2-27:1987, Environmental testing − Part 2-27: Tests − Test Ea and guidance: Shock

+AMD1:2010+AMD2:2014 CSV © IEC 2014

− Part 2-30: Tests − Test Db: Damp heat, cyclic
IEC 60068-2-30:2005, Environmental testing

(12 h + 12 h cycle)
IEC 60068-2-52:1996, Environmental testing − Part 2-52: Tests − Test Kb: Salt mist, cyclic

(sodium chloride solution)
IEC 60068-2-78:2001, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady

state
IEC 60071-1:1993, Insulation co-ordination – Part 1: Definitions, principles and rules

IEC 60073:2002, Basic and safety principles for man-machine interface, marking and
identification – Coding principles for indicators and actuators
IEC 60085:2004, Electrical insulation – Thermal classification
IEC 60092-504:2001, Electrical installations in ships – Part 504: Special features – Control and
instrumentation
IEC 60112:2003, Method for the determination of the proof and the comparative tracking
indices of solid insulating materials
IEC 60216, Guide for the determination of thermal endurance properties of electrical insulating
materials
IEC 60228:2004, Conductors of insulated cables
IEC 60269-1:1998, Low-voltage fuses – Part 1: General requirements
Amendment 1 (2005)
IEC 60269-2:1986, Low-voltage fuses – Part 2: Supplementary requirements for fuses for use
by authorized persons (fuses mainly for industrial application)
Amendment 1 (1995)
Amendment 2 (2001)
IEC 60300-3-5:2001, Dependability management – Part 3-5: Application guide – Reliability test
conditions and statistical test principles
IEC 60344:1980, Guide to the calculation of resistance of plain and coated copper conductors
of low-frequency cables and wires
Amendment 1 (1985)
IEC 60364-4-44:2001, Electrical installations of buildings – Part 4-44: Protection for safety –
Protection against voltage disturbances and electromagnetic disturbances
Amendment 1 (2003)
IEC 60417-DB:2002 , Graphical symbols for use on equipment
IEC 60439-1:1999, Low-voltage switchgear and controlgear assemblies – Part 1: Type-tested
and partially type-tested assemblies
Amendment 1 (2004)
IEC 60445:1999, 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 of an alphanumeric system
___________
“DB” refers to the IEC on-line database.

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IEC 60447:2004, Basic and safety principles for man-machine interface, marking and

identification – Actuating principles

IEC 60529:1989, Degrees of protection provided by enclosures (IP code)

Amendment 1 (1999)
IEC 60617-DB:2001 , Graphical symbols for diagrams

IEC 60664-1:1992 2007, Insulation coordination for equipment within low-voltage systems –
...