IEC 61000-3-3:2013

IEC 61000-3-3 ®
Edition 3.0 2013-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection
EC 61000-3-3:2013-05 RLV(en)
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IEC 61000-3-3 ®
Edition 3.0 2013-05
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Electromagnetic compatibility (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker

in public low-voltage supply systems, for equipment with rated current ≤ 16 A

per phase and not subject to conditional connection

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.100.10 ISBN 978-2-8322-0781-9

IEC 61000-3-3 ®
Edition 3.0 2013-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤ 16 A par phase et non
soumis à un raccordement conditionnel

– 2 – 61000-3-3 © IEC:2013
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Assessment of voltage changes, voltage fluctuations and flicker . 10
4.1 Assessment of a relative voltage change, d(t) . 10
4.2 Assessment of the short-term flicker value, P . 10
st
4.2.1 General . 10
4.2.2 Flickermeter . 11
4.2.3 Simulation method . 11
4.2.4 Analytical method . 11
4.2.5 Use of P = 1 curve . 12

st
4.3 Assessment of long-term flicker value, P . 12
lt
5 Limits . 12
6 Test conditions . 13
6.1 General . 13
6.2 Measurement uncertainty . 14
6.3 Test supply voltage . 14
6.4 Reference impedance . 14
6.5 Observation period . 14
6.6 General test conditions . 15
Annex A (normative) Application of limits and type test conditions for specific
equipment . 19
Annex B (normative) Test conditions and procedures for measuring d voltage
max
changes caused by manual switching . 27
Annex C (informative) Determination of steady state voltage and voltage change
characteristics, as defined in IEC 61000-4-15:2010 . 28
Annex D (informative) Input relative voltage fluctuation ∆V/V for P = 1,0 at output
st
[IEC/TR 61000-3-7:2008] . 33
Bibliography . 34

Figure 1 – Reference network for single-phase and three-phase supplies derived from
a three-phase, four-wire supply . 16
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes . 17
st
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics . 17
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics . 18
Figure 5 – Shape factor F for motor-start voltage characteristics having various front
times. 18
Figure C.1 – Evaluation of U (t) . 32
hp
Table 1 – Assessment method . 11
Table A.1 – Test conditions for hotplates . 19
Table A.2 – Electrode parameters . 24
Table A.3 – Frequency factor R related to repetition rate "r" . 25

61000-3-3 © IEC:2013 – 3 –
Table C.1 – Test specification for d – d – t (from Table 12 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table C.2 – Test specification for d – d – t (from Table 13 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table D.1 – Input relative voltage fluctuation ∆V/V for P = 1,0 at output . 33
st
– 4 – 61000-3-3 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

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
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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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.
International Standard IEC 61000-3-3 has been prepared by subcommittee 77A: EMC – Low
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms part 3-3 of IEC 61000 series of standards. It has the status of a product
family standard.
This third edition cancels and replaces the second edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) This edition takes account of the changes made in IEC 61000-4-15:2010.

61000-3-3 © IEC:2013 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
77A/809/FDIS 77A/816/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61000 series, published under the general title Electromagnetic
compatibility (EMC), can be found on the IEC website.
The committee has decided that the contents of this 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.
– 6 – 61000-3-3 © IEC:2013
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 9: Miscellaneous
Each part is further subdivided into sections which are to be published either as International
Standards or as Technical Reports.
These standards and reports will be published in chronological order and numbered
accordingly.
61000-3-3 © IEC:2013 – 7 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

1 Scope
This part of IEC 61000 is concerned with the limitation of voltage fluctuations and flicker
impressed on the public low-voltage system.
It specifies limits of voltage changes which may be produced by an equipment tested under
specified conditions and gives guidance on methods of assessment.
This part of IEC 61000 is applicable to electrical and electronic equipment having an input
current equal to or less than 16 A per phase, intended to be connected to public low-voltage
distribution systems of between 220 V and 250 V line to neutral at 50 Hz, and not subject to
conditional connection.
Equipment which does not comply with the limits of this part of IEC 61000 when tested with
the reference impedance Z of 6.4, and which therefore cannot be declared compliant with
ref
this part, may be retested or evaluated to show conformity with IEC 61000-3-11. Part 3-11 is
applicable to equipment with rated input current ≤ 75 A per phase and subject to conditional
connection.
The tests according to this part are type tests. Particular test conditions are given in Annex A
and the test circuit is shown in Figure 1.
NOTE 1 The limits in this standard relate to the voltage changes experienced by consumers connected at the
interface between the public supply low-voltage network and the equipment user’s installation. Consequently, if the
actual impedance of the supply at the supply terminals of equipment connected within the equipment user’s
installation exceeds the test impedance, it is possible that supply disturbance exceeding the limits could occur.
NOTE 2 The limits in this standard are based mainly on the subjective severity of flicker imposed on the light from
230 V 60 W coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage less
than 220 V line to neutral and/or frequency of 60 Hz, the limits and reference circuit values are under
consideration.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC/TR 60725, Consideration of reference impedances and public supply impedances for use
in determining disturbance characteristics of electrical equipment having a rated current
≤ 75 A per phase
IEC 60974-1, Arc welding equipment – Part 1: Welding power sources
IEC 61000-3-2, Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic
current emissions (equipment input current ≤ 16 A per phase)

– 8 – 61000-3-3 © IEC:2013
IEC 61000-3-11, Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of
voltage changes, voltage fluctuations and flicker in public low-voltage supply systems –
Equipment with rated current ≤ 75 A and subject to conditional connection
IEC 61000-4-15:2010, Electromagnetic compatibility (EMC) – Part 4-15: Testing and
measurement techniques – Flickermeter – Functional and design specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flicker
impression of unsteadiness of visual sensation induced by a light stimulus whose luminance
or spectral distribution fluctuates with time
[SOURCE: IEC 60050-161:1990, 161-08-13]
3.2
voltage change characteristic
d(t)
time function of the relative r.m.s. voltage change evaluated as a single value for each
successive half period between zero-crossings of the source voltage, except during time
intervals in which the voltage is in a steady-state condition for at least 1 s
Note 1 to entry: For detailed information about the evaluation of a voltage change characteristic and the definition
of a steady state condition see Annex C and IEC 61000-4-15:2010.
3.3
d
c
maximum steady state voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
c
3.4
d
max
maximum absolute voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
max
3.5
T
max
maximum time duration during the observation period that the voltage deviation d(t) exceeds
the limit for d
c
Note 1 to entry: During a voltage change characteristic the time duration T is accumulated until a new steady
max
state condition is established.
Note 2 to entry: The T limit evaluation in this standard is generally intended to evaluate the inrush current
max
pattern of the equipment under test. Thus, as soon as a new steady state condition is established, the T
max
evaluation is ended. When a new voltage change occurs that exceeds the limit for d , a new T evaluation is
c max
started. The maximum duration that d(t) exceeds the limit for d for any of the individual T evaluations during the
c max
observation period, is used for the comparison against the T limit, and is reported for the test.
max
3.6
nominal test voltage
U
n
nominal test voltage used to calculate percentages for the various directly measured
parameters
61000-3-3 © IEC:2013 – 9 –
Note 1 to entry: If no steady state condition is achieved during the observation period, U is used for the
n
calculation of d and T .
max max
Note 2 to entry: U is not necessarily equal to the nominal voltage of the public supply.
n
3.7
P
st
short-term flicker severity
Note 1 to entry: If not specified differently, the P evaluation time is 10 minutes. For the purpose of power quality
st
surveys and studies, other time intervals may be used, and have to be defined in the index. For example a 1
minute interval should be written as P
st,1min.
3.8
P
lt
long-term flicker severity
N
P
∑
st,i
i =1
P =
lt
N
where P (i = 1, 2, 3, .) are consecutive readings of the short-term severity P
st
st,i
Note 1 to entry: Unless otherwise specified, P is calculated over discrete T periods. Each time a T period
lt long long
has expired, a new P calculation is started.
lt
3.9
flickermeter
instrument designed to measure any quantity representative of flicker
Note 1 to entry: Measurements are normally P and P and may also include the directly measured parameters
st lt
specified in 3.2 to 3.5.
[SOURCE: IEC 60050-161:1990, 161-08-14]
3.10
flicker impression time
t
f
value with a time dimension which describes the flicker impression of a voltage change
characteristic
3.11
shape factor
F
value derived from the type of voltage fluctuation, such as a step, double step, or ramp
pattern
Note 1 to entry: The shape factor is mainly needed when the analytical method is used to calculate P .
st
3.12
interface point
interface between a public supply network and a user’s installation
3.13
conditional connection
connection of equipment requiring the user’s supply at the interface point to have an
impedance lower than the reference impedance Z in order that the equipment emissions
ref
comply with the limits in this part
Note 1 to entry: Meeting the voltage change limits may not be the only condition for connection; emission limits
for other phenomena such as harmonics, may also have to be satisfied.

– 10 – 61000-3-3 © IEC:2013
4 Assessment of voltage changes, voltage fluctuations and flicker
4.1 Assessment of a relative voltage change, d(t)
The basis for flicker evaluation is the voltage change characteristic at the terminals of the
(t) of any two successive values of the
equipment under test, that is the difference ∆ U
hp
phase-to-neutral voltages U (t ) and U (t ):
hp 1 hp 2
∆ U (t) = U (t ) – U (t ) (1)
hp hp 1 hp 2
NOTE 1 See Annex C for relevant definitions that are taken from IEC 61000-4-15:2010.
The r.m.s. values U (t ), U (t ) of the voltage shall be measured or calculated. When
hp 1 hp 2
deducing r.m.s. values from oscillographic waveforms, account should be taken of any
waveform distortion that may be present.
The voltage change at the EUT terminals, ∆U, is due to the change of the voltage drop across
the complex reference impedance Z, caused by the complex fundamental input current
change, ∆I, of the equipment under test. ∆I and ∆I are the active and reactive parts
p q
respectively of the current change, ∆I.
∆I = ∆I – j∆I = I(t ) – I(t ) (2)
p q
1 2
NOTE 2 I is positive for lagging currents and negative for leading currents.
q
NOTE 3 If the harmonic distortion of the currents I(t ) and I(t ) is less than 10 %, the total r.m.s. value can be
1 2
applied instead of the r.m.s. values of their fundamental currents, taking account of the phase angles of the
fundamental currents.
NOTE 4 For single-phase and symmetrical three-phase equipment the voltage change can be, provided X is
positive (inductive), approximated to:
∆U = ∆I R + ∆I X (3)
hp p q
where ∆I and ∆I are the active and reactive parts respectively of the current change ∆I and R and X are the
p q
elements of the complex reference impedance Z (see Figure 1).
The relative voltage change is given by:
d = ∆U /U (4)
hp n
The d evaluation ends as soon as a new steady state condition is established, or at the
max,i
end of the observation period. The polarity of change(s) may be indicated as follows: if the
maximum voltage deviation is observed during a reduction in voltage with respect to the
previous d the resulting d value is positive; if the maximum voltage deviation is
end,i max,i
the resulting d
observed during a voltage increase with respect to the previous d
end,i max,i
value is negative.
4.2 Assessment of the short-term flicker value, P
st
4.2.1 General
Table 1 shows alternative methods for evaluating P , due to voltage fluctuations of different

st
types; in all cases direct measurement (with a flickermeter) is acceptable:

61000-3-3 © IEC:2013 – 11 –
Table 1 – Assessment method
Types of voltage fluctuations Method for evaluating P
st
All voltage fluctuations (on-line evaluation) Flickermeter
All voltage fluctuations where U(t) is known Simulation
Voltage change characteristics according to Figures 3 Analytical
to 5 with an occurrence rate less than 1 per second
Rectangular voltage change at equal intervals Use of the P = 1 curve of Figure 2

st
4.2.2 Flickermeter
All types of voltage fluctuations may be assessed by direct measurement using a flickermeter
which complies with the specification given in IEC 61000-4-15:2010, and is connected as
described in this standard. This is the reference method for application of the limits.
4.2.3 Simulation method
In the case where the relative voltage change characteristic d(t) is known, P can be

st
evaluated using a computer simulation.
4.2.4 Analytical method
4.2.4.1 General
For voltage change characteristics of the types shown in Figures 3, 4 and 5, the P value can

st
be evaluated by an analytical method using Equations (5) and (6).
NOTE 1 The value of P obtained using this method is expected to be within ± 10 % of the result which would be
st
obtained by direct measurement (reference method).
NOTE 2 This method is not used if the time duration between the end of one voltage change and the start of the
next is less than 1 s.
4.2.4.2 Description of the analytical method
Each relative voltage change characteristic shall be expressed by a flicker impression time, t ,
f
in seconds:
3,2
t = 2,3 (Fd ) (5)
f max
– the maximum relative voltage change d is expressed as a percentage of the nominal

max
voltage U ;
n
– the shape factor, F, is associated with the shape of the voltage change characteristic (see
4.2.4.3).
The sum of the flicker impression times, Σt , of all evaluation periods within a total interval of
f
the length T , in seconds, is the basis for the P evaluation. If the total time interval T is

p st p
chosen according to 6.5, it is an "observation period", and:
1/3,2
P = (Σt /T ) (6)
st f p
4.2.4.3 Shape factor
The shape factor, F, converts a relative voltage change characteristic d(t) into a flicker
equivalent relative step voltage change (Fd ).
max
– 12 – 61000-3-3 © IEC:2013
NOTE 1 The shape factor, F, is equal to 1,0 for step voltage changes.
NOTE 2 The relative voltage change characteristic can be measured directly (see Figure 1) or calculated from the
r.m.s. current of the equipment under test (see Equations (1) to (4)).
The relative voltage change characteristic shall be obtained from a time progression of U (t)
hp
(see Figure C.1).
The shape factor may be deduced from Figures 3, 4 and 5, provided that the relative voltage
change characteristic matches a characteristic shown in these figures. If the characteristics
match, proceed as follows:
– find the maximum relative voltage change d ; and
max
– find the time T (in ms) appropriate to the voltage change characteristic as shown in
Figures 3, 4 and 5 and, using this value, obtain the required shape factor, F.
NOTE 3 Extrapolation outside the range of the figures would lead to unacceptable errors.
4.2.5 Use of P = 1 curve
st
In the case of rectangular voltage changes of the same amplitude d separated by equal time
intervals, the curve of Figure 2 may be used to deduce the amplitude corresponding to P = 1

st
for a particular rate of repetition; this amplitude is called d . The P value corresponding to

lim st
the voltage change d is then given by P = d/d .

st lim
4.3 Assessment of long-term flicker value, P
lt
The long-term flicker value P shall be applied with the value of N = 12 (see 6.5).

lt
It is generally necessary to assess the value of P for equipment which is normally operated

lt
for more than 30 min at a time.
5 Limits
The limits shall be applicable to voltage fluctuations and flicker at the supply terminals of the
equipment under test, measured or calculated according to Clause 4 under test conditions
described in Clause 6 and Annex A. Tests made to prove compliance with the limits are
considered to be type tests.
The following limits apply:
• the value of P shall not be greater than 1,0;
st
• the value of P shall not be greater than 0,65;
lt
• T , the accumulated time value of d(t) with a deviation exceeding 3,3 % during a single
max
voltage change at the EUT terminals, shall not exceed 500 ms;
• the maximum relative steady-state voltage change, d , shall not exceed 3,3 %;
c
• the maximum relative voltage change d , shall not exceed:
max
a) 4 % without additional conditions;
b) 6 % for equipment which is:
– switched manually, or
– switched automatically more frequently than twice per day, and also has either a
delayed restart (the delay being not less than a few tens of seconds), or manual
restart, after a power supply interruption.
NOTE The cycling frequency is further limited by the P and P limits. For example: a d of 6 % producing a
st lt max
rectangular voltage change characteristic twice per hour gives a P of about 0,65.
lt
61000-3-3 © IEC:2013 – 13 –
c) 7 % for equipment which is:
– attended whilst in use (for example: hair dryers, vacuum cleaners, kitchen
equipment such as mixers, garden equipment such as lawn mowers, portable tools
such as electric drills), or
– switched on automatically, or is intended to be switched on manually, no more than
twice per day, and also has either a delayed restart (the delay being not less than a
few tens of seconds) or manual restart, after a power supply interruption.
In the case of equipment having several separately controlled circuits in accordance with 6.6,
limits b) and c) shall apply only if there is delayed or manual restart after a power supply
interruption; for all equipment with automatic switching which is energized immediately on
restoration of supply after a power supply interruption, limits a) shall apply; for all equipment
with manual switching, limits b) or c) shall apply depending on the rate of switching.
P and P requirements shall not be applied to voltage changes caused by manual switching.

st lt
The limits shall not be applied to voltage changes associated with emergency switching or
emergency interruptions.
6 Test conditions
6.1 General
Tests need not be made on equipment which is unlikely to produce significant voltage
fluctuations or flicker. Where it is considered necessary to conduct tests, the equipment shall
comply with all limits in Clause 5 for the tests described in Annex A unless there are specific
exclusions for a particular type of equipment.
It may be necessary to determine, by examination of the circuit diagram and specification of
the equipment and by a short functional test, whether significant voltage fluctuations are likely
to be produced.
For voltage changes caused by manual switching, equipment is deemed to comply without
further testing if the maximum r.m.s. input current (including inrush current) evaluated over
each 10 ms half-period between zero-crossings does not exceed 20 A, and the supply current
after inrush is within a variation band of 1,5 A.
If measurement methods are used, the maximum relative voltage change d caused by

max
manual switching shall be measured in accordance with Annex B.
Tests to prove the compliance of the equipment with the limits shall be made using the test
circuit in Figure 1.
The test circuit consists of:
• the test supply voltage (see 6.3);
• the reference impedance (see 6.4);
• the equipment under test (see Annex A);
• if necessary, a flickermeter (see IEC 61000-4-15:2010).
The relative voltage change d (t) may be measured directly or derived from the r.m.s. current
hp
as described in 4.1. To determine the P value of the equipment under test, one of the

st
methods described in 4.2 shall be used. In case of doubt, the P shall be measured using

st
the reference method with a flickermeter.

– 14 – 61000-3-3 © IEC:2013
NOTE If balanced multiphase equipment is tested, it is acceptable to measure only one of the three line-to-neutral
voltages.
6.2 Measurement uncertainty
The magnitude of the current shall be measured with an accuracy of ± (1 % + 10 mA) or
better, where the 1 % is referred to the measured value. If, instead of active and reactive
current, the phase angle is used, its error shall not exceed ± 2°.
The directly measured parameters (see Clauses 3 and 4) shall be determined with a total
uncertainty better than ± 8 % of the limit value, or ± 8 % of the measured value, whichever is
higher. The total impedance of the circuit, excluding the appliance under test, but including
the internal impedance of the supply source, shall be equal to the reference impedance. The
stability and tolerance of this total impedance shall be adequate to ensure that the overall
uncertainty of ± 8 % is achieved during the whole assessment procedure.
If the source impedance is not well defined, for example where the source impedance is
subject to unpredictable variations, an impedance having resistance and inductance equal to
the reference impedance may be connected between the supply and the terminals of the
equipment under test. Measurements can then be made of the voltages at the source side of
the reference impedance and at the equipment terminals. In that case, the maximum relative
voltage change, d , measured at the supply terminals shall be less than 20 % of the
max
maximum value d measured at the equipment terminals.

max
NOTE The above method using a voltage source with undefined impedance is not used where the measured
values are close to the limits.
6.3 Test supply voltage
The test supply voltage (open-circuit voltage) shall be the rated voltage of the equipment. If a
voltage range is stipulated for the equipment, the test voltage shall be 230 V single-phase or
400 V three-phase. The test voltage shall be maintained within ± 2 % of the nominal value.
The frequency shall be 50 Hz ± 0,25 Hz.
The percentage total harmonic distortion of the supply voltage shall be less than 3 %.
Fluctuations of the test supply voltage during a test may be neglected if the P value,
st
produced from these fluctuations, is less than 0,4. If the measurements are made directly
using the mains supply, this condition shall be verified before and after each test. If
measurements are made using a controlled power source, this condition shall be verified
during calibration of the power source.
NOTE Frequency deviations can cause the measured P and P values to increase. Also, when testing a flicker
st lt
meter response according to Tables 1b and 2b in IEC 61000-4-15: 2010, the 50 Hz frequency is preferably
controlled to within ± 0,25 Hz.
6.4 Reference impedance
For equipment under test the reference impedance, Z according to IEC/TR 60725, is a
,
ref
conventional impedance used in the calculation and measurement of the directly measured
parameters, and the P and P values.

st lt
The impedance values of the various elements are given in Figure 1.
6.5 Observation period
The observation period, T , for the assessment of flicker values by flicker measurement,
p
flicker simulation, or analytical method shall be:
• for P , T = 10 min;
st p
61000-3-3 © IEC:2013 – 15 –
• for P , T = 2 h.
lt p
The observation period shall include that part of the whole operation cycle in which the
equipment under test produces the most unfavourable sequence of voltage changes.
For the assessment of P , the cycle of operation shall be repeated continuously, unless

st
stated otherwise in Annex A. The minimum time to restart the equipment shall be included in
this observation period when testing equipment that stops automatically at the end of a cycle
of operation which lasts for less than the observation period.
For P assessment, the cycle of operation shall not be repeated, unless stated otherwise in

lt
Annex A, when testing equipment with a cycle of operation of less than 2 h and which is not
normally used continuously.
NOTE For example, in the case of equipment with a cycle of operation lasting 45 min, five consecutive P values

st
are measured during a total period of 50 min, and the remaining seven P values in the 2 h observation period are

st
deemed to be zero.
6.6 General test conditions
The test conditions for the measurement of voltage fluctuations and flicker are given below.
For equipment not mentioned in Annex A, controls or automatic programs shall be set to
produce the most unfavourable sequence of voltage changes, using only those combinations
of controls and programmes which are mentioned by the manufacturer in the instruction
manual, or are otherwise likely to be used.
The equipment shall be tested in the condition in which it is supplied by the manufacturer.
Preliminary operation of motor drives may be needed before the tests to ensure that results
corresponding to those of normal use are obtained.
NOTE Operating conditions include mechanical and/or electrical loading conditions.
For motors, locked-rotor measurements may be used to determine the largest r.m.s. voltage
change, d , occurring during motor starting.
max
For equipment having several separately controlled circuits, the following conditions apply:
• each circuit shall be considered as a single item of equipment if it is intended to be used
independently, provided that the controls are not designed to switch at the same instant;
• if the controls of separate circuits are designed to switch simultaneously, the group of
circuits so controlled are considered as a single item of equipment.
For control systems regulating part of a load only, the voltage fluctuations produced by each
variable part of the load alone shall be considered.
Detailed type test conditions for some equipment are given in Annex A.

– 16 – 61000-3-3 © IEC:2013
S
R jX
A A
L1
G
R jX
A A L2
G
EUT
R jX
A A L3
G
R jX
N N N
M
IEC  945/13
Key
G voltage source in accordance with 6.3.
EUT equipment under test
M measuring equipment
S supply source consisting of the supply voltage generator G and reference impedance Z with the elements:
R = 0,24 Ω; jX = 0,15 Ω at 50 Hz;

A A
= 0,16 Ω; jX = 0,10 Ω at 50 Hz.
R
N N
NOTE 1 The elements include the actual generator impedance.
NOTE 2 When the source impedance is not well defined, see 6.2.
NOTE 3 In general, three-phase loads are balanced, and R and X can be neglected, as there is no current in

N N
the neutral wire.
Figure 1 – Reference network for single-phase and three-phase supplies
derived from a three-phase, four-wire supply

61000-3-3 © IEC:2013 – 17 –
See Clause 5 for limits in this area
0,3
0,1
–1 0 1 2 3 4
10 10 10 10 10 10
Number of voltage changes per minute
IEC  946/13
NOTE 1 1 200 voltage changes per minute give a 10 Hz flicker.
NOTE 2 Annex D includes a numerical table corresponding to Figure 2, taken from IEC/TR 61000-3-7:2008.
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes
st
1,0
0,8
T
0,6
d /2
max
≅
d /2 F × d
max max
0,4
T
0,2
d
max
F × d
≅
max
1 2 3
2 3 5 2 3 5
10 10 10
T  (ms)
IEC  947/13
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics

d  (%)
F
– 18 – 61000-3-3 © IEC:2013
1,4
1,2
1,0
0,8
0,6
T/2 T/2
≅
F × d
max
0,4
d
max
0,2 d
max ≅ F × d
max
T
1 2 3
2 3 5 2 3 5
10 10 10
T  (ms)
IEC  948/13
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics

1,2
10, 20
1,0
0,8
T (ms)
f
0,6
0,4
T 400
t Tail time
d
max
F × d
≅ max
0,2
T
Front time
f
1 2 3
2 3 5 2 3 5
10 10 10
T  (ms)
t
IEC  949/13
NOTE T = t – t , T = t – t (see Figure C.1).

t 3 2 f 2 1
Figure 5 – Shape factor F for motor-start voltage characteristics
having various front times
F
F
61000-3-3 © IEC:2013 – 19 –
Annex A
(normative)
Application of limits and type test conditions
for specific equipment
A.1 Test conditions for cookers
A.1.1 General
For cookers designed for use in domestic premises, the evaluation of P shall not be required.

lt
shall be performed at steady-state temperature conditions, unless stated
The tests of P
st
otherwise.
Each heater shall be tested separately as follows.
A.1.2 Hotplates
Hotplates shall be tested using standard saucepans with diameter, height and water quantity
as follows:
Table A.1 – Test conditions for hotplates
Diameter of the hotplate Height of the pot Quantity of water
mm mm g
145 about 140
1 000 ± 50
180 about 140 1 500 ± 50
220 about 120
2 000 ± 50
Losses by evaporation shall be compensated for during the time of measurement.
In all of the following tests the hotplate shall comply with the limits given in Clause 5.
a) Boiling temperature range: set the control to the position where the water just boils. The
test is made five times and the mean value of the test results calculated.
b) Frying temperature range: fill the pot, without a lid, with silicone oil to 1,5 times the
quantity of water shown in Table A.1. Set the control to a temperature of 180 °C measured
by a thermocouple in the geometric centre of the oil.
c) Total range of power settings: the total power range shall be checked continuously during
a 10 min observation period. If control switches have discrete stages, test all stages up to
a maximum of 20 stages. If there are no discrete stages, divide the total range into
10 equally spaced steps. The measurements shall then be made starting at the highest
power stage.
A.1.3 Baking ovens
The oven shall be tested empty with the door closed. Adjust the control so that a
thermocouple fixed in the geometric centre measures a mean temperature of 220 °C for
conventional ovens and 200 °C for hot air ovens.
...

IEC 61000-3-3 ®
Edition 3.0 2013-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤ 16 A par phase et non
soumis à un raccordement conditionnel

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IEC 61000-3-3 ®
Edition 3.0 2013-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electromagnetic compatibility (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker

in public low-voltage supply systems, for equipment with rated current ≤ 16 A

per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –

Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de

tension et du papillotement dans les réseaux publics d'alimentation basse

tension, pour les matériels ayant un courant assigné ≤ 16 A par phase et non

soumis à un raccordement conditionnel

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 33.100.10 ISBN 978-2-83220-781-9

– 2 – 61000-3-3 © IEC:2013
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Assessment of voltage changes, voltage fluctuations and flicker . 10
4.1 Assessment of a relative voltage change, d(t) . 10
4.2 Assessment of the short-term flicker value, P . 10
st
4.2.1 General . 10
4.2.2 Flickermeter . 11
4.2.3 Simulation method . 11
4.2.4 Analytical method . 11
4.2.5 Use of P = 1 curve . 12

st
4.3 Assessment of long-term flicker value, P . 12
lt
5 Limits . 12
6 Test conditions . 13
6.1 General . 13
6.2 Measurement uncertainty . 14
6.3 Test supply voltage . 14
6.4 Reference impedance . 14
6.5 Observation period . 14
6.6 General test conditions . 15
Annex A (normative) Application of limits and type test conditions for specific
equipment . 19
Annex B (normative) Test conditions and procedures for measuring d voltage
max
changes caused by manual switching . 27
Annex C (informative) Determination of steady state voltage and voltage change
characteristics, as defined in IEC 61000-4-15:2010 . 28
Annex D (informative) Input relative voltage fluctuation ∆V/V for P = 1,0 at output
st
[IEC/TR 61000-3-7:2008] . 33
Bibliography . 34

Figure 1 – Reference network for single-phase and three-phase supplies derived from
a three-phase, four-wire supply . 16
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes . 17
st
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics . 17
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics . 18
Figure 5 – Shape factor F for motor-start voltage characteristics having various front
times. 18
Figure C.1 – Evaluation of U (t) . 32
hp
Table 1 – Assessment method . 11
Table A.1 – Test conditions for hotplates . 19
Table A.2 – Electrode parameters . 24
Table A.3 – Frequency factor R related to repetition rate "r" . 25

61000-3-3 © IEC:2013 – 3 –
Table C.1 – Test specification for d – d – t (from Table 12 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table C.2 – Test specification for d – d – t (from Table 13 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table D.1 – Input relative voltage fluctuation ∆V/V for P = 1,0 at output . 33
st
– 4 – 61000-3-3 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

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.
International Standard IEC 61000-3-3 has been prepared by subcommittee 77A: EMC – Low
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms part 3-3 of IEC 61000 series of standards. It has the status of a product
family standard.
This third edition cancels and replaces the second edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) This edition takes account of the changes made in IEC 61000-4-15:2010.

61000-3-3 © IEC:2013 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
77A/809/FDIS 77A/816/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61000 series, published under the general title Electromagnetic
compatibility (EMC), can be found on the IEC website.
The committee has decided that the contents of this 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.
– 6 – 61000-3-3 © IEC:2013
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 9: Miscellaneous
Each part is further subdivided into sections which are to be published either as International
Standards or as Technical Reports.
These standards and reports will be published in chronological order and numbered
accordingly.
61000-3-3 © IEC:2013 – 7 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

1 Scope
This part of IEC 61000 is concerned with the limitation of voltage fluctuations and flicker
impressed on the public low-voltage system.
It specifies limits of voltage changes which may be produced by an equipment tested under
specified conditions and gives guidance on methods of assessment.
This part of IEC 61000 is applicable to electrical and electronic equipment having an input
current equal to or less than 16 A per phase, intended to be connected to public low-voltage
distribution systems of between 220 V and 250 V line to neutral at 50 Hz, and not subject to
conditional connection.
Equipment which does not comply with the limits of this part of IEC 61000 when tested with
the reference impedance Z of 6.4, and which therefore cannot be declared compliant with
ref
this part, may be retested or evaluated to show conformity with IEC 61000-3-11. Part 3-11 is
applicable to equipment with rated input current ≤ 75 A per phase and subject to conditional
connection.
The tests according to this part are type tests. Particular test conditions are given in Annex A
and the test circuit is shown in Figure 1.
NOTE 1 The limits in this standard relate to the voltage changes experienced by consumers connected at the
interface between the public supply low-voltage network and the equipment user’s installation. Consequently, if the
actual impedance of the supply at the supply terminals of equipment connected within the equipment user’s
installation exceeds the test impedance, it is possible that supply disturbance exceeding the limits could occur.
NOTE 2 The limits in this standard are based mainly on the subjective severity of flicker imposed on the light from
230 V 60 W coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage less
than 220 V line to neutral and/or frequency of 60 Hz, the limits and reference circuit values are under
consideration.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC/TR 60725, Consideration of reference impedances and public supply impedances for use
in determining disturbance characteristics of electrical equipment having a rated current
≤ 75 A per phase
IEC 60974-1, Arc welding equipment – Part 1: Welding power sources
IEC 61000-3-2, Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic
current emissions (equipment input current ≤ 16 A per phase)

– 8 – 61000-3-3 © IEC:2013
IEC 61000-3-11, Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of
voltage changes, voltage fluctuations and flicker in public low-voltage supply systems –
Equipment with rated current ≤ 75 A and subject to conditional connection
IEC 61000-4-15:2010, Electromagnetic compatibility (EMC) – Part 4-15: Testing and
measurement techniques – Flickermeter – Functional and design specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flicker
impression of unsteadiness of visual sensation induced by a light stimulus whose luminance
or spectral distribution fluctuates with time
[SOURCE: IEC 60050-161:1990, 161-08-13]
3.2
voltage change characteristic
d(t)
time function of the relative r.m.s. voltage change evaluated as a single value for each
successive half period between zero-crossings of the source voltage, except during time
intervals in which the voltage is in a steady-state condition for at least 1 s
Note 1 to entry: For detailed information about the evaluation of a voltage change characteristic and the definition
of a steady state condition see Annex C and IEC 61000-4-15:2010.
3.3
d
c
maximum steady state voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
c
3.4
d
max
maximum absolute voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
max
3.5
T
max
maximum time duration during the observation period that the voltage deviation d(t) exceeds
the limit for d
c
Note 1 to entry: During a voltage change characteristic the time duration T is accumulated until a new steady
max
state condition is established.
Note 2 to entry: The T limit evaluation in this standard is generally intended to evaluate the inrush current
max
pattern of the equipment under test. Thus, as soon as a new steady state condition is established, the T
max
evaluation is ended. When a new voltage change occurs that exceeds the limit for d , a new T evaluation is
c max
started. The maximum duration that d(t) exceeds the limit for d for any of the individual T evaluations during the
c max
observation period, is used for the comparison against the T limit, and is reported for the test.
max
3.6
nominal test voltage
U
n
nominal test voltage used to calculate percentages for the various directly measured
parameters
61000-3-3 © IEC:2013 – 9 –
Note 1 to entry: If no steady state condition is achieved during the observation period, U is used for the
n
calculation of d and T .
max max
Note 2 to entry: U is not necessarily equal to the nominal voltage of the public supply.
n
3.7
P
st
short-term flicker severity
Note 1 to entry: If not specified differently, the P evaluation time is 10 minutes. For the purpose of power quality
st
surveys and studies, other time intervals may be used, and have to be defined in the index. For example a 1
minute interval should be written as P
st,1min.
3.8
P
lt
long-term flicker severity
N
P
∑
st,i
i =1
P =
lt
N
where P (i = 1, 2, 3, .) are consecutive readings of the short-term severity P
st
st,i
Note 1 to entry: Unless otherwise specified, P is calculated over discrete T periods. Each time a T period
lt long long
has expired, a new P calculation is started.
lt
3.9
flickermeter
instrument designed to measure any quantity representative of flicker
Note 1 to entry: Measurements are normally P and P and may also include the directly measured parameters
st lt
specified in 3.2 to 3.5.
[SOURCE: IEC 60050-161:1990, 161-08-14]
3.10
flicker impression time
t
f
value with a time dimension which describes the flicker impression of a voltage change
characteristic
3.11
shape factor
F
value derived from the type of voltage fluctuation, such as a step, double step, or ramp
pattern
Note 1 to entry: The shape factor is mainly needed when the analytical method is used to calculate P .
st
3.12
interface point
interface between a public supply network and a user’s installation
3.13
conditional connection
connection of equipment requiring the user’s supply at the interface point to have an
impedance lower than the reference impedance Z in order that the equipment emissions
ref
comply with the limits in this part
Note 1 to entry: Meeting the voltage change limits may not be the only condition for connection; emission limits
for other phenomena such as harmonics, may also have to be satisfied.

– 10 – 61000-3-3 © IEC:2013
4 Assessment of voltage changes, voltage fluctuations and flicker
4.1 Assessment of a relative voltage change, d(t)
The basis for flicker evaluation is the voltage change characteristic at the terminals of the
(t) of any two successive values of the
equipment under test, that is the difference ∆ U
hp
phase-to-neutral voltages U (t ) and U (t ):
hp 1 hp 2
∆ U (t) = U (t ) – U (t ) (1)
hp hp 1 hp 2
NOTE 1 See Annex C for relevant definitions that are taken from IEC 61000-4-15:2010.
The r.m.s. values U (t ), U (t ) of the voltage shall be measured or calculated. When
hp 1 hp 2
deducing r.m.s. values from oscillographic waveforms, account should be taken of any
waveform distortion that may be present.
The voltage change at the EUT terminals, ∆U, is due to the change of the voltage drop across
the complex reference impedance Z, caused by the complex fundamental input current
change, ∆I, of the equipment under test. ∆I and ∆I are the active and reactive parts
p q
respectively of the current change, ∆I.
∆I = ∆I – j∆I = I(t ) – I(t ) (2)
p q
1 2
NOTE 2 I is positive for lagging currents and negative for leading currents.
q
NOTE 3 If the harmonic distortion of the currents I(t ) and I(t ) is less than 10 %, the total r.m.s. value can be
1 2
applied instead of the r.m.s. values of their fundamental currents, taking account of the phase angles of the
fundamental currents.
NOTE 4 For single-phase and symmetrical three-phase equipment the voltage change can be, provided X is
positive (inductive), approximated to:
∆U = ∆I R + ∆I X (3)
hp p q
where ∆I and ∆I are the active and reactive parts respectively of the current change ∆I and R and X are the
p q
elements of the complex reference impedance Z (see Figure 1).
The relative voltage change is given by:
d = ∆U /U (4)
hp n
The d evaluation ends as soon as a new steady state condition is established, or at the
max,i
end of the observation period. The polarity of change(s) may be indicated as follows: if the
maximum voltage deviation is observed during a reduction in voltage with respect to the
previous d the resulting d value is positive; if the maximum voltage deviation is
end,i max,i
the resulting d
observed during a voltage increase with respect to the previous d
end,i max,i
value is negative.
4.2 Assessment of the short-term flicker value, P
st
4.2.1 General
Table 1 shows alternative methods for evaluating P , due to voltage fluctuations of different

st
types; in all cases direct measurement (with a flickermeter) is acceptable:

61000-3-3 © IEC:2013 – 11 –
Table 1 – Assessment method
Types of voltage fluctuations Method for evaluating P
st
All voltage fluctuations (on-line evaluation) Flickermeter
All voltage fluctuations where U(t) is known Simulation
Voltage change characteristics according to Figures 3 Analytical
to 5 with an occurrence rate less than 1 per second
Rectangular voltage change at equal intervals Use of the P = 1 curve of Figure 2

st
4.2.2 Flickermeter
All types of voltage fluctuations may be assessed by direct measurement using a flickermeter
which complies with the specification given in IEC 61000-4-15:2010, and is connected as
described in this standard. This is the reference method for application of the limits.
4.2.3 Simulation method
In the case where the relative voltage change characteristic d(t) is known, P can be

st
evaluated using a computer simulation.
4.2.4 Analytical method
4.2.4.1 General
For voltage change characteristics of the types shown in Figures 3, 4 and 5, the P value can

st
be evaluated by an analytical method using Equations (5) and (6).
NOTE 1 The value of P obtained using this method is expected to be within ± 10 % of the result which would be
st
obtained by direct measurement (reference method).
NOTE 2 This method is not used if the time duration between the end of one voltage change and the start of the
next is less than 1 s.
4.2.4.2 Description of the analytical method
Each relative voltage change characteristic shall be expressed by a flicker impression time, t ,
f
in seconds:
3,2
t = 2,3 (Fd ) (5)
f max
– the maximum relative voltage change d is expressed as a percentage of the nominal

max
voltage U ;
n
– the shape factor, F, is associated with the shape of the voltage change characteristic (see
4.2.4.3).
The sum of the flicker impression times, Σt , of all evaluation periods within a total interval of
f
the length T , in seconds, is the basis for the P evaluation. If the total time interval T is

p st p
chosen according to 6.5, it is an "observation period", and:
1/3,2
P = (Σt /T ) (6)
st f p
4.2.4.3 Shape factor
The shape factor, F, converts a relative voltage change characteristic d(t) into a flicker
equivalent relative step voltage change (Fd ).
max
– 12 – 61000-3-3 © IEC:2013
NOTE 1 The shape factor, F, is equal to 1,0 for step voltage changes.
NOTE 2 The relative voltage change characteristic can be measured directly (see Figure 1) or calculated from the
r.m.s. current of the equipment under test (see Equations (1) to (4)).
The relative voltage change characteristic shall be obtained from a time progression of U (t)
hp
(see Figure C.1).
The shape factor may be deduced from Figures 3, 4 and 5, provided that the relative voltage
change characteristic matches a characteristic shown in these figures. If the characteristics
match, proceed as follows:
– find the maximum relative voltage change d ; and
max
– find the time T (in ms) appropriate to the voltage change characteristic as shown in
Figures 3, 4 and 5 and, using this value, obtain the required shape factor, F.
NOTE 3 Extrapolation outside the range of the figures would lead to unacceptable errors.
4.2.5 Use of P = 1 curve
st
In the case of rectangular voltage changes of the same amplitude d separated by equal time
intervals, the curve of Figure 2 may be used to deduce the amplitude corresponding to P = 1

st
for a particular rate of repetition; this amplitude is called d . The P value corresponding to

lim st
the voltage change d is then given by P = d/d .

st lim
4.3 Assessment of long-term flicker value, P
lt
The long-term flicker value P shall be applied with the value of N = 12 (see 6.5).

lt
It is generally necessary to assess the value of P for equipment which is normally operated

lt
for more than 30 min at a time.
5 Limits
The limits shall be applicable to voltage fluctuations and flicker at the supply terminals of the
equipment under test, measured or calculated according to Clause 4 under test conditions
described in Clause 6 and Annex A. Tests made to prove compliance with the limits are
considered to be type tests.
The following limits apply:
• the value of P shall not be greater than 1,0;
st
• the value of P shall not be greater than 0,65;
lt
• T , the accumulated time value of d(t) with a deviation exceeding 3,3 % during a single
max
voltage change at the EUT terminals, shall not exceed 500 ms;
• the maximum relative steady-state voltage change, d , shall not exceed 3,3 %;
c
• the maximum relative voltage change d , shall not exceed:
max
a) 4 % without additional conditions;
b) 6 % for equipment which is:
– switched manually, or
– switched automatically more frequently than twice per day, and also has either a
delayed restart (the delay being not less than a few tens of seconds), or manual
restart, after a power supply interruption.
NOTE The cycling frequency is further limited by the P and P limits. For example: a d of 6 % producing a
st lt max
rectangular voltage change characteristic twice per hour gives a P of about 0,65.
lt
61000-3-3 © IEC:2013 – 13 –
c) 7 % for equipment which is:
– attended whilst in use (for example: hair dryers, vacuum cleaners, kitchen
equipment such as mixers, garden equipment such as lawn mowers, portable tools
such as electric drills), or
– switched on automatically, or is intended to be switched on manually, no more than
twice per day, and also has either a delayed restart (the delay being not less than a
few tens of seconds) or manual restart, after a power supply interruption.
In the case of equipment having several separately controlled circuits in accordance with 6.6,
limits b) and c) shall apply only if there is delayed or manual restart after a power supply
interruption; for all equipment with automatic switching which is energized immediately on
restoration of supply after a power supply interruption, limits a) shall apply; for all equipment
with manual switching, limits b) or c) shall apply depending on the rate of switching.
P and P requirements shall not be applied to voltage changes caused by manual switching.

st lt
The limits shall not be applied to voltage changes associated with emergency switching or
emergency interruptions.
6 Test conditions
6.1 General
Tests need not be made on equipment which is unlikely to produce significant voltage
fluctuations or flicker. Where it is considered necessary to conduct tests, the equipment shall
comply with all limits in Clause 5 for the tests described in Annex A unless there are specific
exclusions for a particular type of equipment.
It may be necessary to determine, by examination of the circuit diagram and specification of
the equipment and by a short functional test, whether significant voltage fluctuations are likely
to be produced.
For voltage changes caused by manual switching, equipment is deemed to comply without
further testing if the maximum r.m.s. input current (including inrush current) evaluated over
each 10 ms half-period between zero-crossings does not exceed 20 A, and the supply current
after inrush is within a variation band of 1,5 A.
If measurement methods are used, the maximum relative voltage change d caused by

max
manual switching shall be measured in accordance with Annex B.
Tests to prove the compliance of the equipment with the limits shall be made using the test
circuit in Figure 1.
The test circuit consists of:
• the test supply voltage (see 6.3);
• the reference impedance (see 6.4);
• the equipment under test (see Annex A);
• if necessary, a flickermeter (see IEC 61000-4-15:2010).
The relative voltage change d (t) may be measured directly or derived from the r.m.s. current
hp
as described in 4.1. To determine the P value of the equipment under test, one of the

st
methods described in 4.2 shall be used. In case of doubt, the P shall be measured using

st
the reference method with a flickermeter.

– 14 – 61000-3-3 © IEC:2013
NOTE If balanced multiphase equipment is tested, it is acceptable to measure only one of the three line-to-neutral
voltages.
6.2 Measurement uncertainty
The magnitude of the current shall be measured with an accuracy of ± (1 % + 10 mA) or
better, where the 1 % is referred to the measured value. If, instead of active and reactive
current, the phase angle is used, its error shall not exceed ± 2°.
The directly measured parameters (see Clauses 3 and 4) shall be determined with a total
uncertainty better than ± 8 % of the limit value, or ± 8 % of the measured value, whichever is
higher. The total impedance of the circuit, excluding the appliance under test, but including
the internal impedance of the supply source, shall be equal to the reference impedance. The
stability and tolerance of this total impedance shall be adequate to ensure that the overall
uncertainty of ± 8 % is achieved during the whole assessment procedure.
If the source impedance is not well defined, for example where the source impedance is
subject to unpredictable variations, an impedance having resistance and inductance equal to
the reference impedance may be connected between the supply and the terminals of the
equipment under test. Measurements can then be made of the voltages at the source side of
the reference impedance and at the equipment terminals. In that case, the maximum relative
voltage change, d , measured at the supply terminals shall be less than 20 % of the
max
maximum value d measured at the equipment terminals.

max
NOTE The above method using a voltage source with undefined impedance is not used where the measured
values are close to the limits.
6.3 Test supply voltage
The test supply voltage (open-circuit voltage) shall be the rated voltage of the equipment. If a
voltage range is stipulated for the equipment, the test voltage shall be 230 V single-phase or
400 V three-phase. The test voltage shall be maintained within ± 2 % of the nominal value.
The frequency shall be 50 Hz ± 0,25 Hz.
The percentage total harmonic distortion of the supply voltage shall be less than 3 %.
Fluctuations of the test supply voltage during a test may be neglected if the P value,
st
produced from these fluctuations, is less than 0,4. If the measurements are made directly
using the mains supply, this condition shall be verified before and after each test. If
measurements are made using a controlled power source, this condition shall be verified
during calibration of the power source.
NOTE Frequency deviations can cause the measured P and P values to increase. Also, when testing a flicker
st lt
meter response according to Tables 1b and 2b in IEC 61000-4-15: 2010, the 50 Hz frequency is preferably
controlled to within ± 0,25 Hz.
6.4 Reference impedance
For equipment under test the reference impedance, Z according to IEC/TR 60725, is a
,
ref
conventional impedance used in the calculation and measurement of the directly measured
parameters, and the P and P values.

st lt
The impedance values of the various elements are given in Figure 1.
6.5 Observation period
The observation period, T , for the assessment of flicker values by flicker measurement,
p
flicker simulation, or analytical method shall be:
• for P , T = 10 min;
st p
61000-3-3 © IEC:2013 – 15 –
• for P , T = 2 h.
lt p
The observation period shall include that part of the whole operation cycle in which the
equipment under test produces the most unfavourable sequence of voltage changes.
For the assessment of P , the cycle of operation shall be repeated continuously, unless

st
stated otherwise in Annex A. The minimum time to restart the equipment shall be included in
this observation period when testing equipment that stops automatically at the end of a cycle
of operation which lasts for less than the observation period.
For P assessment, the cycle of operation shall not be repeated, unless stated otherwise in

lt
Annex A, when testing equipment with a cycle of operation of less than 2 h and which is not
normally used continuously.
NOTE For example, in the case of equipment with a cycle of operation lasting 45 min, five consecutive P values

st
are measured during a total period of 50 min, and the remaining seven P values in the 2 h observation period are

st
deemed to be zero.
6.6 General test conditions
The test conditions for the measurement of voltage fluctuations and flicker are given below.
For equipment not mentioned in Annex A, controls or automatic programs shall be set to
produce the most unfavourable sequence of voltage changes, using only those combinations
of controls and programmes which are mentioned by the manufacturer in the instruction
manual, or are otherwise likely to be used.
The equipment shall be tested in the condition in which it is supplied by the manufacturer.
Preliminary operation of motor drives may be needed before the tests to ensure that results
corresponding to those of normal use are obtained.
NOTE Operating conditions include mechanical and/or electrical loading conditions.
For motors, locked-rotor measurements may be used to determine the largest r.m.s. voltage
change, d , occurring during motor starting.
max
For equipment having several separately controlled circuits, the following conditions apply:
• each circuit shall be considered as a single item of equipment if it is intended to be used
independently, provided that the controls are not designed to switch at the same instant;
• if the controls of separate circuits are designed to switch simultaneously, the group of
circuits so controlled are considered as a single item of equipment.
For control systems regulating part of a load only, the voltage fluctuations produced by each
variable part of the load alone shall be considered.
Detailed type test conditions for some equipment are given in Annex A.

– 16 – 61000-3-3 © IEC:2013
S
R jX
A A
L1
G
R jX
A A L2
G
EUT
R jX
A A L3
G
R jX
N N N
M
IEC  945/13
Key
G voltage source in accordance with 6.3.
EUT equipment under test
M measuring equipment
S supply source consisting of the supply voltage generator G and reference impedance Z with the elements:
R = 0,24 Ω; jX = 0,15 Ω at 50 Hz;

A A
= 0,16 Ω; jX = 0,10 Ω at 50 Hz.
R
N N
NOTE 1 The elements include the actual generator impedance.
NOTE 2 When the source impedance is not well defined, see 6.2.
NOTE 3 In general, three-phase loads are balanced, and R and X can be neglected, as there is no current in

N N
the neutral wire.
Figure 1 – Reference network for single-phase and three-phase supplies
derived from a three-phase, four-wire supply

61000-3-3 © IEC:2013 – 17 –
See Clause 5 for limits in this area
0,3
0,1
–1 0 1 2 3 4
10 10 10 10 10 10
Number of voltage changes per minute
IEC  946/13
NOTE 1 1 200 voltage changes per minute give a 10 Hz flicker.
NOTE 2 Annex D includes a numerical table corresponding to Figure 2, taken from IEC/TR 61000-3-7:2008.
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes
st
1,0
0,8
T
0,6
d /2
max
≅
d /2 F × d
max max
0,4
T
0,2
d
max
F × d
≅
max
1 2 3
2 3 5 2 3 5
10 10 10
T  (ms)
IEC  947/13
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics

d  (%)
F
– 18 – 61000-3-3 © IEC:2013
1,4
1,2
1,0
0,8
0,6
T/2 T/2
≅
F × d
max
0,4
d
max
0,2 d
max ≅ F × d
max
T
1 2 3
2 3 5 2 3 5
10 10 10
T  (ms)
IEC  948/13
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics

1,2
10, 20
1,0
0,8
T (ms)
f
0,6
0,4
T 400
t Tail time
d
max
F × d
≅ max
0,2
T
Front time
f
1 2 3
2 3 5 2 3 5
10 10 1
...

IEC 61000-3-3 ®
Edition 3.2 2021-03
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection
Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤ 16 A par phase non
soumis à un raccordement conditionnel
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IEC 61000-3-3 ®
Edition 3.2 2021-03
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection
Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤ 16 A par phase non
soumis à un raccordement conditionnel
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.100.10 ISBN 978-2-8322-1078-2

IEC 61000-3-3 ®
Edition 3.2 2021-03
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection
Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤ 16 A par phase non
soumis à un raccordement conditionnel
– 2 – IEC 61000-3-3:2013+AMD1:2017
+AMD2:2021 CSV © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
INTRODUCTION to the corrigendum . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Assessment of voltage changes, voltage fluctuations and flicker . 10
4.1 Assessment of a relative voltage change, d(t) . 10
4.2 Assessment of the short-term flicker value, P . 11
st
4.2.1 General . 11
4.2.2 Flickermeter . 11
4.2.3 Simulation method . 11
4.2.4 Analytical method . 11
4.2.5 Use of P = 1 curve . 12

st
4.3 Assessment of long-term flicker value, P . 12
lt
5 Limits . 12
6 Test conditions . 13
6.1 General . 13
6.2 Measurement uncertainty . 14
6.3 Test supply voltage . 14
6.4 Reference impedance . 14
6.5 Observation period . 15
6.6 General test conditions . 15
Annex A (normative) Application of limits and type test conditions for specific
equipment . 19
A.1 Test conditions for cookers . 19
A.2 Test conditions for lighting and similar equipment . 20
A.3 Test conditions for washing machines . 21
A.4 Test conditions for tumbler dryers . 21
A.5 Test conditions for refrigerators and freezers . 21
A.6 Test conditions for copying machines, laser printers and similar appliances . 22
A.7 Test conditions for vacuum cleaners . 22
A.8 Test conditions for food mixers . 22
A.9 Test conditions for portable tools . 22
A.10 Test conditions for hairdryers and similar hair care equipment . 22
A.11 Test conditions for television sets, audio-equipment, computers, DVDs and
similar electronic equipment . 23
A.12 Test conditions for direct water heaters . 23
A.13 Test conditions for audio-frequency amplifiers . 24
A.14 Test conditions for air conditioners, dehumidifiers, heat pumps, and
commercial refrigerating equipment . 24
A.15 Test conditions for arc welding equipment and allied processes . 24
A.16 Coffee machines and tea machines . 27
A.17 Portable fan heaters . 27
A.18 Comfort fans and similar equipment . 28

+AMD2:2021 CSV © IEC 2021
Annex B (normative) Test conditions and procedures for measuring d voltage
max
changes caused by manual switching . 29
B.1 Overview . 29
B.2 Procedure . 29
Annex C (informative) Determination of steady state voltage and voltage change
characteristics, as defined in IEC 61000-4-15:2010 . 30
C.1 Overview . 30
C.2 Terms and definitions . 30
C.3 Steady state voltage, and voltage change characteristics . 31
C.4 Pictorial description of the directly measured parameters d , d(t), d and
c max,
T . 32
max
Annex D (informative) Input relative voltage fluctuation ∆V/V for P = 1,0 at output
st
[IEC/TR 61000-3-7:2008] . 35
Bibliography . 36

Figure 1 – Reference network for single-phase and three-phase supplies derived from
a three-phase, four-wire supply . 16
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes . 17
st
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics . 17
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics . 18
Figure 5 – Shape factor F for motor-start voltage characteristics having various front
times. 18
Figure C.1 – Evaluation of U (t) . 34
hp
Table 1 – Assessment method . 11
Table A.1 – Test conditions for hotplates . 19
Table A.2 – Electrode parameters . 25
Table A.3 – Frequency factor R related to repetition rate "r" . 26
Table C.1 – Test specification for d – d – t > (from Table 12 of
c max d(t) 3,3 %
IEC 61000-4-15: 2010). 33
Table C.2 – Test specification for d – d – t > (from Table 13 of
c max d(t) 3,3 %
IEC 61000-4-15: 2010). 33
Table D.1 – Input relative voltage fluctuation ∆V/V for P = 1,0 at output . 35
st
– 4 – IEC 61000-3-3:2013+AMD1:2017
+AMD2:2021 CSV © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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This consolidated version of the official IEC Standard and its amendments has been
prepared for user convenience.
IEC 61000-3-3 edition 3.2 contains the third edition (2013-05) [documents 77A/809/FDIS
and 77A/816/RVD], its amendment 1 (2017-05) [documents 77A/952/FDIS and
77A/960/RVD] and its amendment 2 (2021-03) [documents 77A/1075/CDV and
77A/1093/RVC] and its corrigendum (2022-01).
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendments 1 and 2. Additions are in green text, deletions are in
strikethrough red text. A separate Final version with all changes accepted is available
in this publication.
+AMD2:2021 CSV © IEC 2021
International Standard IEC 61000-3-3 has been prepared by subcommittee 77A: EMC – Low
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms part 3-3 of IEC 61000 series of standards. It has the status of a product
family standard.
This third edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) This edition takes account of the changes made in IEC 61000-4-15:2010.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61000 series, published under the general title Electromagnetic
compatibility (EMC), 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 document using a
colour printer.
– 6 – IEC 61000-3-3:2013+AMD1:2017
+AMD2:2021 CSV © IEC 2021
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 9: Miscellaneous
Each part is further subdivided into sections which are to be published either as International
Standards or as Technical Reports.
These standards and reports will be published in chronological order and numbered
accordingly.
INTRODUCTION to the corrigendum
During the final editing of the text for IEC 61000-3-3:2013/AMD2:2021 (Edition 3), a mistake
occurred and the sentence “P shall not be evaluated” is not displayed as a separate
lt
paragraph.
As a result, this could lead to a wrong interpretation of the text and to wrong Pass/Fail results.
This corrigendum is needed to clarify that the text “P shall not be evaluated” applies to all
lt
equipment in Clause A.16.
+AMD2:2021 CSV © IEC 2021
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

1 Scope
This part of IEC 61000 is concerned with the limitation of voltage fluctuations and flicker
impressed on the public low-voltage system.
It specifies limits of voltage changes which may be produced by an equipment tested under
specified conditions and gives guidance on methods of assessment.
This part of IEC 61000 is applicable to electrical and electronic equipment having an input
current equal to or less than 16 A per phase, intended to be connected to public low-voltage
distribution systems of between 220 V and 250 V line to neutral at 50 Hz, and not subject to
conditional connection.
Equipment which does not comply with the limits of this part of IEC 61000 when tested with
the reference impedance Z of 6.4, and which therefore cannot be declared compliant with
ref
this part, may be retested or evaluated to show conformity with IEC 61000-3-11. Part 3-11 is
applicable to equipment with rated input current ≤ 75 A per phase and subject to conditional
connection.
The tests according to this part are type tests. Particular test conditions are given in Annex A
and the test circuit is shown in Figure 1.
NOTE 1 The limits in this standard relate to the voltage changes experienced by consumers connected at the
interface between the public supply low-voltage network and the equipment user’s installation. Consequently, if the
actual impedance of the supply at the supply terminals of equipment connected within the equipment user’s
installation exceeds the test impedance, it is possible that supply disturbance exceeding the limits could occur.
NOTE 2 The limits in this standard are based mainly on the subjective severity of flicker imposed on the light from
230 V 60 W coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage less
than 220 V line to neutral and/or frequency of 60 Hz, the limits and reference circuit values are under
consideration.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC/TR 60725, Consideration of reference impedances and public supply impedances for use
in determining disturbance characteristics of electrical equipment having a rated current
≤ 75 A per phase
IEC 60974-1, Arc welding equipment – Part 1: Welding power sources
IEC 61000-3-2, Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic
current emissions (equipment input current ≤ 16 A per phase)

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IEC 61000-3-11, Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of
voltage changes, voltage fluctuations and flicker in public low-voltage supply systems –
Equipment with rated current ≤ 75 A and subject to conditional connection
IEC 61000-4-15:2010, Electromagnetic compatibility (EMC) – Part 4-15: Testing and
measurement techniques – Flickermeter – Functional and design specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flicker
impression of unsteadiness of visual sensation induced by a light stimulus whose luminance
or spectral distribution fluctuates with time
[SOURCE: IEC 60050-161:1990, 161-08-13]
3.2
voltage change characteristic
d(t)
time function of the relative r.m.s. voltage change evaluated as a single value for each
successive half period between zero-crossings of the source voltage, except during time
intervals in which the voltage is in a steady-state condition for at least 1 s
Note 1 to entry: For detailed information about the evaluation of a voltage change characteristic and the definition
of a steady state condition see Annex C and IEC 61000-4-15:2010.
3.3
d
c
maximum steady state voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
c
3.4
d
max
maximum absolute voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
max
3.5
T
max
maximum time duration during the observation period that the voltage deviation d(t) exceeds
the limit for d
c
Note 1 to entry: During a voltage change characteristic the time duration T is accumulated until a new steady
max
state condition is established.
Note 2 to entry: The T limit evaluation in this standard is generally intended to evaluate the inrush current
max
pattern of the equipment under test. Thus, as soon as a new steady state condition is established, the T
max
evaluation is ended. When a new voltage change occurs that exceeds the limit for d , a new T evaluation is
c max
started. The maximum duration that d(t) exceeds the limit for d for any of the individual T evaluations during the
c max
observation period, is used for the comparison against the T limit, and is reported for the test.
max
3.6
nominal test voltage
U
n
nominal test voltage used to calculate percentages for the various directly measured
parameters
+AMD2:2021 CSV © IEC 2021
Note 1 to entry: If no steady state condition is achieved during the observation period, U is used for the
n
calculation of d and T .
max max
Note 2 to entry: U is not necessarily equal to the nominal voltage of the public supply.
n
3.7
P
st
short-term flicker severity
Note 1 to entry: If not specified differently, the P evaluation time is 10 minutes. For the purpose of power quality
st
surveys and studies, other time intervals may be used, and have to be defined in the index. For example a 1
minute interval should be written as P
st,1min.
3.8
P
lt
long-term flicker severity
N
P
∑
st,i
i =1
P =
lt
N
where P (i = 1, 2, 3, .) are consecutive readings of the short-term severity P
st
st,i
Note 1 to entry: Unless otherwise specified, P is calculated over discrete T periods. Each time a T period
lt long long
has expired, a new P calculation is started.
lt
3.9
flickermeter
instrument designed to measure any quantity representative of flicker
Note 1 to entry: Measurements are normally P and P and may also include the directly measured parameters
st lt
specified in 3.2 to 3.5.
[SOURCE: IEC 60050-161:1990, 161-08-14]
3.10
flicker impression time
t
f
value with a time dimension which describes the flicker impression of a voltage change
characteristic
3.11
shape factor
F
value derived from the type of voltage fluctuation, such as a step, double step, or ramp
pattern
Note 1 to entry: The shape factor is mainly needed when the analytical method is used to calculate P .
st
3.12
interface point
interface between a public supply network and a user’s installation
3.13
conditional connection
connection of equipment requiring the user’s supply at the interface point to have an
impedance lower than the reference impedance Z in order that the equipment emissions
ref
comply with the limits in this part

– 10 – IEC 61000-3-3:2013+AMD1:2017
+AMD2:2021 CSV © IEC 2021
Note 1 to entry: Meeting the voltage change limits may not be the only condition for connection; emission limits
for other phenomena such as harmonics, may also have to be satisfied.
4 Assessment of voltage changes, voltage fluctuations and flicker
4.1 Assessment of a relative voltage change, d(t)
The basis for flicker evaluation is the voltage change characteristic at the terminals of the
equipment under test, that is the difference ∆ U (t) of any two successive values of the
hp
phase-to-neutral voltages U (t ) and U (t ):
hp 1 hp 2
∆ U (t) = U (t ) – U (t ) (1)
hp hp 1 hp 2
NOTE 1 See Annex C for relevant definitions that are taken from IEC 61000-4-15:2010.
The r.m.s. values U (t ), U (t ) of the voltage shall be measured or calculated. When
hp 1 hp 2
deducing r.m.s. values from oscillographic waveforms, account should be taken of any
waveform distortion that may be present.
The voltage change at the EUT terminals, ∆U, is due to the change of the voltage drop across
the complex reference impedance Z, caused by the complex fundamental input current
change, ∆I, of the equipment under test. ∆I and ∆I are the active and reactive parts
p q
respectively of the current change, ∆I.
∆I = ∆I – j∆I = I(t ) – I(t ) (2)
p q
1 2
NOTE 2 I is positive for lagging currents and negative for leading currents.
q
NOTE 3 If the harmonic distortion of the currents I(t ) and I(t ) is less than 10 %, the total r.m.s. value can be
1 2
applied instead of the r.m.s. values of their fundamental currents, taking account of the phase angles of the
fundamental currents.
NOTE 4 For single-phase and symmetrical three-phase equipment the voltage change can be, provided X is
positive (inductive), approximated to:
∆U = ∆I R + ∆I X (3)
hp p q
where ∆I and ∆I are the active and reactive parts respectively of the current change ∆I and R and X are the
p q
elements of the complex reference impedance Z (see Figure 1).
The relative voltage change is given by:
d = ∆U /U (4)
hp n
The d evaluation ends as soon as a new steady state condition is established, or at the
max,i
end of the observation period. The polarity of change(s) may be indicated as follows: if the
maximum voltage deviation is observed during a reduction in voltage with respect to the
previous d the resulting d value is positive; if the maximum voltage deviation is
end,i max,i
observed during a voltage increase with respect to the previous d the resulting d
end,i max,i
value is negative.
+AMD2:2021 CSV © IEC 2021
4.2 Assessment of the short-term flicker value, P
st
4.2.1 General
Table 1 shows alternative methods for evaluating P , due to voltage fluctuations of different

st
types; in all cases direct measurement (with a flickermeter) is acceptable:
Table 1 – Assessment method
Types of voltage fluctuations Method for evaluating P
st
All voltage fluctuations (on-line evaluation) Flickermeter
All voltage fluctuations where U(t) is known Simulation
Voltage change characteristics according to Figures 3 Analytical
to 5 with an occurrence rate less than 1 per second
Rectangular voltage change at equal intervals Use of the P = 1 curve of Figure 2

st
4.2.2 Flickermeter
All types of voltage fluctuations may be assessed by direct measurement using a flickermeter
which complies with the specification given in IEC 61000-4-15:2010, and is connected as
described in this standard. This is the reference method for application of the limits.
4.2.3 Simulation method
In the case where the relative voltage change characteristic d(t) is known, P can be

st
evaluated using a computer simulation.
4.2.4 Analytical method
4.2.4.1 General
For voltage change characteristics of the types shown in Figures 3, 4 and 5, the P value can

st
be evaluated by an analytical method using Equations (5) and (6).
NOTE 1 The value of P obtained using this method is expected to be within ± 10 % of the result which would be
st
obtained by direct measurement (reference method).
NOTE 2 This method is not used if the time duration between the end of one voltage change and the start of the
next is less than 1 s.
4.2.4.2 Description of the analytical method
Each relative voltage change characteristic shall be expressed by a flicker impression time, t ,
f
in seconds:
3,2
t = 2,3 (Fd ) (5)
f max
– the maximum relative voltage change d is expressed as a percentage of the nominal

max
voltage U ;
n
– the shape factor, F, is associated with the shape of the voltage change characteristic (see
4.2.4.3).
The sum of the flicker impression times, Σt , of all evaluation periods within a total interval of
f
the length T , in seconds, is the basis for the P evaluation. If the total time interval T is

p st p
chosen according to 6.5, it is an "observation period", and:

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+AMD2:2021 CSV © IEC 2021
1/3,2
P = (Σt /T ) (6)
st f p
4.2.4.3 Shape factor
The shape factor, F, converts a relative voltage change characteristic d(t) into a flicker
equivalent relative step voltage change (Fd ).
max
NOTE 1 The shape factor, F, is equal to 1,0 for step voltage changes.
NOTE 2 The relative voltage change characteristic can be measured directly (see Figure 1) or calculated from the
r.m.s. current of the equipment under test (see Equations (1) to (4)).
The relative voltage change characteristic shall be obtained from a time progression of U (t)
hp
(see Figure C.1).
The shape factor may be deduced from Figures 3, 4 and 5, provided that the relative voltage
change characteristic matches a characteristic shown in these figures. If the characteristics
match, proceed as follows:
– find the maximum relative voltage change d ; and
max
– find the time T (in ms) appropriate to the voltage change characteristic as shown in
Figures 3, 4 and 5 and, using this value, obtain the required shape factor, F.
NOTE 3 Extrapolation outside the range of the figures would lead to unacceptable errors.
4.2.5 Use of P = 1 curve
st
In the case of rectangular voltage changes of the same amplitude d separated by equal time
intervals, the curve of Figure 2 may be used to deduce the amplitude corresponding to P = 1

st
for a particular rate of repetition; this amplitude is called d . The P value corresponding to

lim st
the voltage change d is then given by P = d/d .

st lim
4.3 Assessment of long-term flicker value, P
lt
The long-term flicker value P shall be applied with the value of N = 12 (see 6.5).

lt
It is generally necessary to assess the value of P for equipment which is normally operated
lt
for more than 30 min at a time.
5 Limits
The limits shall be applicable to voltage fluctuations and flicker at the supply terminals of the
equipment under test, measured or calculated according to Clause 4 under test conditions
described in Clause 6 and Annex A. Tests made to prove compliance with the limits are
considered to be type tests.
The following limits apply:
• the value of P shall not be greater than 1,0;
st
• the value of P shall not be greater than 0,65;
lt
• T , the accumulated time value of d(t) with a deviation exceeding 3,3 % during a single
max
voltage change at the EUT terminals, shall not exceed 500 ms;
• the maximum relative steady-state voltage change, d , shall not exceed 3,3 %;
c
• the maximum relative voltage change d , shall not exceed:
max
a) 4 % without additional conditions;
b) 6 % for equipment which is:

+AMD2:2021 CSV © IEC 2021
– switched manually, or
– switched automatically more frequently than twice per day, and also has either a
delayed restart (the delay being not less than a few tens of seconds), or manual
restart, after a power supply interruption.
NOTE The cycling frequency is further limited by the P and P limits. For example: a d of 6 % producing a
st lt max
rectangular voltage change characteristic twice per hour gives a P of about 0,65.
lt
c) 7 % for equipment which is:
– attended whilst in use (for example: hair dryers, vacuum cleaners, kitchen
equipment such as mixers, garden equipment such as lawn mowers, portable tools
such as electric drills), or
– switched on automatically, or is intended to be switched on manually, no more than
twice per day, and also has either a delayed restart (the delay being not less than a
few tens of seconds) or manual restart, after a power supply interruption.
In the case of equipment having several separately controlled circuits in accordance with 6.6,
limits b) and c) shall apply only if there is delayed or manual restart after a power supply
interruption; for all equipment with automatic switching which is energized immediately on
restoration of supply after a power supply interruption, limits a) shall apply.
For all equipment with manual switching, limits b) or c) shall apply depending on the rate of
switching typical of normal operation.
P and P requirements shall not be applied to voltage changes caused by manual switching.

st lt
The limits shall not be applied to voltage changes associated with emergency switching or
emergency interruptions.
6 Test conditions
6.1 General
Tests need not be made on equipment which is unlikely to produce significant voltage
fluctuations or flicker. Where it is considered necessary to conduct tests, the equipment shall
comply with all limits in Clause 5 for the tests described in Annex A unless there are specific
exclusions for a particular type of equipment.
It may be necessary to determine, by examination of the circuit diagram and specification of
the equipment and by a short functional test, whether significant voltage fluctuations are likely
to be produced.
For voltage changes caused by manual switching, equipment is deemed to comply without
further testing if the maximum r.m.s. input current (including inrush current) evaluated over
each 10 ms half-period between zero-crossings does not exceed 20 A, and the supply current
after inrush is within a variation band of 1,5 A.
If measurement methods are used, the maximum relative voltage change d caused by

max
manual switching shall be measured in accordance with Annex B.
Tests to prove the compliance of the equipment with the limits shall be made using the test
circuit in Figure 1.
The test circuit consists of:
• the test supply voltage (see 6.3);
• the reference impedance (see 6.4);

– 14 – IEC 61000-3-3:2013+AMD1:2017
+AMD2:2021 CSV © IEC 2021
• the equipment under test (see Annex A);
• if necessary, a flickermeter (see IEC 61000-4-15:2010).
The relative voltage change d (t) may be measured directly or derived from the r.m.s. current
hp
as described in 4.1. To determine the P value of the equipment under test, one of the

st
methods described in 4.2 shall be used. In case of doubt, the P shall be measured using

st
the reference method with a flickermeter.
NOTE If balanced multiphase equipment is tested, it is acceptable to measure only one of the three line-to-neutral
voltages.
6.2 Measurement uncertainty
The magnitude of the current shall be measured with an accuracy of ± (1 % + 10 mA) or
better, where the 1 % is referred to the measured value. If, instead of active and reactive
current, the phase angle is used, its error shall not exceed ± 2°.
The directly measured parameters (see Clauses 3 and 4) shall be determined with a total
uncertainty better than ± 8 % of the limit value, or ± 8 % of the measured value, whichever is
higher. The total impedance of the circuit, excluding the appliance under test, but including
the internal impedance of the supply source, shall be equal to the reference impedance. The
stability and tolerance of this total impedance shall be adequate to ensure that the overall
uncertainty of ± 8 % is achieved during the whole assessment procedure.
If the source impedance is not well defined, for example where the source impedance is
subject to unpredictable variations, an impedance having resistance and inductance equal to
the reference impedance may be connected between the supply and the terminals of the
equipment under test. Measurements can then be made of the voltages at the source side of
the reference impedance and at the equipment terminals. In that case, the maximum relative
voltage change, d , measured at the supply terminals shall be less than 20 % of the
max
maximum value d measured at the equipment terminals.

max
NOTE The above method using a voltage source with undefined impedance is not used where the measured
values are close to the limits.
6.3 Test supply voltage
The test supply voltage (open-circuit voltage) shall be the rated voltage of the equipment. If a
voltage range is stipulated for the equipment, the test voltage shall be 230 V single-phase or
400 V three-phase. The test voltage shall be maintained within ± 2 % of the nominal value.
The frequency shall be 50 Hz ± 0,25 Hz.
The percentage total harmonic distortion of the supply voltage shall be less than 3 %.
Fluctuations of the test supply voltage duri
...

IEC 61000-3-3 ®
Edition 3.1 2017-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤16 A par phase et non
soumis à un raccordement conditionnel

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IEC 61000-3-3 ®
Edition 3.1 2017-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electromagnetic compatibility (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker

in public low-voltage supply systems, for equipment with rated current ≤ 16 A

per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –

Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de

tension et du papillotement dans les réseaux publics d'alimentation basse

tension, pour les matériels ayant un courant assigné ≤16 A par phase et non

soumis à un raccordement conditionnel

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.100.10 ISBN 978-2-8322-4401-2

IEC 61000-3-3 ®
Edition 3.1 2017-05
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Electromagnetic compatibility (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and flicker
in public low-voltage supply systems, for equipment with rated current ≤ 16 A
per phase and not subject to conditional connection

Compatibilité électromagnétique (CEM) –
Partie 3-3: Limites – Limitation des variations de tension, des fluctuations de
tension et du papillotement dans les réseaux publics d'alimentation basse
tension, pour les matériels ayant un courant assigné ≤16 A par phase et non
soumis à un raccordement conditionnel

– 2 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Assessment of voltage changes, voltage fluctuations and flicker . 10
4.1 Assessment of a relative voltage change, d(t) . 10
4.2 Assessment of the short-term flicker value, P . 11
st
4.2.1 General . 11
4.2.2 Flickermeter . 11
4.2.3 Simulation method . 11
4.2.4 Analytical method . 11
4.2.5 Use of P = 1 curve . 12

st
4.3 Assessment of long-term flicker value, P . 12
lt
5 Limits . 12
6 Test conditions . 13
6.1 General . 13
6.2 Measurement uncertainty . 14
6.3 Test supply voltage . 14
6.4 Reference impedance . 14
6.5 Observation period . 15
6.6 General test conditions . 15
Annex A (normative) Application of limits and type test conditions for specific
equipment . 19
Annex B (normative) Test conditions and procedures for measuring d voltage
max
changes caused by manual switching . 27
Annex C (informative) Determination of steady state voltage and voltage change
characteristics, as defined in IEC 61000-4-15:2010 . 28
Annex D (informative) Input relative voltage fluctuation ∆V/V for P = 1,0 at output
st
[IEC/TR 61000-3-7:2008] . 33
Bibliography . 34

Figure 1 – Reference network for single-phase and three-phase supplies derived from
a three-phase, four-wire supply . 16
Figure 2 – Curve for P = 1 for rectangular equidistant voltage changes . 17
st
Figure 3 – Shape factors F for double-step and ramp-voltage characteristics . 17
Figure 4 – Shape factors F for rectangular and triangular voltage characteristics . 18
Figure 5 – Shape factor F for motor-start voltage characteristics having various front
times. 18
Figure C.1 – Evaluation of U (t) . 32
hp
Table 1 – Assessment method . 11
Table A.1 – Test conditions for hotplates . 19
Table A.2 – Electrode parameters . 24

© IEC 2017
Table A.3 – Frequency factor R related to repetition rate "r" . 25
Table C.1 – Test specification for d – d – t (from Table 12 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table C.2 – Test specification for d – d – t (from Table 13 of
c max d(t) > 3,3 %
IEC 61000-4-15: 2010). 31
Table D.1 – Input relative voltage fluctuation ∆V/V for P = 1,0 at output . 33
st
– 4 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection
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-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
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 the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 61000-3-3 edition 3.1 contains the third edition (2013-05) [documents 77A/809/FDIS and
77A/816/RVD] and its amendment 1 (2017-05) [documents 77A/952/FDIS and 77A/960/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text.
A separate Final version with all changes accepted is available in this publication.

© IEC 2017
International Standard IEC 61000-3-3 has been prepared by subcommittee 77A: EMC – Low
frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms part 3-3 of IEC 61000 series of standards. It has the status of a product
family standard.
This third edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) This edition takes account of the changes made in IEC 61000-4-15:2010.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61000 series, published under the general title Electromagnetic
compatibility (EMC), can be found on the IEC website.
The committee has decided that the contents of the base publication and its amendment 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.
– 6 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 9: Miscellaneous
Each part is further subdivided into sections which are to be published either as International
Standards or as Technical Reports.
These standards and reports will be published in chronological order and numbered
accordingly.
© IEC 2017
ELECTROMAGNETIC COMPATIBILITY (EMC) –

Part 3-3: Limits – Limitation of voltage changes, voltage fluctuations and
flicker in public low-voltage supply systems, for equipment with rated
current ≤ 16 A per phase and not subject to conditional connection

1 Scope
This part of IEC 61000 is concerned with the limitation of voltage fluctuations and flicker
impressed on the public low-voltage system.
It specifies limits of voltage changes which may be produced by an equipment tested under
specified conditions and gives guidance on methods of assessment.
This part of IEC 61000 is applicable to electrical and electronic equipment having an input
current equal to or less than 16 A per phase, intended to be connected to public low-voltage
distribution systems of between 220 V and 250 V line to neutral at 50 Hz, and not subject to
conditional connection.
Equipment which does not comply with the limits of this part of IEC 61000 when tested with
the reference impedance Z of 6.4, and which therefore cannot be declared compliant with
ref
this part, may be retested or evaluated to show conformity with IEC 61000-3-11. Part 3-11 is
applicable to equipment with rated input current ≤ 75 A per phase and subject to conditional
connection.
The tests according to this part are type tests. Particular test conditions are given in Annex A
and the test circuit is shown in Figure 1.
NOTE 1 The limits in this standard relate to the voltage changes experienced by consumers connected at the
interface between the public supply low-voltage network and the equipment user’s installation. Consequently, if the
actual impedance of the supply at the supply terminals of equipment connected within the equipment user’s
installation exceeds the test impedance, it is possible that supply disturbance exceeding the limits could occur.
NOTE 2 The limits in this standard are based mainly on the subjective severity of flicker imposed on the light from
230 V 60 W coiled-coil filament lamps by fluctuations of the supply voltage. For systems with nominal voltage less
than 220 V line to neutral and/or frequency of 60 Hz, the limits and reference circuit values are under
consideration.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC/TR 60725, Consideration of reference impedances and public supply impedances for use
in determining disturbance characteristics of electrical equipment having a rated current
≤ 75 A per phase
IEC 60974-1, Arc welding equipment – Part 1: Welding power sources
IEC 61000-3-2, Electromagnetic compatibility (EMC) – Part 3-2: Limits – Limits for harmonic
current emissions (equipment input current ≤ 16 A per phase)

– 8 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
IEC 61000-3-11, Electromagnetic compatibility (EMC) – Part 3-11: Limits – Limitation of
voltage changes, voltage fluctuations and flicker in public low-voltage supply systems –
Equipment with rated current ≤ 75 A and subject to conditional connection
IEC 61000-4-15:2010, Electromagnetic compatibility (EMC) – Part 4-15: Testing and
measurement techniques – Flickermeter – Functional and design specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flicker
impression of unsteadiness of visual sensation induced by a light stimulus whose luminance
or spectral distribution fluctuates with time
[SOURCE: IEC 60050-161:1990, 161-08-13]
3.2
voltage change characteristic
d(t)
time function of the relative r.m.s. voltage change evaluated as a single value for each
successive half period between zero-crossings of the source voltage, except during time
intervals in which the voltage is in a steady-state condition for at least 1 s
Note 1 to entry: For detailed information about the evaluation of a voltage change characteristic and the definition
of a steady state condition see Annex C and IEC 61000-4-15:2010.
3.3
d
c
maximum steady state voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
c
3.4
d
max
maximum absolute voltage change during an observation period
Note 1 to entry: For detailed information about the calculation of d see Annex C and IEC 61000-4-15:2010.
max
3.5
T
max
maximum time duration during the observation period that the voltage deviation d(t) exceeds
the limit for d
c
Note 1 to entry: During a voltage change characteristic the time duration T is accumulated until a new steady
max
state condition is established.
Note 2 to entry: The T limit evaluation in this standard is generally intended to evaluate the inrush current
max
pattern of the equipment under test. Thus, as soon as a new steady state condition is established, the T
max
evaluation is ended. When a new voltage change occurs that exceeds the limit for d , a new T evaluation is
c max
started. The maximum duration that d(t) exceeds the limit for d for any of the individual T evaluations during the
c max
observation period, is used for the comparison against the T limit, and is reported for the test.
max
3.6
nominal test voltage
U
n
nominal test voltage used to calculate percentages for the various directly measured
parameters
© IEC 2017
Note 1 to entry: If no steady state condition is achieved during the observation period, U is used for the
n
calculation of d and T .
max max
Note 2 to entry: U is not necessarily equal to the nominal voltage of the public supply.
n
3.7
P
st
short-term flicker severity
Note 1 to entry: If not specified differently, the P evaluation time is 10 minutes. For the purpose of power quality
st
surveys and studies, other time intervals may be used, and have to be defined in the index. For example a 1
minute interval should be written as P
st,1min.
3.8
P
lt
long-term flicker severity
N
P
∑
st,i
i =1
P =
lt
N
where P (i = 1, 2, 3, .) are consecutive readings of the short-term severity P
st
st,i
Note 1 to entry: Unless otherwise specified, P is calculated over discrete T periods. Each time a T period
lt long long
has expired, a new P calculation is started.
lt
3.9
flickermeter
instrument designed to measure any quantity representative of flicker
Note 1 to entry: Measurements are normally P and P and may also include the directly measured parameters
st lt
specified in 3.2 to 3.5.
[SOURCE: IEC 60050-161:1990, 161-08-14]
3.10
flicker impression time
t
f
value with a time dimension which describes the flicker impression of a voltage change
characteristic
3.11
shape factor
F
value derived from the type of voltage fluctuation, such as a step, double step, or ramp
pattern
Note 1 to entry: The shape factor is mainly needed when the analytical method is used to calculate P .
st
3.12
interface point
interface between a public supply network and a user’s installation
3.13
conditional connection
connection of equipment requiring the user’s supply at the interface point to have an
impedance lower than the reference impedance Z in order that the equipment emissions
ref
comply with the limits in this part

– 10 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
Note 1 to entry: Meeting the voltage change limits may not be the only condition for connection; emission limits
for other phenomena such as harmonics, may also have to be satisfied.
4 Assessment of voltage changes, voltage fluctuations and flicker
4.1 Assessment of a relative voltage change, d(t)
The basis for flicker evaluation is the voltage change characteristic at the terminals of the
equipment under test, that is the difference ∆ U (t) of any two successive values of the
hp
phase-to-neutral voltages U (t ) and U (t ):
hp 1 hp 2
∆ U (t) = U (t ) – U (t ) (1)
hp hp 1 hp 2
NOTE 1 See Annex C for relevant definitions that are taken from IEC 61000-4-15:2010.
The r.m.s. values U (t ), U (t ) of the voltage shall be measured or calculated. When
hp 1 hp 2
deducing r.m.s. values from oscillographic waveforms, account should be taken of any
waveform distortion that may be present.
The voltage change at the EUT terminals, ∆U, is due to the change of the voltage drop across
the complex reference impedance Z, caused by the complex fundamental input current
change, ∆I, of the equipment under test. ∆I and ∆I are the active and reactive parts
p q
respectively of the current change, ∆I.
∆I = ∆I – j∆I = I(t ) – I(t ) (2)
p q
1 2
NOTE 2 I is positive for lagging currents and negative for leading currents.
q
NOTE 3 If the harmonic distortion of the currents I(t ) and I(t ) is less than 10 %, the total r.m.s. value can be
1 2
applied instead of the r.m.s. values of their fundamental currents, taking account of the phase angles of the
fundamental currents.
NOTE 4 For single-phase and symmetrical three-phase equipment the voltage change can be, provided X is
positive (inductive), approximated to:
∆U = ∆I R + ∆I X (3)
hp p q
where ∆I and ∆I are the active and reactive parts respectively of the current change ∆I and R and X are the
p q
elements of the complex reference impedance Z (see Figure 1).
The relative voltage change is given by:
d = ∆U /U (4)
hp n
The d evaluation ends as soon as a new steady state condition is established, or at the
max,i
end of the observation period. The polarity of change(s) may be indicated as follows: if the
maximum voltage deviation is observed during a reduction in voltage with respect to the
previous d the resulting d value is positive; if the maximum voltage deviation is
end,i max,i
observed during a voltage increase with respect to the previous d the resulting d
end,i max,i
value is negative.
© IEC 2017
4.2 Assessment of the short-term flicker value, P
st
4.2.1 General
Table 1 shows alternative methods for evaluating P , due to voltage fluctuations of different

st
types; in all cases direct measurement (with a flickermeter) is acceptable:
Table 1 – Assessment method
Types of voltage fluctuations Method for evaluating P
st
All voltage fluctuations (on-line evaluation) Flickermeter
All voltage fluctuations where U(t) is known
Simulation
Voltage change characteristics according to Figures 3 Analytical
to 5 with an occurrence rate less than 1 per second
Rectangular voltage change at equal intervals Use of the P = 1 curve of Figure 2

st
4.2.2 Flickermeter
All types of voltage fluctuations may be assessed by direct measurement using a flickermeter
which complies with the specification given in IEC 61000-4-15:2010, and is connected as
described in this standard. This is the reference method for application of the limits.
4.2.3 Simulation method
In the case where the relative voltage change characteristic d(t) is known, P can be

st
evaluated using a computer simulation.
4.2.4 Analytical method
4.2.4.1 General
For voltage change characteristics of the types shown in Figures 3, 4 and 5, the P value can

st
be evaluated by an analytical method using Equations (5) and (6).
NOTE 1 The value of P obtained using this method is expected to be within ± 10 % of the result which would be
st
obtained by direct measurement (reference method).
NOTE 2 This method is not used if the time duration between the end of one voltage change and the start of the
next is less than 1 s.
4.2.4.2 Description of the analytical method
Each relative voltage change characteristic shall be expressed by a flicker impression time, t ,
f
in seconds:
3,2
t = 2,3 (Fd ) (5)
f max
– the maximum relative voltage change d is expressed as a percentage of the nominal

max
voltage U ;
n
– the shape factor, F, is associated with the shape of the voltage change characteristic (see
4.2.4.3).
The sum of the flicker impression times, Σt , of all evaluation periods within a total interval of
f
the length T , in seconds, is the basis for the P evaluation. If the total time interval T is

p st p
chosen according to 6.5, it is an "observation period", and:

– 12 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
1/3,2
P = (Σt /T ) (6)
st f p
4.2.4.3 Shape factor
The shape factor, F, converts a relative voltage change characteristic d(t) into a flicker
equivalent relative step voltage change (Fd ).
max
NOTE 1 The shape factor, F, is equal to 1,0 for step voltage changes.
NOTE 2 The relative voltage change characteristic can be measured directly (see Figure 1) or calculated from the
r.m.s. current of the equipment under test (see Equations (1) to (4)).
The relative voltage change characteristic shall be obtained from a time progression of U (t)
hp
(see Figure C.1).
The shape factor may be deduced from Figures 3, 4 and 5, provided that the relative voltage
change characteristic matches a characteristic shown in these figures. If the characteristics
match, proceed as follows:
– find the maximum relative voltage change d ; and
max
– find the time T (in ms) appropriate to the voltage change characteristic as shown in
Figures 3, 4 and 5 and, using this value, obtain the required shape factor, F.
NOTE 3 Extrapolation outside the range of the figures would lead to unacceptable errors.
4.2.5 Use of P = 1 curve
st
In the case of rectangular voltage changes of the same amplitude d separated by equal time
intervals, the curve of Figure 2 may be used to deduce the amplitude corresponding to P = 1

st
for a particular rate of repetition; this amplitude is called d . The P value corresponding to

lim st
the voltage change d is then given by P = d/d .

st lim
4.3 Assessment of long-term flicker value, P
lt
The long-term flicker value P shall be applied with the value of N = 12 (see 6.5).

lt
It is generally necessary to assess the value of P for equipment which is normally operated

lt
for more than 30 min at a time.
5 Limits
The limits shall be applicable to voltage fluctuations and flicker at the supply terminals of the
equipment under test, measured or calculated according to Clause 4 under test conditions
described in Clause 6 and Annex A. Tests made to prove compliance with the limits are
considered to be type tests.
The following limits apply:
• the value of P shall not be greater than 1,0;
st
• the value of P shall not be greater than 0,65;
lt
• T , the accumulated time value of d(t) with a deviation exceeding 3,3 % during a single
max
voltage change at the EUT terminals, shall not exceed 500 ms;
• the maximum relative steady-state voltage change, d , shall not exceed 3,3 %;
c
• the maximum relative voltage change d , shall not exceed:
max
a) 4 % without additional conditions;
b) 6 % for equipment which is:

© IEC 2017
– switched manually, or
– switched automatically more frequently than twice per day, and also has either a
delayed restart (the delay being not less than a few tens of seconds), or manual
restart, after a power supply interruption.
NOTE The cycling frequency is further limited by the P and P limits. For example: a d of 6 % producing a
st lt max
rectangular voltage change characteristic twice per hour gives a P of about 0,65.
lt
c) 7 % for equipment which is:
– attended whilst in use (for example: hair dryers, vacuum cleaners, kitchen
equipment such as mixers, garden equipment such as lawn mowers, portable tools
such as electric drills), or
– switched on automatically, or is intended to be switched on manually, no more than
twice per day, and also has either a delayed restart (the delay being not less than a
few tens of seconds) or manual restart, after a power supply interruption.
In the case of equipment having several separately controlled circuits in accordance with 6.6,
limits b) and c) shall apply only if there is delayed or manual restart after a power supply
interruption; for all equipment with automatic switching which is energized immediately on
restoration of supply after a power supply interruption, limits a) shall apply.
For all equipment with manual switching, limits b) or c) shall apply depending on the rate of
switching typical of normal operation.
P and P requirements shall not be applied to voltage changes caused by manual switching.

st lt
The limits shall not be applied to voltage changes associated with emergency switching or
emergency interruptions.
6 Test conditions
6.1 General
Tests need not be made on equipment which is unlikely to produce significant voltage
fluctuations or flicker. Where it is considered necessary to conduct tests, the equipment shall
comply with all limits in Clause 5 for the tests described in Annex A unless there are specific
exclusions for a particular type of equipment.
It may be necessary to determine, by examination of the circuit diagram and specification of
the equipment and by a short functional test, whether significant voltage fluctuations are likely
to be produced.
For voltage changes caused by manual switching, equipment is deemed to comply without
further testing if the maximum r.m.s. input current (including inrush current) evaluated over
each 10 ms half-period between zero-crossings does not exceed 20 A, and the supply current
after inrush is within a variation band of 1,5 A.
If measurement methods are used, the maximum relative voltage change d caused by

max
manual switching shall be measured in accordance with Annex B.
Tests to prove the compliance of the equipment with the limits shall be made using the test
circuit in Figure 1.
The test circuit consists of:
• the test supply voltage (see 6.3);
• the reference impedance (see 6.4);

– 14 – IEC 61000-3-3:2013+AMD1:2017 CSV
© IEC 2017
• the equipment under test (see Annex A);
• if necessary, a flickermeter (see IEC 61000-4-15:2010).
The relative voltage change d (t) may be measured directly or derived from the r.m.s. current
hp
as described in 4.1. To determine the P value of the equipment under test, one of the

st
methods described in 4.2 shall be used. In case of doubt, the P shall be measured using

st
the reference method with a flickermeter.
NOTE If balanced multiphase equipment is tested, it is acceptable to measure only one of the three line-to-neutral
voltages.
6.2 Measurement uncertainty
The magnitude of the current shall be measured with an accuracy of ± (1 % + 10 mA) or
better, where the 1 % is referred to the measured value. If, instead of active and reactive
current, the phase angle is used, its error shall not exceed ± 2°.
The directly measured parameters (see Clauses 3 and 4) shall be determined with a total
uncertainty better than ± 8 % of the limit value, or ± 8 % of the measured value, whichever is
higher. The total impedance of the circuit, excluding the appliance under test, but including
the internal impedance of the supply source, shall be equal to the reference impedance. The
stability and tolerance of this total impedance shall be adequate to ensure that the overall
uncertainty of ± 8 % is achieved during the whole assessment procedure.
If the source impedance is not well defined, for example where the source impedance is
subject to unpredictable variations, an impedance having resistance and inductance equal to
the reference impedance may be connected between the supply and the terminals of the
equipment under test. Measurements can then be made of the voltages at the source side of
the reference impedance and at the equipment terminals. In that case, the maximum relative
voltage change, d , measured at the supply terminals shall be less than 20 % of the
max
maximum value d measured at the equipment terminals.

max
NOTE The above method using a voltage source with undefined impedance is not used where the measured
values are close to the limits.
6.3 Test supply voltage
The test supply voltage (open-circuit voltage) shall be the rated voltage of the equipment. If a
voltage range is stipulated for the equipment, the test voltage shall be 230 V single-phase or
400 V three-phase. The test voltage shall be maintained within ± 2 % of the nominal value.
The frequency shall be 50 Hz ± 0,25 Hz.
The percentage total harmonic distortion of the supply voltage shall be less than 3 %.
Fluctuations of the test supply voltage during a test may be neglected if the P value,
st
produced from these fluctuations, is less than 0,4. If the measurements are made directly
using the mains supply, this condition shall be verified before and after each test. If
measurements are made using a controlled power source, this condition shall be verified
during calibration of the power source.
NOTE Frequency deviations can cause the measured P and P values to increase. Also, when testing a flicker
st lt
meter response according to Tables 1b and 2b in IEC 61000-4-15: 2010, the 50 Hz frequency is preferably
controlled to within ± 0,25 Hz.
6.4 Reference impedance
For equipment under test the reference impedance, Z according to IEC/TR 60725, is a
,
ref
conventional impedance used in the calculation and measurement of the directly measured
parameters, and the P and P values.

st lt
© IEC 2017
The impedance values of the various elements are given in Figure 1.
6.5 Observation period
The observation period, T , for the assessment of flicker values by flicker measurement,
p
flicker simulation, or analytical method shall be:
• for P , T = 10 min;
st p
• for P , T = 2 h.
lt p
The observation period shall include that part of the whole operation cycle in which the
equipment under test produces the most unfavourable sequence of voltage changes.
For the assessment of P , the cycle of operation shall be repeated continuously, unless

st
stated otherwise in Annex A. The minimum time to restart the equipment shall be included in
this observation period when testing equipment that stops automatically at the end of a cycle
of operation which lasts for less than the observation period.
For P assessment, the cycle of operation shall not be repeated, unless stated otherwise in

lt
Annex A, when testing equipment with a cycle of operation of less than 2 h and which is not
normally used continuously.
NOTE For example, in the case of equipment with a cycle of operation lasting 45 min, five consecutive P values

st
are measured during a total period of 50 min, and the remaining seven P values in the 2 h observation period are

st
deemed to be zero.
6.6 General test conditions
The test conditions for the measurement of voltage fluctuations and flicker are given below.
For equipment not mentioned in Annex A, controls or automatic programs shall be set to
produce the most unfavourable sequence of voltage changes, using only those combinations
of controls and programmes which are mentioned by the manufacturer in the instruction
manual, or are otherwise likely to be used.
The equipment shall be tested in the condition in which it is supplied by the manufacturer.
Preliminary operation of motor drives may be needed before the tests to ensure that results
corresponding to those of normal use are obtained.
NOTE Operating conditions include mechanical and/or electrical loading conditions.
For moto
...