Amendment 1 - Effects of current on human beings and livestock - Part 1: General aspects

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Replaced
Publication Date
11-Jul-2016
Current Stage
DELPUB - Deleted Publication
Completion Date
13-Dec-2018
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IEC TS 60479-1:2005/AMD1:2016 - Amendment 1 - Effects of current on human beings and livestock - Part 1: General aspects Released:7/12/2016 Isbn:9782832235034
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IEC TS 60479-1 ®
Edition 4.0 2016-07
TECHNICAL
SPECIFICATION
colour
inside
BASIC SAFETY PUBLICATION
AMENDMENT 1
Effects of current on human beings and livestock –
Part 1: General aspects
IEC TS 60479-1:2005-07/AMD1:2016-07(en)

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IEC TS 60479-1 ®
Edition 4.0 2016-07
TECHNICAL
SPECIFICATION
colour
inside
BASIC SAFETY PUBLICATION
AMENDMENT 1
Effects of current on human beings and livestock –

Part 1: General aspects
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.200; 29.020 ISBN 978-2-8322-3503-4

– 2 – IEC TS 60479-1:2005/AMD1:2016

© IEC 2016
FOREWORD
This amendment has been prepared by IEC technical committee 64: Electrical installations

and protection against electric shock.

The text of this amendment is based on the following documents:

Enquiry draft Report on voting

64/2095/DTS 64/2113/RVC
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the stability date indicated on the IEC website 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• withdrawn,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.
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 document using a
colour printer.
_____________
FOREWORD
Add, after the sentence "The main changes with respect to the previous edition are listed
below:" and the existing dashed list items, the following new text:
– Extension of the applicability of the total body impedance to a frequency range up to
150 kHz;
– Clarification of the difference in anodic versus cathodic d.c. pulses;
– Extension of the ventricular fibrillation threshold of single pulses down to 1 µs pulse width;
– Addition of informative annexes:
Annex E: Theories of ventricular fibrillation;
Annex F: Quantities ULV and LLV;
Annex G: Circuit simulation methods in electric shock evaluation.

© IEC 2016
INTRODUCTION
Replace the existing introduction with the following new introduction:

INTRODUCTION
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.
This technical specification provides basic guidance on the effects of shock current on human
beings and livestock, for use in the establishment of electrical safety requirements.
In order to avoid errors in the interpretation of this technical specification, 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.
On the evidence available, mostly from animal research, the values are so conservative that
this document applies to persons of normal physiological conditions including children,
irrespective of age and weight.
There are, however, other aspects to be taken into account, such as probability of faults,
probability of contact with live or faulty parts, ratio between touch voltage and fault voltage,
experience gained, technical feasibilities, and economics. These parameters should be
considered carefully when fixing safety requirements, for example, operating characteristics of
protective devices for electrical installations.
The form of the document as has been adopted summarizes results so far achieved which are
being used by technical committee 64 as a basis for fixing requirements for protection against
shock. These results are considered important enough to justify an IEC publication which may
serve as a guide to other IEC committees and countries having need of such information.
This technical specification applies to the threshold of ventricular fibrillation which is the main
cause of deaths by electric current. The analysis of results of recent research work on cardiac
physiology and on the fibrillation threshold, taken together, has made it possible to better
appreciate the influence of the main physical parameters and, especially, of the duration of
the current flow.
IEC TS 60479-1 contains information about body impedance and body current thresholds for
various physiological effects. This information can be combined to derive estimates of a.c.
and d.c. touch voltage thresholds for certain body current pathways, contact moisture
conditions, and skin contact areas.
This technical specification refers specifically to the effects of electric current. When an
assessment of the harmful effects of any event on human beings and livestock is being made,
other non-electric phenomena, including falls, heat, fire, or others should be taken into
account. These matters are beyond the scope of this technical specification, but may be
extremely serious in their own right.
Further experimental data are under consideration, such as recent ongoing experimental work
on "current induced heart fibrillation by excitation with discrete Fourier spectra" which is
intended to contribute to frequency factor data.

– 4 – IEC TS 60479-1:2005/AMD1:2016

© IEC 2016
4.5.3 Sinusoidal alternating current with frequencies up to 150 kHz

Replace the existing fourth paragraph with the following new text:

Figure 11 shows the frequency dependence of the total body impedance Z for a current path
T
hand to hand and large surface areas of contact for a touch voltage of 25 V and frequencies

from 25 Hz to 150 kHz. From the results, curves have been derived giving the dependence of

the total body impedance Z of a population for the 50th percentile rank for touch voltages
T
from 10 V to 1 000 V and a frequency range from 50 Hz to 150 kHz for a current path hand to
hand or hand to foot for large surface areas of contact in dry condition. The curves are shown

in Figure 12.
5 Effects of sinusoidal alternating current in the range of 15 Hz to 100 Hz
Replace the existing title with the following new title:
5 Effects of sinusoidal alternating current in the range of 15 Hz to 150 kHz
Replace the existing first paragraph with the following new text:
Clause 5 describes the effects of sinusoidal alternating current passing through the human
body within the frequency range 15 Hz to 150 kHz.
6.6 Heart factor
Replace the existing Figure 12 with the following new Figure 12:
150 kHz
6 000
5 000
4 000
10 V AC
3 000
25 V
50 V
2 000
100 V
225 V
1 000 V
1 000
600 Ω
90 100 200 500 1 000 2 000 5 000 10 000 20 000 50 000 100 000
Frequency f, Hz
IEC
Figure 12 – Frequency dependence of the total body impedance Z of
T
a population for a percentile rank of 50 % for touch voltages from 10 V to 1 000 V
and a frequency range from 50 Hz to 150 kHz for a current path hand to hand or
hand to foot, large surface areas of contact in dry conditions

Total body impedance Z , Ω
T
© IEC 2016
Add, at the end of the existing Subclause 6.6 the following new Subclause 6.7:

6.7 Effects of anodic versus cathodic d.c. currents

An electrode is an interface to another medium where charged particles are interchanged.

NOTE Charged particles are to be differentiated, and an anion is a negatively charged particle and a cation is a

positively charged particle.
An anode is an electrode which is at positive potential with respect to a lower potential

reference, such as the positive terminal of a source. Anodic current is current that flows away

from an anode.
A cathode is an electrode which is at negative potential with respect to a higher potential
reference, such as the negative terminal of a source. Cathodic current is current that flows to
a cathode.
To understand that current flow direction plays a role with d.c. pulses, first a simple
explanatory model (Figure 24) is introduced.
The current in this context is conventional current as opposed to electron flow. Current is
applied on a body part with an excitable structure (e.g. a nerve) inside via one small
electrode 1 (called different electrode) and a large area electrode 2 (called indifferent
electrode).
Current distribution is asymmetric with a large current density in area A and a low current
density in area B. See Figure 24.
Electrode 2
Electrode 1
Excitable
structure
(e.g. nerve)
Area A Area B
Body part
IEC
Figure 24 – Effects of anodic versus cathodic d.c. currents

– 6 – IEC TS 60479-1:2005/AMD1:2016

© IEC 2016
Now various d.c. pulses show different behaviour: Responses of the excitable structure arises

in the following order with respect to increasing excitation current depending on polarity and

on either closing or opening the current flow of the circuit:

• cathodal make reaction (CMR);

• anodal make reaction (AMR);
• anodal break reaction (ABR);

• cathodal break reaction (CBR).

This is called the “Law of polar excitation”.

This behaviour can be explained as follows.
The outside of the membrane of the excitable structure becomes more negative in area A
when electrode 1 is the cathode. This results in that the membrane is depolarized because
the internal potential of the cell is also negative: The cell fires, is excited from area A at
closing of the current circuit, a CMR results.
If the polarity is reversed (electrode 1 is now anode) then this same response is again arising
from the cathode, but in this case it has its origin from area B with a lower current density, it is
then called an AMR because the reference is always the small different electrode. The
threshold is higher than for a CMR. This sequence can be reversed (so called anodal dip) for
2+
short pulses of about 180 ms due to a transient Ca ion current.
If the current is flowing after the closure and then opened, an opening response can occur.
The lower threshold for that kind of response occurs again from area A in the anodal case, the
reason for the opening reaction is that the channels responsible are depolarized again
because they were "clamped" before, during the persisted current flow, resulting in an ABR.
The CBR with the highest threshold of all has then its origin from area B.
In principle this behaviour of excitable cells to d.c. pulses always occurs if the current
distribution is asymmetric and the effect is more or less prominent depending on the
difference in size and current flow between the different and indifferent electrode. At least for
pulses delivered within 1 cm of the cardiac surface, cathodal d.c. pulse trains are slightly
safer as they require 25 % more current to induce ventricular fibrillation than anodal pulse
trains [32].
Als
...

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