AS 3947.2-1997

1 - AS 3947.2-1997 LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR - CIRCUIT-BREAKERS
4 - PREFACE
6 - CONTENTS
9 - 1 General
9 - 1.1 Scope and object
10 - 1.2 Normative references
12 - 2 Definitions
12 - 2.1 circuit-breaker:
12 - 2.1.1 frame size:
12 - 2.1.2 construction break:
12 - 2.2 integrally fused circuit-breaker:
12 - 2.3 current-limiting circuit-breaker:
12 - 2.4 plug-in circuit-breaker:
12 - 2.5 withdrawable circuit-breaker:
13 - 2.6 moulded-case circuit-breaker:
13 - 2.7 air circuit-breaker:
13 - 2.8 vacuum circuit-breaker:
13 - 2.9 gas circuit-breaker:
13 - 2.10 making-current release:
13 - 2.11 short-circuit release:
13 - 2.12 short-time delay short-circuit release:
13 - 2.13 alarm switch:
13 - 2.14 circuit-breaker with lock-out device preventing closing:
13 - 2.15 short-circuit breaking (or making) capacity:
13 - 2.15.1 ultimate short-circuit breaking capacity:
13 - 2.15.2 service short-circuit breaking capacity:
13 - 2.16 opening time:
13 - 2.17 over-current protective co-ordination:
13 - 2.17.1 over-current discrimination:
14 - 2.17.2 total discrimination (total selectivity):
14 - 2.17.3 partial discrimination (partial selectivity):
14 - 2.17.4 selectivity limit current (Is):
14 - 2.17.5 back-up protection:
14 - 2.17.6 take-over current (IB):
14 - 2.18 I2t characteristic of a circuit-breaker
14 - 3 Classification
15 - 4 Characteristics of circuit-breakers
15 - 4.1 Summary of characteristics
15 - 4.2 Type of circuit-breaker
15 - 4.2.1 Number of poles
15 - 4.2.2 Kind of current
15 - 4.3 Rated and limiting values of the main circuit
16 - 4.3.1 Rated voltages
16 - 4.3.2 Currents
16 - 4.3.3 Rated frequency
17 - 4.3.4 Rated duty
17 - 4.3.5 Short-circuit characteristics
19 - 4.4 Utilization categories
20 - 4.5 Control circuits
20 - 4.5.1 Electrical control circuits
20 - 4.5.2 Air-supply control circuits (pneumatic or electro-pneumatic)
20 - 4.6 Auxiliary circuits
21 - 4.7 Releases
21 - 4.7.1 Types
21 - 4.7.2 Characteristics
21 - 4.7.3 Current setting of over-current releases
22 - 4.7.4 Tripping time setting of over-current releases
22 - 4.8 Integral fuses (integrally fused circuit-breakers)
22 - 4.9 Switching overvoltages
22 - 5 Product information
22 - 5.1 Nature of the information
23 - 5.2 Marking
24 - 5.3 Instructions for installation, operation and maintenance
24 - 6 Normal service, mounting and transport conditions
24 - 7 Constructional and performance requirements
24 - 7.1 Constructional requirements
24 - 7.1.1 Withdrawable circuit-breakers
25 - 7.1.2 Additional requirements for circuit-breakers suitable for isolation
25 - 7.1.3 Clearances and creepage distances
25 - 7.1.4 Requirements for the safety of the operator
25 - 7.1.5 List of construction breaks
26 - 7.2 Performance requirements
26 - 7.2.1 Operating conditions
28 - 7.2.2 Temperature-rise
29 - 7.2.3 Dielectric properties
29 - 7.2.4 Ability to make and break under no load, normal load and overload conditions
30 - 7.2.5 Ability to make and break under short-circuit conditions
30 - 7.2.6 Switching overvoltages
30 - 7.2.7 Additional requirements for circuit-breakers suitable for isolation
30 - 7.2.8 Specific requirements for integrally fused circuit-breakers
31 - 7.2.9 Coordination between a circuit-breaker and another short-circuit protective device
31 - 7.3 Electromagnetic compatibility (EMC)
31 - 7.3.1 General
31 - 7.3.2 Immunity
31 - 7.3.3 Emission
32 - 8 Tests
32 - 8.1 Kind of tests
32 - 8.1.1 The tests to verify the characteristics of circuit-breakers are:
32 - 8.1.2 Type tests include the following tests:
32 - 8.1.3 Routine or sampling tests include the following tests:
32 - 8.2 Compliance with constructional requirements
33 - 8.3 Type tests
33 - 8.3.1 Test sequences
36 - 8.3.2 General test conditions
44 - 8.3.3 Test sequence I: General performance characteristics
53 - 8.3.4 Test sequence II: Rated service short-circuit breaking capacity
54 - 8.3.5 Test sequence III: Rated ultimate short-circuit breaking capacity
56 - 8.3.6 Test sequence IV: Rated short-time withstand current
57 - 8.3.7 Test sequence V: Performance of integrally fused circuit-breakers
59 - 8.3.8 Combined test sequence
60 - 8.3.9 Immunity tests for circuit-breakers incorporating electronic circuits, other than circuit-breakers according to annex
60 - 8.4 Routine tests
61 - 8.4.1 Mechanical operation tests
61 - 8.4.2 Verification of the calibration of overcurrent releases
61 - 8.4.3 Verification of the operation of undervoltage and shunt releases
62 - 8.4.4 Additional tests for CBRs
62 - 8.4.5 Dielectric tests
62 - 8.4.6 Test for the verification of clearances less than those corresponding to case A of table 13 of part 1
64 - Annex A - Coordination under short-circuit conditions between a circuit-breaker and another short-circuit protective device
64 - A.1 Introduction
65 - A.2 Scope and object
65 - A.3 General requirements for the coordination of a circuit-breaker with another SCPD
65 - A.4 Type and characteristics of the associated SCPD
66 - A.5 Verification of discrimination
66 - A.6 Verification of back-up protection
73 - Annex B - Circuit-breakers incorporating residual current protection
73 - INTRODUCTION
73 - B.1 Scope and object
74 - B.2 Definitions
75 - B.3 Classification
76 - B.4 Characteristics of CBRs concerning their residual current function
78 - B.5 Marking
79 - B.6 Normal service, mounting and transport conditions
79 - B.7 Design and operating requirements
83 - B.8 Tests
107 - Annex C - Individual pole short-circuit test sequence
107 - C.1 General
107 - C.2 Test of individual pole short-circuit breaking capacity
107 - C.3 Verification of dielectric withstand
107 - C.4 Verification of overload releases
108 - Annex D - Clearances and creepage distances
108 - D.1 General
108 - D.2 Determination of clearances and creepage distances
109 - Annex E - Items subject to agreement between manufacturer and user
110 - Annex F - Additional requirements for circuit-breakers with electronic over-current protection
110 - F.1 Scope
110 - F.2 List of tests
111 - F.3 General test conditions
112 - F.4 Immunity tests regarding low-frequency disturbances in power supply networks
115 - F.5 Immunity tests regarding conducted transients and high-frequency disturbances
116 - F.6 Immunity tests regarding electrostatic disturbances
117 - F.7 Immunity tests regarding electromagnetic field disturbances
118 - F.8 Dry heat test
119 - F.9 Thermal shock test
119 - F.10 Damp heat test
119 - F.11 Tests for radiated radiofrequency emissions
125 - Annex G - Power loss
125 - G.1 General
125 - G.2 Test methods
126 - G.3 Test procedure
128 - Annex H - Test sequence for circuit-breakers for IT systems
128 - H.1 General
128 - H.2 Individual pole short circuit
129 - H.3 Verification of dielectric withstand
129 - H.4 Verification of overload releases
129 - H.5 Marking

Specifies requirements for circuit-breakers, the main contacts of which are intended to be connected to circuits, the rated voltage of which does not exceed 1000 volt a.c. or 1500 volt d.c. It includes requirements for co-ordination under short-circuit conditions between a circuit-breaker and another short-circuit protective device associated in the same circuit. This Standard is identical with and has been reproduced from IEC 947-2:1995.

This standard applies to circuit-breakers, the main contacts of which are 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 also contains additional requirements for integrally fused circuit-breakers.It applies whatever the rated currents, the method of construction or the proposed applications of the circuit-breakers may be.The requirements for circuit-breakers which are also intended to provide earth-leakage protection are contained in annex B.The additional requirements for circuit-breakers with electronic over-current protection are contained in annex F.The additional requirements for circuit-breakers for IT systems are contained in annex H.Supplementary requirements for circuit-breakers used as direct-on-line starters are given in IEC 947-4-1, applicable to low-voltage contactors and starters.The requirements for circuit-breakers for the protection of wiring installations in buildings and similar applications, and designed for use by uninstructed persons, are contained in IEC 898.The requirements for circuit-breakers for equipment (for example electrical appliances) are contained in IEC 934.For certain specific applications (for example traction, rolling mills, marine service) particular or additional requirements may be necessary.NOTE - Circuit-breakers which are dealt with in this standard may be provided with devices for automatic opening under predetermined conditions other than those of over-current and undervoltage as, for example, reversal of power or current. This standard does not deal with the verification of operation under such predetermined conditions.The object of this standard is to state:a) the characteristics of circuit-breakers;b) the conditions with which circuit-breakers shall comply with reference to:1) operation and behaviour in normal service;2) operation and behaviour in case of overload and operation and behaviour in case of short-circuit, including co-ordination in service (discrimination and back-up protection);3) dielectric properties;c) tests intended for confirming that these conditions have been met and the methods to be adopted for these tests;d) information to be marked on or given with the apparatus.

First published as AS 3858-1990.
Revised and redesignated AS 3947.2-1997.