IEC 60479-2:2019

Effects of current on human beings and livestock - Part 2: Special aspects

IEC 60479-2:2019 describes the effects on the human body when a sinusoidal alternating current in the frequency range above 100 Hz passes through it.
The effects of current passing through the human body for:
– alternating sinusoidal current with DC components,
– alternating sinusoidal current with phase control, and
– alternating sinusoidal current with multicycle control
are given but are only deemed applicable for alternating current frequencies from 15 Hz up to 100 Hz.
Means of extending the frequency of applicability of pure sinusoids to a frequency of 150 kHz are given and means of examining random complex irregular waveforms are given.
This document describes the effects of current passing through the human body in the form of single and multiple successive unidirectional rectangular impulses, sinusoidal impulses and impulses resulting from capacitor discharges. The values specified are deemed to be applicable for impulse durations from 0,1 ms up to and including 10 ms.
This document only considers conducted current resulting from the direct application of a source of current to the body, as does IEC 60479-1. It does not consider current induced within the body caused by its exposure to an external electromagnetic field.
This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. It is not intended for use by manufacturers or certification bodies. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
This first edition cancels and replaces IEC TS 60479-2:2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to IEC TS 60479 2:2017:
a) change in status from Technical Specification to International Standard.

General Information

• Status: Published
• Publication Date: 13-May-2019
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 13.200 - Accident and disaster control
• ICS: 29.020 - Electrical engineering in general
• Technical Committee: TC 64 - Electrical installations and protection against electric shock
• Drafting Committee: MT 4 - TC 64/MT 4
• Current Stage: PPUB - Publication issued
• Start Date: 14-May-2019
• Completion Date: 25-Apr-2019

Relations

• Replaces: IEC TS 60479-2:2017 - Effects of current on human beings and livestock - Part 2: Special aspects
• Effective Date: 05-Sep-2023

Overview - IEC 60479-2:2019 (Effects of current on human beings and livestock - Part 2: Special aspects)

IEC 60479-2:2019 is an IEC International Standard that documents the physiological effects of electrical current when it is conducted directly through the human body. It builds on IEC 60479-1 by addressing special waveforms, frequency ranges and impulse conditions. This edition (first as an International Standard) cancels IEC TS 60479-2:2017 and provides revised guidance for technical committees preparing safety standards.

Key topics and technical coverage

• Frequency scope
  • Primary focus: sinusoidal alternating current with frequencies above 100 Hz.
  • Special treatments (AC with DC components, phase control, multicycle control) are given for 15 Hz to 100 Hz.
  • Methods to extend applicability of pure sinusoids up to 150 kHz are provided.
• Waveforms and impulses
  • Analysis of sinusoidal impulses, unidirectional rectangular impulses and capacitor-discharge impulses for durations 0.1 ms to 10 ms.
  • Guidance for random complex irregular waveforms (Annex A) and pulse bursts.
• Physiological thresholds and effects
  • Quantified and discussed thresholds for perception, let‑go, startle reaction, and ventricular fibrillation across frequencies and waveform types.
  • Procedures to estimate equivalent current thresholds for mixed-frequency and burst conditions.
• Special conditions
  • Conducted current due to direct contact only - the document does not treat currents induced by external electromagnetic fields.
  • Effects of current through an immersed human body, including resistivity data and intrinsically safe voltage considerations.
• Data and tools
  • Figures and tables offering empirical threshold curves, waveform examples, and resistivity values to support risk assessment and standard drafting.

Practical applications - who uses IEC 60479-2:2019

• Technical committees and standards writers (primary audience) using this basic safety publication when developing or revising electrotechnical safety standards in line with IEC Guide 104 and ISO/IEC Guide 51.
• Safety researchers, biomedical engineers and laboratory investigators analyzing current–body interactions for medical devices, electrical safety studies and experimental design.
• Regulators and policy makers referencing physiological thresholds for public safety guidance (note: the publication is not intended as a direct certification or manufacturing standard unless explicitly referenced).

Related standards and guidance

• IEC 60479-1 (general principles on effects of current on human beings and livestock) - complementary core document.
• IEC Guide 104 and ISO/IEC Guide 51 - principles for using basic safety publications in standards development.

Keywords: IEC 60479-2:2019, effects of current on human beings, alternating current frequency, ventricular fibrillation threshold, let‑go threshold, impulse currents, capacitor discharge, phase control, multicycle control, random complex waveforms, electrical safety standard.

Standards Content (Sample)

IEC 60479-2 ®
Edition 1.0 2019-05
INTERNATIONAL
STANDARD
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BASIC SAFETY PUBLICATION
Effects of current on human beings and livestock –
Part 2: Special aspects
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IEC 60479-2 ®
Edition 1.0 2019-05
INTERNATIONAL
STANDARD
colour
inside
BASIC SAFETY PUBLICATION
Effects of current on human beings and livestock –

Part 2: Special aspects
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.200; 29.020 ISBN 978-2-8322-6689-2

– 2 – IEC 60479-2:2019 © IEC 2019
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Effects of alternating currents with frequencies above 100 Hz . 11
4.1 General . 11
4.2 Effects of alternating current in the frequency range above 100 Hz up to and
including 1 000 Hz . 12
4.2.1 Threshold of perception . 12
4.2.2 Threshold of let-go . 12
4.2.3 Threshold of ventricular fibrillation . 13
4.3 Effects of alternating current in the frequency range above 1 000 Hz up to
and including 10 000 Hz . 14
4.3.1 Threshold of perception . 14
4.3.2 Threshold of let-go . 14
4.3.3 Threshold of ventricular fibrillation . 15
4.4 Effects of alternating current in the frequency range above 10 000 Hz . 15
4.4.1 General . 15
4.4.2 Threshold of perception . 15
4.4.3 Threshold of let-go . 15
4.4.4 Threshold of ventricular fibrillation . 15
4.4.5 Other effects . 16
5 Effects of special waveforms of current . 16
5.1 General . 16
5.2 Equivalent magnitude, frequency and threshold . 16
5.3 Effects of alternating current with DC components . 17
5.3.1 Waveforms and frequencies and current thresholds . 17
5.3.2 Threshold of startle reaction . 18
5.3.3 Threshold of let-go . 19
5.3.4 Threshold of ventricular fibrillation . 20
6 Effects of alternating current with phase control . 24
6.1 Waveforms and frequencies and current thresholds . 24
6.2 Threshold of startle reaction and threshold of let-go . 25
6.3 Threshold of ventricular fibrillation . 25
6.3.1 General . 25
6.3.2 Symmetrical control . 26
6.3.3 Asymmetrical control . 26
7 Effects of alternating current with multicyle control . 26
7.1 Waveforms and frequencies . 26
7.2 Threshold of startle reaction and threshold of let-go . 27
7.3 Threshold of ventricular fibrillation . 27
7.3.1 General . 27
7.3.2 Shock durations longer than 1,5 times the period of the cardiac cycle . 28
7.3.3 Shock durations less than 0,75 times the period of the cardiac cycle . 28

8 Estimation of the equivalent current threshold for mixed frequencies . 28
8.1 Threshold of perception and let-go . 28
8.2 Threshold of ventricular fibrillation . 29
9 Effects of current pulse bursts and random complex irregular waveforms . 29
9.1 Ventricular fibrillation threshold of multiple pulses of current separated by
300 ms or more . 29
9.2 Ventricular fibrillation threshold of multiple pulses of current separated by
than 300 ms . 29
less
9.2.1 General . 29
9.2.2 Examples. 30
9.2.3 Random complex irregular waveforms . 32
10 Effects of electric current through the immersed human body . 34
10.1 General . 34
10.2 Resistivity of water solutions and of the human body . 34
10.3 Conducted current through immersed body . 36
10.4 Physiological effects of current through the immersed body . 37
10.5 Threshold values of current . 38
10.6 Intrinsically “safe” voltage values . 38
11 Effects of unidirectional single impulse currents of short duration . 38
11.1 General . 38
11.2 Effects of unidirectional impulse currents of short duration . 39
11.2.1 Waveforms . 39
11.2.2 Determination of specific fibrillating energy F . 40
e
11.3 Threshold of perception and threshold of pain for capacitor discharge . 41
11.4 Threshold of ventricular fibrillation . 43
11.4.1 General . 43
11.4.2 Examples. 44
Annex A (informative) Random complex irregular waveform analysis . 47
A.1 General . 47
A.2 Formal theoretical statement of the method . 47
A.3 Demonstration of the calculation . 48
A.3.1 General . 48
A.3.2 Choice of justified current . 50
A.3.3 Choice of sampling step size . 50
A.4 Examples 1 and 2 . 51
Bibliography . 54

Figure 1 – Variation of the threshold of perception within the frequency range
50/60 Hz to 1 000 Hz . 12
Figure 2 – Variation of the threshold of let-go within the frequency range 50/60 Hz to
1 000 Hz . 13
Figure 3 – Variation of the threshold of ventricular fibrillation within the frequency
range 50/60 Hz to 1 000 Hz, shock durations longer than one heart period and
longitudinal current paths through the trunk of the body . 13
Figure 4 – Variation of the threshold of perception within the frequency range

1 000 Hz to 10 000 Hz . 14
Figure 5 – Variation of the threshold of let-go within the frequency range 1 000 Hz to
10 000 Hz . 14

– 4 – IEC 60479-2:2019 © IEC 2019
Figure 6 – Variation of the threshold of ventricular fibrillation for continuous sinusoidal
current (1 000 Hz to 150 kHz) . 16
Figure 7 – Waveforms of currents . 18
Figure 8 – Let-go thresholds for men, women and children . 19
Figure 9 – 99,5-percentile let-go threshold for combinations of 50/60 Hz sinusoidal

alternating current and direct current . 20
Figure 10 – Composite alternating and direct current with equivalent likelihood of
ventricular fibrillation. 22
Figure 11 – Waveforms of rectified alternating currents . 23
Figure 12 – Waveforms of alternating currents with phase control . 25
Figure 13 – Waveforms of alternating currents calculated with multicycle control factor . 27
Figure 14 – Threshold of ventricular fibrillation (average value) for alternating current
with multicycle control for various degrees of controls (results of experiments with

young pigs) . 28
Figure 15 – Series of four rectangular pulses of unidirectional current . 31
Figure 16 – Series of four rectangular pulses of unidirectional current . 31
Figure 17 – Series of four rectangular pulses of unidirectional current . 32
Figure 18 – Example of current versus elapsed time over a contaminated insulator . 33
Figure 19 – PC plotted on the AC time current curves (IEC 60479-1:2018, Figure 20). 34
Figure 20 – Forms of current for rectangular impulses, sinusoidal impulses and for
capacitor discharges . 40
Figure 21 – Rectangular impulse, sinusoidal impulse and capacitor discharge having
the same specific fibrillating energy and the same shock duration. 41
Figure 22 – Threshold of perception and threshold of pain for the current resulting
from the discharge of a capacitor (dry hands, large contact area) . 42
Figure 23 – Probability of fibrillation risks for current flowing in the path left hand to
feet . 44
Figure A.1 – Definition of a segment of a random complex waveform . 47
Figure A.2 – Definition of a duration within a sample . 47
Figure A.3 – PC for demonstration example of the random complex waveform method
plotted against time-current curves for RMS AC . 50
Figure A.4 – Random complex waveform typical of those used in Example 1 . 51
Figure A.5 – Random complex waveform typical of those used in Example 2 . 52
Figure A.6 – PC for Examples 1 and 2 of the random complex waveform method
plotted against time-current curves for RMS AC . 53

Table 1 – Estimate for ventricular fibrillation threshold after each pulse of current in a
series of pulses each of which excited the heart tissue in such a manner as to trigger
ventricular responses . 30
Table 2 – Resistivity of water solutions [24], [25] . 35
Table 3 – Resistivity of human body tissues . 36
Table 4 – Relative interaction between the resistivity of water solution and the
impedance characteristic of the electrical source . 37
Table 5 – Effects of shocks . 45
Table 6 – Effects of shocks . 46

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EFFECTS OF CURRENT ON HUMAN BEINGS AND LIVESTOCK –

Part 2: Special aspects
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
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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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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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 60479-2 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
This first edition cancels and replaces IEC TS 60479-2:2017. This edition constitutes a
technical revision.
This edition includes the following significant technical changes with respect to
IEC TS 60479-2:2017:
a) change in status from Technical Specification to International Standard.
It has the status of a basic safety publication in accordance with IEC Guide 104.

– 6 – IEC 60479-2:2019 © IEC 2019
The text of this International Standard is based on the following documents:
CDV Report on voting
64/2300/CDV 64/2362/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60479 series, published under the general title Effects of current
on human beings and livestock, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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 publication using a colour printer.

INTRODUCTION
In order to avoid errors in the interpretation of this document, it should be emphasized that
the data given herein is mainly based on experiments with animals as well as on information
available from clinical observations. Only a few experiments with shock currents of short
duration have been carried out on living human beings.
The effects of current passing through the human body for
– alternating sinusoidal current with DC components,
– alternating sinusoidal current with phase control,
– alternating sinusoidal current with multicycle control,
– equivalent current threshold for mixed frequencies,
– current pulse bursts and random complex irregular waveforms,
– electric current through the immersed human body, and
– unidirectional single impulse currents of short duration
are described.
– 8 – IEC 60479-2:2019 © IEC 2019
EFFECTS OF CURRENT ON HUMAN BEINGS AND LIVESTOCK –

Part 2: Special aspects
1 Scope
This part of IEC 60479 describes the effects on the human body when a sinusoidal
alternating current in the frequency range above 100 Hz passes through it.
The effects of current passing through the human body for:
– alternating sinusoidal current with DC components,
– alternating sinusoidal current with phase control, and
– alternating sinusoidal current with multicycle control
are given but are only deemed applicable for alternating current frequencies
from 15 Hz up to 100 Hz.
Means of extending the frequency of applicability of pure sinusoids to a frequency of 150 kHz
are given, supplementing the data in IEC 60479-1.
Means of examining random complex irregular waveforms are given.
This document describes the effects of current passing through the human body in the form of
single and multiple successive unidirectional rectangular impulses, sinusoidal impulses and
impulses resulting from capacitor discharges.
The values specified are deemed to be applicable for impulse durations from 0,1 ms up to and
including 10 ms.
This document only considers conducted current resulting from the direct application of a
source of current to the body, as does IEC 60479-1. It does not consider current induced
within the body caused by its exposure to an external electromagnetic field.
This basic safety publication is primarily intended for use by technical committees in the
preparation of standards in accordance with the principles laid down in IEC Guide 104 and
ISO/IEC Guide 51. It is not intended for use by manufacturers or certification bodies.
One of the responsibilities of a technical committee is, wherever applicable, to make use of
basic safety publications in the preparation of its publications. The requirements, test
methods or test conditions of this basic safety publication will not apply unless specifically
referred to or included in the relevant publications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60479-1:2018, Effects of current on human beings and livestock – Part 1: General
aspects
IEC 60990, Methods of measurement of touch-current and protective conductor current
IEC Guide 104, The preparation of safety publications and the use of basic safety publications
and group safety publications
ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60479-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
frequency factor
F
f
ratio of the threshold current for the relevant physiological effects at the frequency f to the
threshold current at 50/60 Hz.
Note 1 to entry: The frequency factor differs for perception, let-go and ventricular fibrillation.
3.2
phase control
process of varying the instant within the cycle at which current conduction in an electronic
valve device or a valve arm begins
[SOURCE: IEC 60050-551:1998, 551-16-23]
3.3
phase control angle
current delay angle
time expressed in angular measure by which the starting instant of current conduction is
delayed by phase control
[SOURCE: IEC 60050-551:1998, 551-16-32, modified — The term "phase control angle" has
been added.]
3.4
multicycle control
process of varying the ratio of the number of cycles which include current conduction to the
number of cycles in which no current conduction occurs
[SOURCE: IEC 60050-551:1998, 551-16-31]
3.5
multicycle control factor
p
ratio between the number of conducting cycles and the sum of conducting and non-conducting
cycles in the case of multicycle control
SEE Figure 13.
– 10 – IEC 60479-2:2019 © IEC 2019
[SOURCE: IEC 60050-551:1998, 551-16-37, modified — The symbol and reference to
Figure 13 have been added.]
3.6
specific fibrillating energy
F
e
·t value of a unidirectional impulse of short duration which under given conditions
minimum I
(current-path, heart-phase) causes ventricular fibrillation with a certain probability
Note 1 to entry: F is determined by the form of the impulse as the integral
e
t
i 2
i dt
∫
where t is defined in Figure 20 and Figure 21. F multiplied by the body resistance gives the energy dissipated in
i e
the human body during the impulse.
Note 2 to entry: F is expressed in Ws/Ω or A s.
e
3.7
specific fibrillating charge
F
q
minimum I·t value of unidirectional impulse of short duration which under given conditions
(current-path, heart-phase) causes ventricular fibrillation with a certain probability
Note 1 to entry: F is determined by the form of the impulse as the integral
q
t
i
idt
∫
where t is defined in Figure 20 and Figure 21.
i
Note 2 to entry: F is expressed in C or As.
q
3.8
time constant
time required for the amplitude of an exponentially decaying quantity to decrease to
= 0,367 9
e
times an initial amplitude
[SOURCE: IEC 60050-801:1994, 801-21-45, modified — The definition has been revised.]
3.9
shock duration
t
i
time interval from the beginning of the discharge to the time when
the discharge current has fallen to 5 % of its peak value
Note 1 to entry: When the time constant of the capacitor discharge is given by T the shock duration of the
capacitor discharge is equal to 3T. During the shock duration of the capacitor discharge practically all the energy of
the impulse is dissipated.
Note 2 to entry: See Figure 20 and Figure 21.
3.10
shock duration
t
i
shortest duration of that part of the impulse that contains
95 % of the energy over the total impulse

3.11
threshold of perception
minimum value for the charge of electricity, which, under given conditions, causes any
sensation to the person through whom it is flowing
3.12
threshold of pain
2⋅
minimum value for the charge (I∙t) or specific energy (I t) that can be applied as an impulse
to a person holding a large electrode in the hand without causing pain
3.13
pain
unpleasant experience such that it is not readily accepted a second time by the subject
submitted to it
EXAMPLE: Electric shock above the threshold of pain described in 11.3, the sting of a bee or the burn of a
cigarette.
4 Effects of alternating currents with frequencies above 100 Hz
NOTE Values for 50/60 Hz are given in IEC 60479-1. For frequencies up to 100 Hz the provisions of IEC 60479-1
are used.
4.1 General
Electric energy in the form of alternating current at frequencies higher than 50/60 Hz is
increasingly used in modern electrical equipment, for example aircraft (400 Hz), power tools
and electric welding (mostly up to 450 Hz), electrotherapy (using mostly 4 000 Hz to
5 000 Hz) and switching mode power supplies (20 kHz to 1 MHz).
Little experimental data is available for Clause 4, therefore the information given herein
should be considered as provisional only but may be used for the evaluation of risks in the
frequency ranges concerned (see Bibliography).
Recent experiments in government-funded projects are ongoing to exploit and investigate the
effects of higher frequencies using the latest technologies and methods to justify existing
extrapolation of the frequency factor for ventricular fibrillation (VF) threshold.
Attention is also drawn to the fact that the impedance of human skin decreases
approximately inversely proportional to the frequency for touch voltages in the order of
some tens of volts, so that the skin impedance at 500 Hz is only about one-tenth of the skin
impedance at 50 Hz and may be neglected in many cases. This impedance of the human
body at such frequencies is therefore reduced to its internal impedance Z (see
i
IEC 60479-1).
NOTE Use of peak measurements: at current levels that produce physiological responses of perception,
startle reaction and inability of let-go, the physiological response from non-sinusoidal and mixed-frequency
periodic current is best indicated by the peak value of an output signal from measuring circuits containing a
frequency-weighting network such as those described in IEC 60990.
These frequency-weighting networks attenuate the signal according to the frequency factors
given in IEC 60479-1:2018, Clause 4 so that the output signal corresponds to a constant
level of physiological response. Attenuation is provided for narrow impulses of current that
would produce less physiological response because of the short duration of their peak value.
The network output allows a fixed value to be read independently of waveshape or mix of
frequencies to be provided for ease of determination of the leakage current and evaluation of
the level of hazard present.
Comparable physiological effects are produced by non-sinusoidal and sinusoidal currents
producing the same peak values by this measurement method.

– 12 – IEC 60479-2:2019 © IEC 2019
A representative network can be found in IEC 60990 and in [16] .
4.2 Effects of alternating current in the frequency range above 100 Hz up to and
including 1 000 Hz
4.2.1 Threshold of perception
For the threshold of perception, the frequency factor is given in Figure 1.

Figure 1 – Variation of the threshold of perception
within the frequency range 50/60 Hz to 1 000 Hz
4.2.2 Threshold of let-go
For the threshold of let-go, the frequency factor is given in Figure 2.
___________
Numbers in square brackets refer to the Bibliography.

Figure 2 – Variation of the threshold of let-go
within the frequency range 50/60 Hz to 1 000 Hz
4.2.3 Threshold of ventricular fibrillation
For shock durations longer than the cardiac cycle, the frequency factor for the threshold of
fibrillation for longitudinal current paths through the trunk of the body is given in Figure 3.
For shock durations shorter than the cardiac cycle, no experimental data is available on the
effects of frequency.
Figure 3 – Variation of the threshold of ventricular fibrillation within the frequency
range 50/60 Hz to 1 000 Hz, shock durations longer than one heart period and
longitudinal current paths through the trunk of the body

– 14 – IEC 60479-2:2019 © IEC 2019
4.3 Effects of alternating current in the frequency range above 1 000 Hz up to and
including 10 000 Hz
4.3.1 Threshold of perception
For the threshold of perception, the frequency factor is given in Figure 4.

Figure 4 – Variation of the threshold of perception
within the frequency range 1 000 Hz to 10 000 Hz
4.3.2 Threshold of let-go
For the threshold of let-go, the frequency factor is given in Figure 5.

Figure 5 – Variation of the threshold of let-go
within the frequency range 1 000 Hz to 10 000 Hz

4.3.3 Threshold of ventricular fibrillation
For frequencies between 1 000 Hz and 10 000 Hz, the provisions of 4.4.4 are used.
4.4 Effects of alternating current in the frequency range above 10 000 Hz
4.4.1 General
In 4.4, changes have not been made to the values of the threshold of perception, or the
threshold of let-go for higher frequencies. While these are important thresholds, the most
dangerous is that of ventricular fibrillation. The fibrillation threshold is therefore given up to
150 kHz. The remaining thresholds may be considered as in the paragraphs below up to the
frequency limits shown.
4.4.2 Threshold of perception
For frequencies between 10 kHz and 100 kHz, the threshold rises approximately from 10 mA
to 100 mA (RMS values).
For frequencies above 100 kHz, the tingling sensation characteristic for the perception at
lower frequencies changes into a sensation of warmth for current intensities in the order of
some hundred mill amperes.
4.4.3 Threshold of let-go
For frequencies above 100 kHz, there is neither experimental data nor reported incidents
concerning the threshold of let-go.
4.4.4 Threshold of ventricular fibrillation
For shock durations longer than the cardiac cycle, the frequency factor for the threshold of
fibrillation for longitudinal current paths through the trunk of the body for the frequency range
above 1 000 Hz up to and including 150 kHz is given in Figure 6.
For frequencies above 1 kHz, thermal effects are more likely to become dominant.
For shock durations shorter than the cardiac cycle, no experimental data is available.

– 16 – IEC 60479-2:2019 © IEC 2019

Figure 6 – Variation of the threshold of ventricular fibrillation for
continuous sinusoidal current (1 000 Hz to 150 kHz)
4.4.5 Other effects
Burns may occur at frequencies above 100 kHz and current magnitudes in the order of
amperes depending on the duration of the current flow.
5 Effects of special waveforms of current
5.1 General
As is to be expected, the effects of such currents on the human body are between those
caused by direct and by alternating current; therefore, equivalent current magnitudes with
regard to ventricular fibrillation can be established.
Clause 5 describes the effects of current passing through the human body for:
– alternating sinusoidal current with DC components,
– alternating sinusoidal current with phase control,
– alternating sinusoidal current with multicycle control.
NOTE Other waveforms are under consideration.
The information given is deemed applicable for alternating current frequencies from 15 Hz up
to 100 Hz.
5.2 Equivalent magnitude, frequency and threshold
In 5.2, the hazard may be taken as having approximately the same effect as with an
equivalent pure alternating sinusoidal current I having the following characteristics:
ev
– Magnitude equivalence:
The following current magnitudes have to be distinguished:
I = RMS value of the current of the proposed waveform,
RMS
I = peak value of the current of the proposed waveform,
p
I = peak-to-peak value of the current of the proposed waveform,
pp
I = RMS value of a sinusoidal current presenting the same effect as
ev
the waveform concerned.
NOTE The current I is used instead of the current I given in IEC 60479-1:2018, Figure 20 and Figure 22 to
ev B
estimate the risk of ventricular fibrillation.
Most physiological effects are related to the filtered peak current (in magnitude and in
duration) with the natural body filter defined by the frequency factor F. The peak value of
the current should be used in all cases except where there is a known relationship
between the RMS value and the peak value, i.e. pure sinusoidal current.
– Frequency equivalence
The waveform under study has a time period equal to the period of the equivalent
sinusoidal waveform.
– Threshold equivalence
The different current thresholds (perception, inability of let-go and ventricular fibrillation)
for waveforms consisting of specific ratios of alternating to direct current are equivalent to
a pure sinusoidal alternating current with a current having the characteristic equal to I .
ev
This I value is different for each of these thresholds.
ev
5.3 Effects of alternating current with DC components
5.3.1 Waveforms and frequencies and current thresholds
Figure 7 shows typical waveforms, which are dealt with in 5.3.1. Pure DC and pure AC are
represented as well as combined waveforms of various AC to DC ratios.

– 18 – IEC 60479-2:2019 © IEC 2019

a) Combined waveforms of various AC to DC ratios together with rectangle pulse
for shock duration >1,5 and <0,75 of the cardiac cycle

b) Combined waveforms of various AC to DC ratios of mixed frequencies
for shock duration >1,5 and <0,75 of the cardiac cycle
Figure 7 – Waveforms of currents
5.3.2 Threshold of startle reaction
The threshold of startle reaction depends on several parameters such as the area of the body
in contact with an electrode (contact area), the conditions of contact (dry, wet, pressure,
temperature), and also on the physiological characteristics of the individual.
These effects are related to the peak value of the current [13] and the currents have to be
combined frequency by frequency to estimate the total effect. A measurement circuit is
described in IEC 60990.
5.3.3 Threshold of let-go
The threshold of let-go depends on several parameters, such as the contact area, the shape
and the size of the electrodes, and also on the physiological characteristics of the individual.
From the standpoint of let-go (hand contacts with energized circuitry that can last a few
seconds), this document uses Figure 5 in the referenced Dalziel paper [17] to determine the
let-go current threshold for combinations of alternating current and direct current. The
frequency of the alternating current in this case was 60 Hz. A value of 7,07 mA peak AC
(5 mA RMS for a sinusoidal current) and 30 mA DC were used as the touch current thresholds
for pure AC and DC respectively. These thresholds are considered to be adequate to
represent the entire population (including children) from inability to let go.
The equation, I = 7,176 × exp (−0,143 4 × DC) − 0,106 1, represents this combined AC
AC peak
and DC case and may be used to calculate the result of any combination of AC and DC in the
range specified.
The following Figure 8 illustrates the information given by Dalziel.

Figure 8 – Let-go thresholds for men, women and children
The above curves can be described by an equation fitted to the data.
The equation, I = 12,890 5 × exp (−0,069 39 × DC) − 0,190 5, represents the 99,5-
AC peak
percentile curve for men.
The equation, I = 8,523 × exp (−0,104 9 × DC) − 0,126, represents the 99,5-percentile
AC peak
curve for women.
The equation, I = 6,394 5 × exp (−0,138 8 × DC) − 0,094 5, represents the 99,5-
AC peak
percentile estimated curve for children.
For practical considerations, some standards allow for some ripple (e.g. up to 10 %) on a DC
supply as an exception.
Figure 9 shows the let-go threshold expressed in peak mA for combinations of 50/60 Hz
sinusoidal alternating current and direct current. The peak of the composite AC and DC wave

– 20 – IEC 60479-2:2019 © IEC 2019
in mA at the let-go threshold estimated for the population of humans, including children, is
shown as a function of the direct current component in mA.
Figure 9 is represented by the equation for the composite current:
I + I = 7,176 × exp (−0,143 4 × DC) − 0,106 1 + DC
AC peak DC
Figure 9 – 99,5-percentile let-go threshold for combinations
of 50/60 Hz sinusoidal alternating current and direct c
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