IEC 62991:2022

IEC 62991 ®
Edition 1.0 2022-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Particular requirements for source switching equipment (SSE)

Exigences particulières relatives au matériel de commutation de source (SSE)

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IEC 62991 ®
Edition 1.0 2022-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Particular requirements for source switching equipment (SSE)

Exigences particulières relatives au matériel de commutation de source (SSE)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 03.100.70; 27.015; 29.020 ISBN 978-2-8322-6198-9

– 2 – IEC 62991:2022 © IEC 2022
CONTENTS
FOREWORD . 8
INTRODUCTION . 10
1 Scope . 12
2 Normative references . 13
3 Terms and definitions . 15
3.1 General definitions . 15
3.2 Additional definitions for NC-SSE and SSE control units (controllers) of
C-SSE . 25
3.3 Additional definitions dedicated to C-SSE . 26
4 Classification . 27
4.1 According to the method of operation . 27
4.2 According to the construction . 27
4.3 According to the kind of current . 28
4.4 According to the number of switched poles . 28
4.5 According to the type of terminals . 28
4.6 According to the SSE's intended application . 28
4.7 According to coupling method . 28
4.7.1 SSE with synchronization . 28
4.7.2 SSE with interlock . 28
4.7.3 SSE with synchronization and interlock . 28
4.8 According to the transition type . 28
4.9 According to the possibility to select sources . 28
4.10 According to the utilization category . 28
4.11 According to the possibility to provide an OFF position . 28
4.12 According to the method of mounting . 29
4.13 According to the protection against external influences . 29
4.14 According to functional categories . 29
5 Characteristics . 31
5.1 General . 31
5.2 Type and characteristics of the equipment . 32
5.3 Characteristics of NC-SSE . 32
5.3.1 General . 32
5.3.2 Characteristics of main circuits . 32
5.3.3 Utilization categories . 35
5.3.4 Characteristics of control circuits, including electrical interlocks . 35
5.3.5 Characteristics of auxiliary circuits . 37
5.4 Characteristics of C-SSE . 37
5.4.1 General . 37
5.4.2 Characteristics of main circuits . 37
5.4.3 Utilization categories . 38
5.4.4 Characteristics of control circuits, including electrical interlocks . 38
5.4.5 Characteristics of auxiliary circuits . 39
6 Markings and product information . 39
7 Standard conditions for operation in service . 40
7.1 General . 40
7.2 Ambient temperature range in normal use . 41

7.3 Relative humidity . 41
7.4 Altitude . 41
7.5 Conditions of installation . 41
7.6 Pollution degree . 41
8 Requirements for construction and operation . 41
8.1 General . 41
8.2 Mechanical design . 42
8.2.1 General . 42
8.2.2 Constructional requirements . 42
8.2.3 Mechanism and operating means. 44
8.2.4 Clearances and creepage distances and distances through sealing
compound . 46
8.2.5 Screws, current-carrying parts and connections . 49
8.2.6 Terminals for external conductors . 50
8.3 Protection against electric shock . 52
8.4 Dielectric properties . 52
8.4.1 General . 52
8.4.2 Dielectric properties . 52
8.5 Temperature-rise . 52
8.6 Making and breaking capacity . 53
8.7 Performances . 54
8.7.1 General . 54
8.7.2 Operating conditions . 55
8.7.3 Operational performance . 57
8.8 Resistance to heat . 58
8.9 Resistance of insulating material to abnormal heat and to fire . 58
8.10 Resistance to rusting . 59
8.11 Coordination with short-circuit protective devices (SCPDs) . 59
8.12 EMC . 59
8.13 Resistance to abnormal conditions .
...