IEC 60947-2:2006/AMD2:2013

IEC 60947-2
®

Edition 4.0 2013-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
AMENDMENT 2
AMENDEMENT 2

Low-voltage switchgear and controlgear –
Part 2: Circuit-breakers

Appareillage à basse tension –
Partie 2: Disjoncteurs

IEC 60947-2:2006/A2:2013

---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60947-2

®


Edition 4.0 2013-01




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside



AMENDMENT 2

AMENDEMENT 2





Low-voltage switchgear and controlgear –

Part 2: Circuit-breakers




Appareillage à basse tension –

Partie 2: Disjoncteurs
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE

PRICE CODE
INTERNATIONALE

CODE PRIX R


ICS 29.130.20 ISBN 978-2-83220-578-5



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® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

---------------------- Page: 3 ----------------------
– 2 – 60947-2 Amend. 2  IEC:2013
FOREWORD
This amendment has been prepared by subcommittee 17B: Low-voltage switchgear and
controlgear, of IEC technical committee 17: Switchgear and controlgear.
The text of this amendment is based on the following documents:
FDIS Report on voting
17B/1796/FDIS 17B/1807/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 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• withdrawn,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 document using a
colour printer.

_____________
CONTENTS
Delete the entry referring to Table 1.
1.1 Scope and object
Replace the existing item b)2) of this subclause by the following new item b)2):
2) operation and behaviour in case of overload and operation and behaviour in case of
short-circuit, including co-ordination in service (selectivity and back-up protection);

2 Definitions
2.17.1
over-current discrimination
Replace the existing term and definition by the following new term and definition, and delete
the source:

---------------------- Page: 4 ----------------------
60947-2 Amend. 2  IEC:2013 – 3 –
over-current selectivity
co-ordination of the operating characteristics of two or more over-current protective devices such that,
on the incidence of over-currents within stated limits, the device intended to operate within
these limits does so, while the other(s) does (do) not
2.17.2
total discrimination (total selectivity)
Replace the existing term by the following new term:
total selectivity
Replace in the existing definition the word “discrimination” by the word “selectivity”.
2.17.3
partial discrimination (partial selectivity)
Replace the existing term by the following new term:
partial selectivity
Replace in the existing definition the word “discrimination” by “selectivity”.

Renumber the existing definition 2.21, added by Amendment 1, as definition 2.22.
Add, after 2.20, the following new definition 2.21:
2.21
overload current setting
I
r
current setting of an adjustable overload release
NOTE In case of a non-adjustable overload release, this value is equal to nominal current I .
n
4.3.1.1 Rated operational voltage (U )
e
This correction does not apply to the English version.
)
4.3.5.1 Rated short-circuit making capacity (I
cm
This correction does not apply to the English version.
4.3.5.2 Rated short-circuit breaking capacities
This correction does not apply to the English version.
)
4.3.5.2.1 Rated ultimate short-circuit breaking capacity (I
cu
This correction does not apply to the English version.
)
4.3.5.2.2 Rated service short-circuit breaking capacity (I
cs
Replace the text of the existing subclause, including Table 1, by the following new text:
The rated service short-circuit breaking capacity of a circuit-breaker is the value of service
short-circuit breaking capacity (see 2.15.2) assigned to that circuit-breaker by the
manufacturer for the corresponding rated operational voltage, under the conditions specified
in 8.3.4. It is expressed as a value of prospective breaking current, in kA, or as a % of I
cu
(for example I = 25 % I ).
cs cu

---------------------- Page: 5 ----------------------
– 4 – 60947-2 Amend. 2  IEC:2013
I shall be at least equal to 25 % of I .
cs cu
Table 1 (void)

Table 4 – Selectivity categories
Replace the existing text of note 2 by the following new text:
NOTE 2 Vacant.
5.2 Marking
This correction does not apply to the English version.
Add, at the end of the existing item b), the following two new bulleted items:
• range of the current setting (I ) of adjustable overload release (see 4.7.3);
r
• value or range of the rated instantaneous short-circuit current setting (I ), fixed or
i
adjustable (see 4.7.3).
This correction does not apply to the English version.
Add, at the end of the existing item c), the following new bulleted items:
• minimum cable cross-section, if different from Table 9 of IEC 60947-1, for ratings ≤ 20 A
according to rated ultimate short-circuit breaking capacity I ;
cu
• values of tightening torque for the circuit-breaker terminals.

7.1.5 List of construction breaks
Replace the first dashed item by the following new dashed item:
– material, finish and dimensions of internal current-carrying parts, admitting, however, the
variations listed in a), b), c), f) and g) below;
Replace the item f) introduced by Amendment 1 by the following new item f):
f) in the case of the 2-pole and 4-pole variants, replacement of the trip unit in one pole by a
link, to provide an unprotected neutral;
Add, at the end of the existing list, the following new item g):
g) creating a 2-pole breaker from a 3-pole breaker by removing the centre current path.

8.3.1.2 Tests omitted from sequence I and made separately
Replace, in this subclause introduced by Amendment 1, the existing first dashed item by the
following new dashed item:
– tripping limits and characteristics (8.3.3.1); in which case the sample(s) tested in the
sequence shall be subjected to the tests of 8.3.3.1.3, only on the phase poles at the
maximum setting, at room temperature and without the additional test of item b) to verify
the time-current characteristic;

---------------------- Page: 6 ----------------------
60947-2 Amend. 2  IEC:2013 – 5 –

8.3.1.4 Alternative test programmes for circuit-breakers having both three-pole and
four-pole variants
Replace the existing title and text of this subclause, introduced by Amendment 1, including
Table 9b and Table 9c, by the following new title, text and Table 9b, Table 9c:
8.3.1.4 Alternative test programmes for circuit-breakers of a given frame size and
design having a different number of poles
These alternative test programmes may only be applied when all ratings are the same or
lower than the variant submitted to the full programme of Table 9, and construction breaks are
the same for all variants. In the case of 1-pole circuit-breakers the voltage ratings shall be
equal to or lower than the line-to neutral voltage of the variant tested to Table 9. A 2-pole
circuit-breaker produced by removing the centre current path from a 3-pole circuit-breaker
tested to Programme 1 or Programme 2 of this clause need not be tested as it is considered
to be covered by the tests on the 3-pole variant.
Compliance with the test requirements is met by carrying out one of the alternative
programmes 1 or 2 below.
– Programme 1: The applicable test sequences according to Table 9 shall be carried out
on the three-pole variant. In addition, where applicable, the tests or test sequences listed
in Table 9b shall be carried out on the other variants.
– Programme 2: The applicable test sequences according to Table 9 shall be carried out
on the four-pole variant. In addition, where applicable, the tests or test sequences listed in
Table 9c shall be carried out on the other variants.
The principle for the application of the alternative test programmes is illustrated below:
Programme 1 Programme 2
1-pole 2-poles 3-poles 4-poles 1-pole 2-poles 3-poles 4-poles
a
Construction 1
     
 
Construction 2
- -  - - -
 
Construction 3
- -  - - -
 
...
- -  - - -
 
Construction n
- -   - - - 
NOTE
 fully tested per Table 9
 tested per Table 9b
 tested per Table 9c
- no test required
a
construction 1 is the construction which covers the max rating.

---------------------- Page: 7 ----------------------
– 6 – 60947-2 Amend. 2  IEC:2013
Table 9b – Applicability of tests or test sequences to 1, 2 and 4-pole circuit-breakers
according to the alternative programme 1 of 8.3.1.4
Test Test clause Test Applicability to Applicability to
,
f h
sequence 1-pole or 2-pole
4-pole variant
g
variants
8.3.3.1 Test of tripping limits and characteristics
8.3.3.1.1 General X X
a e
8.3.3.1.2 Short-circuit releases X X
k
8.3.3.1.3a) Overload releases:
−instantaneous/definite time-delay X
or

k e
8.3.3.1.3b) X
−inverse time-delay
X
(as
applicable)
8.3.3.1.4 Additional test for definite time-delay releases:
8.3.3.2 Dielectric properties X X
8.3.3.3 Mechanical operation and operational performance capability
I
8.3.3.3.1 General X X
d d, e
8.3.3.3.2 Construction and mechanical operation X X
8.3.3.3.3 Operational performance capability without current X X
8.3.3.3.4 Operational performance capability with current X X
8.3.3.3.5 Withdrawable circuit-breakers X
8.3.3.4 Overload performance X X
8.3.3.5 Verification of dielectric withstand X X
8.3.3.6 Verification of temperature-rise X X
8.3.3.7 Verification of overload releases
8.3.3.8 Verification of undervoltage and shunt releases X X
8.3.3.9 Verification of the main contact position X X
II 8.3.4 Rated service short-circuit breaking capacity
b, c
Rated ultimate short-circuit breaking capacity
III X X
8.3.5
X
4th pole and
IV 8.3.6 Rated short-time withstand current adjacent pole
only
(see 8.3.2.6.4)
V 8.3.7 Performance of integrally fused circuit-breakers X X
VI 8.3.8 Combined test sequence
Annex C Individual pole short-circuit test sequence
Annex H Test sequence for circuit-breakers for IT systems
NOTE The applicability of a test or test sequence is indicated by X in the relevant space.

---------------------- Page: 8 ----------------------
60947-2 Amend. 2  IEC:2013 – 7 –
a
One test on one pair of phase poles chosen at random. In the case of an electronic trip unit, this test may be made on
one pole chosen at random.
b
This test sequence also applies when, for the 3-pole testing, Sequence III on the 3-poles variant is replaced by
Sequence II or Sequence VI (see Table 9).
c
One sample of maximum current rating only, tested at max kVA rating (I × corresponding U ).
cu e
d
Without verification tests of items c) (undervoltage releases) and d) (shunt releases).
e
Applicable only to 1-pole variant; not required for 2-poles variants.
f
In case of 4-poles devices with different levels of neutral protection (e.g. 60 % or 100 %), only the variant with the
highest level has to be tested according to Table 9b.
g
One sample of maximum current rating only, for each test sequence.
h
One sample of maximum current rating for each test sequence; in the case of one or more construction breaks (see
2.1.2 and 7.1.5) within the frame size, a further sample is tested at the maximum rated current corresponding to each
construction.
i
Vacant.
j
Vacant.
k
This test is not required for electronic trip units.

---------------------- Page: 9 ----------------------
– 8 – 60947-2 Amend. 2  IEC:2013
Table 9c – Applicability of tests or test sequences to 1, 2 and 3-pole circuit-breakers
according to the alternative programme 2 of 8.3.1.4
Test Test clause Test Applicability to Applicability to
g
sequence 3-pole variant 1-pole or 2-pole
g
variants
8.3.3.1 Test of tripping limits and characteristics
8.3.3.1.1 General X
e
8.3.3.1.2 Short-circuit releases X
k
8.3.3.1.3a) Overload releases:
- instantaneous/definite time-delay
or
k e
8.3.3.1.3b) - inverse time-delay X
(as
applicable)
8.3.3.1.4 Additional test for definite time-delay releases
8.3.3.2 Dielectric properties X X
8.3.3.3 Mechanical operation and operational performance capability
I
8.3.3.3.1 General X X
d, e
8.3.3.3.2 Construction and mechanical operation X
8.3.3.3.3 Operational performance capability without current X X
8.3.3.3.4 Operational performance capability with current X X
8.3.3.3.5 Withdrawable circuit-breakers
8.3.3.4 Overload performance X X
8.3.3.5 Verification of dielectric withstand X X
8.3.3.6 Verification of temperature-rise X X
8.3.3.7 Verification of overload releases
8.3.3.8 Verification of undervoltage and shunt releases X X
8.3.3.9 Verification of the main contact position X X
II 8.3.4 Rated service short-circuit breaking capacity
b, c
Rated ultimate short-circuit breaking capacity X
III X
8.3.5
IV 8.3.6 Rated short-time withstand current
V 8.3.7 Performance of integrally fused circuit-breakers X X
VI 8.3.8 Combined test sequence
Annex C Individual pole short-circuit test sequence
Annex H Test sequence for circuit-breaker for IT systems

NOTE The applicability of a test or test sequence is indicated by X in the relevant space.

---------------------- Page: 10 ----------------------
60947-2 Amend. 2  IEC:2013 – 9 –
a
Vacant.
b
This test sequence also applies when, for the 4-poles testing, Sequence III on the 4-poles variant is replaced by
Sequence II or Sequence VI (see Table 9).
c
One sample of maximum current rating only, tested at max kVA rating (I × corresponding U ).
cu e
d
Without verification tests of items c) (undervoltage releases) and d) (shunt releases).
e
Applicable only to 1-pole variant ; not required for 2-poles variants.
f
Vacant.
g
One sample of maximum current rating only, for each test sequence.
h
Vacant.
i
Vacant.
j
Vacant.
k

This test is not required for electronic trip units.
8.3.2.1 General requirements
Add at the end of the existing second paragraph the following new text:
or, where applicable, for the alternative test programmes in Table 9b and Table 9c
(see 8.3.1.4).
Replace the existing fifth paragraph, introduced by Amendment 1, by the following new text:
In the case of one or more construction breaks (see 2.1.2 and 7.1.5) within the frame size,
further samples shall be tested in accordance with Table 9b and/or Table 10 as applicable.
Replace the existing seventeenth paragraph by the following new paragraph:
The tightening torques to be applied to the terminal screws shall be in accordance with the
manufacturer's instructions (see 5.2 e)).
Table 10 – Number of samples for test
Add, between the existing title of the table and the existing table, the following new
paragraph:
Table 10 applies to the test programmes of Table 9. In the case of the alternative test
programmes (see 8.3.1.4), Table 9b and Table 9c are applicable.
The correction concerning I , I and I introduced in the French text of this amendment
cu cs cw
does not apply to the English text.
8.3.2.6.4.2 Tests on one-, two- and three-pole circuit-breakers
Add, after the second dashed item of this existing paragraph, introduced by Amendment 1,
the following new paragraph:
For ratings ≤ 20 A, the manufacturer may specify a larger cross-section, in which case this
cross-section shall be used for all relevant short-circuit tests, and stated in the test report. In
addition, a verification of inverse-time delay releases according to 8.3.3.1.3 b) shall be made
with this cross-section.
8.3.2.6.4.3 Tests on four-pole circuit-breakers
Reformat the first sentence of the existing second paragraph, introduced by Amendment 1, as
follows:

---------------------- Page: 11 ----------------------
– 10 – 60947-2 Amend. 2  IEC:2013
An additional sequence of operations on one or more new samples, in accordance with
Table 10, shall be made on the fourth pole and its adjacent pole for sequences:
– III and IV, or
– IV and V, or
– VI,
as applicable.
8.3.2.6.7 Verification after short-circuit tests
Replace the whole existing item a) by the following new item a) and new note:
a) After the opening operations of the short-circuit making and breaking capacity tests of
8.3.4.1, 8.3.5.2, 8.3.6.4, 8.3.7.1, 8.3.7.6, 8.3.8.3, as applicable, the following conditions shall
be met:
– there shall be no damage to the insulation on conductors used to wire the device;
– the polyethylene sheet shall show no holes visible with normal or corrected vision without
additional magnification. Minuscule holes of less than 0,26 mm diameter can be ignored;
– the case shall not be broken but hairline cracks are acceptable.
NOTE Hairline cracks are a consequence of high gas pressure or thermal stresses due to arcing when
interrupting very high fault currents and are of superficial nature. Consequently, they do not develop through the
entire thickness of the moulded case of the device.
8.3.3.2 Test of dielectric properties
This correction does not apply to the English version.
8.3.3.3.4 Operational performance capability with current
This correction does not apply to the English version.
8.3.3.4 Overload performance
Replace the existing third paragraph of this subclause by the following new paragraph:
The test shall be made at a voltage corresponding to the maximum operational voltage U
e max
assigned by the manufacturer to the circuit-breaker, taking into account the requirement for
recovery voltage of Table 12 (see also 8.3.2.2.3 a) of IEC 60947-1).
Table 12 – Test circuit characteristics for overload performance
This correction does not apply to the English version.
8.3.7 Test sequence V: Performance of integrally fused circuit-breakers
This correction does not apply to the English version.
8.3.8.2 Test of rated short-time withstand current
Add, at the end of the existing subclause, the following new paragraph:
This test does not need to be made on the sample of minimum I specified in Table 10.
n

---------------------- Page: 12 ----------------------
60947-2 Amend. 2  IEC:2013 – 11 –
8.5 Special tests – Damp heat, salt mist, vibration and shock
Add, at the end of the existing subclause, introduced by Amendment 1, before Figure 1, the
two following new paragraphs:
With reference to footnote e) of Table Q.1 of IEC 60947-1, for dry heat test, the circuit-
breaker shall not carry current. Where an under-voltage release is fitted it shall be energised
with rated voltage. The circuit-breaker shall be operated according to 8.4.1 during the last
hour of the test.
With reference to footnote g) of Table Q.1 of IEC 60947-1, during damp heat test, the
functional test shall consist of the mechanical operations of 8.4.1 of this standard. When only
manual operating means are available, this test can be done during the beginning of the
following cold period.

Annex A – Co-ordination under short-circuit conditions between a circuit-
breaker and another short-circuit protective device associated in the same
circuit
Replace, throughout the annex (including Figure A.2), "discrimination" by "selectivity".
Delete "(or I )" in each of the following locations:
cs
– A.3.1, in the first existing paragraph;
– new A.5.1 in the first existing paragraph;
– A.6.2 b) in the second existing paragraph;
– A.6.3 in the sixth and eighth existing paragraphs;
– existing Figure A.2 and Figure A.3.
A.1 Introduction
Replace the existing eighth paragraph by the following new paragraph:
Consideration of selectivity can either be carried out by desk study or by test (see
Clause A.5), whereas the verification of back-up protection normally requires the use of tests
(see Clause A.6).
A.4 Type and characteristics of the associated SCPD
This correction does not apply to the English version.
A.5 Verification of discrimination
Replace the existing title by the following new title and subclause title:
A.5 Verification of selectivity
A.5.1 General
Replace the sentence before the existing dashed list by the following new sentence:
In certain cases, tests at I may be performed on the association, for example:
s

---------------------- Page: 13 ----------------------
– 12 – 60947-2 Amend. 2  IEC:2013
Add, at the end of the existing Clause A.5, the two following new subclauses A.5.2 and A.5.3:
A.5.2 Tests for verification of selectivity between circuit-breakers
An example of the circuit diagram for the tests is shown in Figure A.7.
C1 may be a circuit-breaker in compliance with this standard or another IEC standard.
If C1 is fitted with adjustable over-current opening releases, the operating characteristics shall
be those corresponding to the maximum time and current settings.
If C2 is fitted with adjustable over-current opening releases, the operating characteristics to
be used shall be those corresponding to the minimum time and current settings.
NOTE The settings of releases specified above will allow determination of selectivity for all settings of the
releases.
Tests at other release settings may be made at the discretion of the manufacturer, in which
case the settings of the releases shall be recorded in the test report.
The connecting cables shall be included as specified in 8.3.2.6.4 except the total length of the
cables may be distributed between the supply side and the load side of C1 and C2 as
convenient.
The test shall consist of an O - t - CO operation, the CO operation being made by closing the
downstream device C1.
The test is made at the level of prospective current for which the association of C1 and C2 is
declared by the manufacturer to be selective. This shall not exceed the rated conditional
short-circuit current (see 4.3.6.4 of IEC 60947-1), if applicable, as determined from test A.6.3.
A.5.3 Results to be obtained
Subclause 8.3.4.1.7 of IEC 60947-1 applies (no flashover between poles or to earth).
During each operation, C1 shall trip and C2 shall not trip. If the contacts of C2 separate
momentarily during the operations, the time between the beginning of short-circuit and the
end of C2 contact separation shall be less than or equal to 30 ms. The actual value shall be
stated in the test report.
Following the tests, C1 shall comply with 8.3.5.3 and 8.3.5.4 (dielectric and overload tripping
verifications).
In addition, it shall be verified, by manual operation or other appropriate means, that the
contacts of C2 have not welded.

Figure A.2 – Total discrimination between two circuit-breakers
Replace the existing text "Discrimination in this area must be verified by test" by the following
new text:
Selectivity in this area may be determined by desk study or by test.
as follows:

---------------------- Page: 14 ----------------------
60947-2 Amend. 2  IEC:2013 – 13 –
Selectivity in this area may be
determined by desk study or by test

IEC  1581/01


C = Current-limiting circuit-breaker (L) C = Non-current-limiting circuit-breaker (N)
1 1
(break-time characteristic) (break-time characteristic)
C = Non-current-limiting circuit breaker (N) C = Circuit-breaker with intentional short-time
2
2
(tripping characteristic) delay (STD) (tripping characteristic)
Values of I (or I ) are not shown.
cu cs
Figure A.2 Figure A.3
Total discrimination between two circuit-breakers

---------------------- Page: 15 ----------------------
– 14 – 60947-2 Amend. 2  IEC:2013
Add, at the end of the existing Annex A, the following new Figure A.7:
S = Supply
Ur1, Ur2, Ur3 = Voltage sensors
Ur4, Ur5, Ur6
Ur7, Ur8, Ur9
V = Voltage measuring device
A = Closing device
R = Adjustable resistor
1
N = Neutral of supply
(or artificial neutral)
F = Fusible element
(8.3.4.1.2, item d) of IEC 60947-1)
L = Adjustable reactors
R = Fault current limiting resistor
L
R = Polarising resistors
p
B = Temporary connections for
calibration
I1, I2, I3 = Current sensing devices
T = Earth:– one earthing point only
(load side or supply side)
r = Shunting resistor
(8.3.4.1.2, item b) of IEC 60947-1)
W = 75 cm of cable rated for C2
1
W + W = 75 cm of cable rated for C1
2 3
(see A.5.2)
C1, C2 = Circuit-breakers under test

IEC  146/13


NOTE 1 Adjustable loads L and R1 may be located either on the high voltage side or on the low voltage side of the
supply circuit, the closing device A being located on the low voltage side.
NOTE 2 Ur1, Ur2, Ur3 may, alternatively, be connected between phase and neutral.
NOTE 3 In the case of devices intended for use in a phase-earthed network, F shall be connected to one phase of the
supply.
NOTE 4 In the USA and Canada (see note to 4.3.
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