IEC 60947-1:2020

Low-voltage switchgear and controlgear - Part 1: General rules

IEC 60947-1:2020 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 AC or 1 500 V DC.
This document states the general rules and common safety requirements for low-voltage switchgear and controlgear, including:
- definitions;
- characteristics;
- information supplied with the equipment;
- normal service, mounting and transport conditions, decommissioning and dismantling;
- constructional and performance requirements;
- verification of characteristics and performance;
- energy efficiency aspects (see Annex V);
- environmental aspects.
This sixth edition cancels and replaces the fifth edition published in 2007, Amendment 1:2010 and Amendment 2:2014. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
– DC values testing improvement;
– update of EMC tests;
– Annex B deletion;
– update of requirements for environmental tests (Table Q.1);
– improvement of Annex R (new examples);
– deletion of digital input Type 2, and introduction of Type 3 in Annex S;
– example for materials declaration (Annex W);
– new Annex X (co-ordination between short-circuit protective devices associated in the same circuit) created.
The contents of the corrigendum of December 2022 and April 2024 have been included in this copy.

Appareillage à basse tension – Partie 1: Règles générales

IEC 60947-1:2020 Lorsque la norme de produit correspondante l’exige, le présent document s’applique à l’appareillage basse tension ci-après désigné comme le “matériel” ou le “dispositif”, et destiné à être relié à des circuits dont la tension assignée ne dépasse pas 1 000 V en courant alternatif. ou 1 500 V en courant continu.
Le présent document a pour objet de fixer les règles générales et exigences de sécurité communes des appareillages basse tension, y compris:
– les définitions,
– les caractéristiques,
– les informations fournies avec le matériel,
– les conditions normales de service, de montage, de transport, de mise hors service et de démontage,
– les exigences relatives à la construction et au fonctionnement,
– la vérification des caractéristiques et du fonctionnement,
– les aspects liés à l’efficacité énergétique (voir Annexe V),
– les aspects environnementaux.
Cette sixième édition annule et remplace la cinquième édition parue en 2007, l'Amendement 1:2010 et l'Amendement 2:2014. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
– amélioration des essais relatifs aux valeurs en courant continu,
– mise à jour des essais de CEM,
– suppression de l’Annexe B,
– mise à jour des exigences des essais d’environnement (Tableau Q.1),
– amélioration de l’Annexe R (nouveaux exemples),
– suppression du type d’entrée numérique 2 et insertion du type 3 dans l’Annexe S,
– insertion d’un exemple de déclaration de matière dans l’Annexe W,
– création d’une nouvelle Annexe X (coordination des dispositifs de protection contre les courts-circuits associés dans un même circuit).
Le contenu du corrigendum de décembre 2022 et d'abril 2024 a été pris en considération dans cet exemplaire.

General Information

• Status: Published
• Publication Date: 21-Apr-2020
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SC 121A - Low-voltage switchgear and controlgear
• Drafting Committee: MT 5 - TC 121/SC 121A/MT 5
• Current Stage: PPUB - Publication issued
• Start Date: 22-Apr-2020
• Completion Date: 17-Apr-2020

Relations

• Corrected By: IEC 60947-1:2020/COR2:2024 - Corrigendum 2 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 12-Apr-2024
• Corrected By: IEC 60947-1:2020/COR1:2022 - Corrigendum 1 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-1:2007/AMD2:2014 - Amendment 2 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-1:2007/AMD1:2010 - Amendment 1 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 05-Sep-2023
• Revises: IEC 60947-1:2007 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60947-1 ®
Edition 6.0 2020-04
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 6.0 2020-04
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
INTERNATIONALE
ICS 29.130.20 ISBN 978-2-8322-8026-3

– 2 – IEC 60947-1:2020 © IEC 2020
CONTENTS
FOREWORD . 13
INTRODUCTION . 16
1 Scope . 17
2 Normative references . 17
3 Terms, definitions, symbols and reference clauses . 21
3.1 General . 21
3.2 Alphabetical index of definitions . 21
3.3 General terms and definitions . 26
3.4 Switching devices . 30
3.5 Parts of switching devices . 33
3.6 Operation of switching devices . 39
3.7 Characteristic quantities . 44
3.8 Tests . 54
3.9 Ports . 54
3.10 Symbols and references clauses for characteristics described
in this document. 54
4 Classification . 55
5 Characteristics . 55
5.1 Summary of the characteristics . 55
5.2 Type of equipment . 56
5.3 Rated and limiting values for the main circuit . 56
5.3.1 Rated voltages . 56
5.3.2 Currents . 57
5.3.3 Rated frequency . 58
5.3.4 Rated duties . 58
5.3.5 Characteristics under normal load and overload conditions (see 8.2.4) . 60
5.3.6 Short-circuit characteristics . 61
5.3.7 Pole impedance of the switching device (Z) . 62
5.4 Utilization category . 62
5.5 Control circuits . 62
5.5.1 Electrically or electronically controlled circuits . 62
5.5.2 Air-supply control circuits (pneumatic or electro-pneumatic) . 63
5.6 Auxiliary circuits . 63
5.7 Relays and releases . 63
5.8 Co-ordination with short-circuit protective devices (SCPD) . 63
6 Product information . 63
6.1 Nature of information . 63
6.2 Marking . 64
6.3 Instructions for installation, operation and maintenance, decommissioning
and dismantling. 65
6.4 Environmental information . 66
7 Normal service, mounting and transport conditions . 66
7.1 Normal service conditions . 66
7.1.1 Ambient air temperature . 66
7.1.2 Altitude . 67
7.1.3 Atmospheric conditions . 67

7.1.4 Shock and vibration . 68
7.2 Conditions during transport and storage . 68
7.3 Mounting . 68
8 Constructional and performance requirements . 68
8.1 Constructional requirements . 68
8.1.1 General . 68
8.1.2 Materials . 69
8.1.3 Current-carrying parts and their connections . 70
8.1.4 Clearances and creepage distances . 70
8.1.5 Actuator . 70
8.1.6 Indication of the contact position . 71
8.1.7 Additional requirements for equipment suitable for isolation . 71
8.1.8 Terminals . 73
8.1.9 Additional requirements for equipment provided with a neutral pole . 74
8.1.10 Provisions for protective earthing . 74
8.1.11 Dedicated enclosures for equipment . 76
8.1.12 Degrees of protection of enclosed equipment . 76
8.1.13 Conduit pull-out, torque and bending with metallic conduits . 76
8.2 Performance requirements . 77
8.2.1 Operating conditions . 77
8.2.2 Temperature-rise . 78
8.2.3 Dielectric properties . 79
8.2.4 Ability to make, carry and break currents under no-load, normal load
and overload conditions . 82
8.2.5 Ability to make, carry and break short-circuit currents . 83
8.2.6 Pole impedance . 83
8.2.7 Leakage currents of equipment suitable for isolation . 84
8.3 Electromagnetic compatibility (EMC) . 84
8.3.1 General . 84
8.3.2 Immunity . 84
8.3.3 Emission . 85
9 Tests . 85
9.1 Kinds of test . 85
9.1.1 General . 85
9.1.2 Type tests . 85
9.1.3 Routine tests . 86
9.1.4 Sampling tests . 86
9.1.5 Special tests . 86
9.2 Compliance with constructional requirements . 87
9.2.1 General . 87
9.2.2 Test of materials to abnormal heat and fire . 87
9.2.3 Equipment . 87
9.2.4 Enclosures for equipment . 87
9.2.5 Mechanical and electrical properties of terminals . 88
9.2.6 Verification of the effectiveness of indication of the main contact
position of equipment suitable for isolation . 90
9.2.7 Vacant . 93
9.2.8 Conduit pull-out test, torque test and bending test with metallic conduits . 93
9.2.9 Test of earth continuity for protective earth . 94

– 4 – IEC 60947-1:2020 © IEC 2020
9.3 Performance . 94
9.3.1 Test sequences . 94
9.3.2 General test conditions . 94
9.3.3 Performance under no-load, normal load and overload conditions . 96
9.3.4 Performance under short-circuit conditions . 109
9.4 Tests for EMC . 114
9.4.1 General . 114
9.4.2 Immunity . 114
9.4.3 Emission . 115
Annex A (informative) Harmonisation of utilization categories for low-voltage
switchgear and controlgear . 146
Annex B (Vacant) . 149
Annex C (normative) Degrees of protection of enclosed equipment . 150
C.1 General . 150
C.2 Object . 150
C.3 Definitions. 150
C.4 Designation . 150
C.5 Degrees of protection against access to hazardous parts and against ingress
of solid foreign objects indicated by the first characteristic numeral . 150
C.6 Degrees of protection against ingress of water indicated by the second
characteristic numeral . 150
C.7 Degrees of protection against access to hazardous parts indicated by the
additional letter . 151
C.8 Supplementary letters . 151
C.9 Examples of designations with IP Code . 151
C.10 Marking . 151
C.11 General requirements for tests . 151
C.12 Tests for protection against access to hazardous parts indicated by the first
characteristic numeral . 152
C.13 Tests for protection against ingress of solid foreign objects indicated by the
first characteristic numeral . 152
C.14 Tests for protection against water indicated by second characteristic
numeral . 153
C.14.1 Test means . 153
C.14.2 Test conditions . 153
C.14.3 Acceptance conditions . 153
C.15 Tests for protection against access to hazardous parts indicated by
additional letter . 153
C.16 Summary of responsibilities of relevant technical committees . 153
Annex D (informative) Examples of clamping units and relationship between clamping
unit and connecting device. 157
D.1 Clamping unit in a connecting device . 157
D.2 Examples of clamping units . 158
Annex E (informative) Description of a method for adjusting the load circuit . 165
Annex F (informative) Determination of short-circuit power-factor or time-constant . 167
F.1 Determination of short-circuit power-factor . 167
F.1.1 Method I – Determination from DC component . 167
F.1.2 Method II – Determination with pilot generator . 167
F.2 Determination of short-circuit time-constant (oscillographic method) . 168
Annex G (informative) Measurement of creepage distances and clearances . 169

G.1 Basic principles . 169
G.2 Use of ribs . 169
Annex H (informative) Correlation between the nominal voltage of the supply system
and the rated impulse withstand voltage of equipment . 176
(informative) Items subject to agreement between manufacturer and user . 178
Annex K (normative) Procedure to determine reliability data for electromechanical
devices used in functional safety applications . 179
K.1 General . 179
K.1.1 Overview . 179
K.1.2 Object . 179
K.1.3 General requirements . 179
K.2 Terms, definitions and symbols . 180
K.2.1 Terms and definitions . 180
K.2.2 Symbols . 181
K.3 Method based on durability test results . 181
K.3.1 General method . 181
K.3.2 Test requirements . 181
K.3.3 Number of samples . 181
K.3.4 Characterization of a failure mode . 181
K.3.5 Weibull modelling . 182
K.3.6 Useful life and upper limit of failure rate . 184
K.3.7 Reliability data . 185
K.4 Data information . 185
K.5 Example. 186
K.5.1 Test results. 186
K.5.2 Weibull distribution and median rank regression . 186
K.5.3 Useful life and failure rate . 187
Annex L (normative) Terminal marking and distinctive number . 189
L.1 General . 189
L.2 Terminal marking of impedances (alphanumerical) . 189
L.2.1 Coils . 189
L.2.2 Electromagnetic releases . 190
L.2.3 Interlocking electromagnets . 190
L.2.4 Indicating light devices . 191
L.3 Terminal marking of contact elements for switching devices with two
positions (numerical) . 191
L.3.1 Contact elements for main circuits (main contact elements) . 191
L.3.2 Contact elements for auxiliary circuit (auxiliary contact elements) . 191
L.4 Terminal marking of overload protection devices . 193
L.5 Distinctive number . 194
L.6 Marking of terminals for external associated electronic circuit components,
contacts and complete devices . 194
L.6.1 Marking of terminals for external associated electronic circuit
components and contacts . 194
L.6.2 Marking of terminals for external complete devices . 197
Annex M (normative) Flammability test . 200
M.1 Hot wire ignition test (HWI) . 200
M.1.1 Test sample . 200
M.1.2 Description of test apparatus . 200

– 6 – IEC 60947-1:2020 © IEC 2020
M.1.3 Conditioning . 201
M.1.4 Test procedure . 201
M.2 Arc ignition test (AI) . 201
M.2.1 Test sample . 201
M.2.2 Description of test apparatus . 201
M.2.3 Conditioning . 202
M.2.4 Test procedure . 202
M.3 HWI and AI requirements . 203
Annex N (normative) Requirements and tests for equipment with protective separation . 204
N.1 General . 204
N.2 Terms and definitions . 204
N.3 Requirements . 206
N.3.1 General . 206
N.3.2 Dielectric requirements . 206
N.3.3 Construction requirements . 206
N.4 Tests . 207
N.4.1 General . 207
N.4.2 Dielectric tests . 207
N.4.3 Examples of constructional measures . 207
Annex O (informative) Environmentally conscious design . 209
O.1 General . 209
O.2 Object . 209
O.3 Terms and definitions . 210
O.4 General considerations . 212
O.5 Fundamentals requirements of environmentally conscious design (ECD) . 215
O.6 Environmentally conscious design process (ECD process) . 216
O.6.1 General . 216
O.6.2 Process steps of ECD . 216
O.7 Tools for including ECD in product design and development . 217
O.8 Relevant ISO technical committees . 217
Annex P (informative) Terminal lugs for low voltage switchgear and controlgear
connected to copper conductors . 218
Annex Q (normative) Special tests – Tests for environmental categories . 219
Q.1 General . 219
Q.2 Classification of equipment . 219
Q.3 Tests . 220
Q.3.1 General test conditions . 220
Q.3.2 Test sequences . 220
Annex R (normative) Application of the metal foil for dielectric testing on accessible
parts during operation or adjustment . 225
R.1 General . 225
R.2 Object . 225
R.3 Definition of zones . 226
R.3.1 General . 226
R.3.2 Application of metal foil on accessible parts during normal operation or
adjustment . 226
Annex S (normative) Digital inputs and outputs . 233
S.1 General . 233
S.2 Terms and definitions . 233

S.3 Functional requirements . 233
S.3.1 Rated values and operating ranges . 233
S.3.2 Digital I/Os . 234
S.4 Verification of input/output requirements . 242
S.4.1 General . 242
S.4.2 Verification of digital inputs . 243
S.4.3 Verification of digital outputs . 243
S.4.4 Behaviour of the equipment . 244
S.5 General information to be provided by the manufacturer . 245
S.5.1 Information on digital inputs (current sinking). 245
S.5.2 Information on digital outputs for alternating currents (current sourcing) . 245
S.5.3 Information on digital outputs for direct current (current sourcing) . 246
S.6 Digital input standard operating range equations. 246
Annex T (normative) Extended functions within electronic overload relays . 248
T.1 Object . 248
T.1.1 General . 248
T.1.2 Ground/earth fault detection function . 248
T.2 Terms and definitions . 248
T.3 Classification of electronic overload relays . 249
T.4 Types of relays with ground/earth fault detection function . 249
T.5 Performance requirements . 249
T.5.1 Limits of operation of ground/earth fault electronic overload relays . 249
T.5.2 Limits of operation of ground/earth fault current sensing electronic
relays Type CII(-A and -B) . 250
T.5.3 Limits of operation of voltage asymmetry relays . 250
T.5.4 Limits of operation of phase reversal relays . 250
T.5.5 Limits of operation of current imbalance relays . 250
T.5.6 Limits of operation of over-voltage relays and releases . 250
T.6 Tests . 251
T.6.1 Limits of operation of ground/earth fault current sensing electronic
relays Types CI and CII (-A and -B) . 251
T.6.2 Verification of inhibit function of ground/earth fault current sensing
electronic relays Type CII (-A and -B) . 251
T.6.3 Current asymmetry relays . 251
T.6.4 Voltage asymmetry relays . 251
T.6.5 Phase reversal relays . 251
T.6.6 Over-voltage relays . 252
T.7 Routine and sampling tests . 252
Annex U (informative) Examples of control circuit configurations . 253
U.1 External control device. 253
U.1.1 Definition . 253
U.1.2 Diagrammatic representation of an external control device . 253
U.1.3 Parameters of an external control device . 253
U.2 Control circuit configurations . 254
U.2.1 Equipment with external control supply . 254
U.2.2 Equipment with several external control supplies . 254
U.2.3 Equipment with bus interface (may be combined with other circuit
configurations) . 255
Annex V (informative) Power management with switchgear and controlgear for
electrical energy efficiency . 256

– 8 – IEC 60947-1:2020 © IEC 2020
V.1 General . 256
V.2 Object . 256
V.3 Terms and definitions . 256
V.4 Electrical energy efficiency and safety . 257
V.5 Principles on electrical energy efficiency (system approach) . 257
V.5.1 General . 257
V.5.2 Strategy of energy management . 257
V.5.3 Power management with automation and control . 257
V.6 Energy efficiency application . 258
V.6.1 Saving of semiconductor losses . 258
V.6.2 Power factor correction . 258
V.6.3 Load shedding . 258
V.6.4 Motor control for fixed speed applications . 258
Annex W (normative) Procedure to establish material declaration . 259
W.1 General . 259
W.2 Object . 259
W.3 Reference document . 259
W.4 Terms and definitions . 259
W.5 Material declaration requirements . 260
W.5.1 General reporting requirements . 260
W.5.2 Additional reporting requirements . 261
W.6 Example of material declaration made according to W.5 . 261
Annex X (normative) Co-ordination between circuit-breaker or CPS and another short-
circuit protective device associated in the same circuit . 267
X.1 General . 267
X.2 Object . 267
X.3 General requirements for the co-ordination of a circuit-breaker or CPS with
another SCPD . 268
X.3.1 General considerations . 268
X.3.2 Take-over current (I ) . 268
B
X.3.3 Behaviour of C in association with another SCPD . 268
X.4 Type and characteristics of the associated SCPD . 268
X.5 Verification of selectivity . 269
X.5.1 General . 269
X.5.2 Consideration of selectivity by desk study . 269
X.5.3 Selectivity determined by test . 270
X.6 Verification of back-up protection . 271
X.6.1 Determination of the take-over current . 271
X.6.2 Verification of back-up protection . 271
X.6.3 Tests for verification of back-up protection . 271
X.6.4 Results to be obtained . 272
Bibliography . 278

Figure 1 – Test equipment for flexion test (see 9.2.5.3 and Table 5) . 131
Figure 2 – Gauges of form A and form B (see 9.2.5.5.2 and Table 7) . 131
Figure 3 – Diagram of the test circuit for the verification of making and breaking
capacities of a single-pole equipment on single-phase AC or on direct curren
...