EN 60990:2016

Methods of measurement of touch current and protective conductor current

IEC 60990:2016 is available as IEC 60990:2016 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60990:2016 defines measurement methods for d.c. or a.c. current of sinusoidal or non-sinusoidal waveform, which could flow through the human body, and current flowing through a protective conductor. The measuring methods recommended for TOUCH CURRENT are based upon the possible effects of current flowing through a human body. In this standard, measurements of current through networks representing the impedance of the human body are referred to as measurements of TOUCH CURRENT. These networks are not necessarily valid for the bodies of animals. The specification or implication of specific limit values is not within the scope of this standard. IEC TS 60479 series provides information regarding the effects of current passing through the human body from which limit values may be derived. This standard is applicable to all classes of EQUIPMENT, according to IEC 61140. The methods of measurement in this standard are not intended to be used for TOUCH CURRENTS having less than 1 s duration, patient currents as defined in IEC 60601-1, a.c. at frequencies below 15 Hz, and currents above those chosen for ELECTRIC BURN limits. This third edition cancels and replaces the second edition published in 1999. It constitutes a technical revision. The principal changes in this edition as compared with the second edition are as follows: - the effects names have been updated to reflect increased understanding of the range of effects and is in concert with present usage; - the conditions of use invoking a GRIPPABLE PART have been reduced in the application of the requirements based upon the current understanding of this effect; - the references to ISO 10012-1, which has been replaced by management standard of the same number, have been replaced with explanatory text, where needed to maintain the sense of the document; - former informative Annex H (GRIPPABLE PART) has been deleted from this update as it does not properly represent the full set of conditions under which immobilization can occur. A new informative Annex H (Analysis of frequency filtered touch current circuits measurement) has been added and the Bibliography (formerly Annex M) has been updated with additional references for completeness. 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 independent of product standards. Key words: Touch Current, Protective Conductor Current, Current Flow

Verfahren zur Messung von Berührungsstrom und Schutzleiterstrom

Méthodes de mesure du courant de contact et du courant dans le conducteur de protection

L'IEC 60990:2016 définit des méthodes de mesure pour les courants continus ou les courants alternatifs de forme d'onde sinusoïdale ou non sinusoïdale qui peuvent traverser le corps humain, et les courants qui peuvent circuler dans un conducteur de protection. Les méthodes de mesure recommandées pour le COURANT DE CONTACT sont basées sur les effets possibles provoqués par le passage du courant dans le corps humain. Dans la présente norme, les mesurages de courant à travers des réseaux représentant l'impédance du corps humain sont appelés mesurages du COURANT DE CONTACT. Les réseaux utilisés ne sont pas nécessairement valables pour des animaux. La spécification ou l'implication de valeurs limites spécifiques ne fait pas partie du domaine d'application de la présente norme. La série IEC TS 60479 fournit des informations concernant les effets du courant traversant le corps humain, à partir desquelles des valeurs limites peuvent être déduites. La présente norme est applicable à toutes les classes de MATERIELS, conformément à l'IEC 61140. Les méthodes de mesure indiquées dans la présente norme ne sont pas destinées à être utilisées pour les COURANTS DE CONTACT de durée inférieure à 1 s, les courants patients tels qu'ils sont définis dans l'IEC 60601-1, les courants alternatifs de fréquence inférieure à 15 Hz, et les courants supérieurs aux courants choisis pour les limites de BRULURE ELECTRIQUE. Cette troisième édition annule et remplace la deuxième édition, parue en 1999. Cette édition constitue une révision technique. Cette édition inclut les modifications majeures suivantes par rapport à la deuxième édition: - les désignations des effets ont été mises à jour pour refléter la meilleure compréhension de la plage des effets et s'accorder avec l'utilisation actuelle; - les conditions d'utilisation impliquant une PARTIE PREHENSIBLE ont été réduites pour l'application des exigences fondées sur la compréhension actuelle de cet effet; - les références à l'ISO 10012-1, qui a été remplacée par une norme de management portant le même numéro, ont été remplacées par un texte explicatif, le cas échéant, afin de conserver le sens du document; - l'ancienne Annexe H informative (PARTIE PREHENSIBLE) a été supprimée de cette mise à jour car elle ne représente pas de manière adéquate l'intégralité des conditions dans lesquelles une immobilisation est susceptible de se produire. Une nouvelle Annexe H informative (Analyse du mesurage de circuits de courant de contact avec filtre de fréquence) a été ajoutée et la Bibliographie (anciennement dénommée Annexe M) a été mise à jour avec des références supplémentaires par souci d'exhaustivité. La présente publication fondamentale de sécurité est destinée principalement à être utilisée par les comités d'études lors de la préparation de normes conformément aux principes figurant dans le Guide IEC 104 et le Guide ISO/IEC 51. Elle n'est pas destinée à être utilisée par les fabricants ou les organismes de certification indépendants de normes de produit. Mots-clés: courant de contact, courant dans le conducteur de protection, passage du courant

Metode merjenja toka dotika in toka v zaščitnem vodniku

Ta mednarodni standard opredeljuje metode merjenja za:
– enosmerni ali izmenični tok sinusoidne ali nesinusoidne valovne oblike, ki lahko teče skozi človeško telo, in
– tok, ki teče skozi zaščitni vodnik.
Metode, priporočene za merjenje TOKA DOTIKA, temeljijo na možnih učinkih toka, ki teče skozi človeško telo. Meritve toka v omrežjih, ki predstavljajo impedanco človeškega telesa, se v tem standardu imenujejo meritve TOKA DOTIKA. Ta omrežja ne veljajo nujno za živalska telesa.
Specifikacija ali vpliv določenih mejnih vrednosti nista zajeta v tem standardu.
Skupina standardov IEC TS 60479 vsebuje informacije v zvezi z učinki toka, ki teče skozi človeško telo, na podlagi katerih je mogoče izračunati mejne vrednosti.
V skladu s standardom IEC 61140 se ta standard uporablja za vse razrede OPREME.
Metode merjenja v tem standardu niso namenjene za uporabo za:
– TOKE DOTIKA, ki trajajo manj kot 1 s,
– tokove bolnikov, kot so opredeljeni v standardu IEC 60601-1,
– izmenični tok s frekvencami, nižjimi od 15 Hz, in
– tokove z vrednostmi nad mejnimi vrednostmi za ELEKTRIČNE OPEKLINE.
Ta osnovna varnostna publikacija je namenjena predvsem tehničnim odborom za pripravo standardov v skladu z načeli vodil IEC 104 in ISO/IEC 51. Ni namenjena proizvajalcem ali certifikacijskim organom, ki so neodvisni od standardov za proizvode.
Ena od pristojnosti tehničnih odborov je, da med pripravo publikacij uporabljajo osnovne varnostne publikacije, kadar je to primerno. Zahteve, preskusne metode ali preskusni pogoji iz te osnovne varnostne publikacije se uporabljajo le, če so izrecno navedeni ali zajeti v ustreznih publikacijah.

General Information

• Status: Published
• Publication Date: 01-Sep-2016
• Withdrawal Date: 03-Jul-2019
• ICS: 17.220 - Electricity. Magnetism. Electrical and magnetic measurements
• ICS: 35.020 - Information technology (IT) in general
• Technical Committee: CLC/TC 108X - Safety of electronic equipment within the fields of Audio/Video, Information Technology and Communication Technology
• Drafting Committee: IEC/TC 108 - IEC_TC_108
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 02-Sep-2016
• Completion Date: 02-Sep-2016
• Ref Project: SIST EN 60990:2017 - Methods of measurement of touch current and protective conductor current

Relations

• Replaces: EN 60990:1999 - Methods of measurement of touch current and protective conductor current
• Effective Date: 27-Jan-2023

Overview

EN 60990:2016 (IEC 60990:2016) - published by CLC/CENELEC - defines standardized methods of measurement of touch current and protective conductor current. It specifies how to measure d.c. and a.c. currents (sinusoidal or non‑sinusoidal) that could flow through the human body or a protective conductor, using measuring networks that represent human body impedance. The standard applies to all classes of equipment per IEC 61140 and is the 3rd edition (technical revision) replacing EN 60990:1999. It does not set limit values; IEC TS 60479 provides guidance on biological effects from which limits may be derived.

Key Topics and Requirements

• Measuring networks: defined networks for unweighted touch current and frequency‑weighted networks for perception / startle‑reaction and let‑go (immobilization) effects. These networks simulate human body impedance for touch current testing.
• Test site and equipment: environmental conditions, test transformers, earthed neutral arrangements, test electrodes and connections, and instrument configuration.
• Measurement procedures: normal and fault conditions, use of measuring networks, supply voltage and frequency considerations, and methods for testing single‑ and three‑phase equipment across TN, TT and IT systems.
• Protective conductor current: procedures for measurement including multiple‑equipment configurations and recommended measuring arrangements.
• Calibration and performance: network/instrument performance, calibration methods, confirmation systems and record‑keeping requirements.
• Scope limitations: excludes touch currents shorter than 1 s, patient currents (IEC 60601‑1), a.c. frequencies below 15 Hz, and currents exceeding electric‑burn ranges. Networks model human bodies, not animals.
• Notable updates (3rd edition):
  • Updated effect terminology and reduced conditions invoking a grippable part
  • Replacement of references to ISO 10012‑1 with explanatory text
  • Deletion of the former Annex H (grippable part) and addition of a new informative Annex H on frequency‑filtered touch current analysis
  • Updated bibliography

Applications and Who Uses It

• Standards and technical committees: primary audience - to prepare product safety standards consistent with IEC Guide 104 and ISO/IEC Guide 51.
• Test laboratories and calibration houses: implement measurement procedures and confirmation systems for touch current and protective conductor current testing.
• Safety and compliance engineers: design validation, risk assessment and verification of electrical products against product‑specific limits (from product standards).
• Manufacturers and product developers: use methods when referenced in product standards for routine tests, after repair/modification, and during design verification (note: EN 60990 itself does not set pass/fail limits).

Related Standards

• IEC TS 60479 series (effects of current on humans and livestock)
• IEC 61140 (protection against electric shock)
• IEC 60601‑1 (medical electrical equipment - patient currents)
• IEC Guide 104, ISO/IEC Guide 51 (safety publication principles)

Keywords: Touch Current, Protective Conductor Current, measurement methods, IEC 60990, EN 60990:2016, measuring networks, let‑go, startle‑reaction, perception, protective conductor measurement.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Methods of measurement of touch current and protective conductor current17.220.20Measurement of electrical and magnetic quantities13.260Protection against electric shock. Live workingICS:Ta slovenski standard je istoveten z:EN 60990:2016SIST EN 60990:2017en01-februar-2017SIST EN 60990:2017SLOVENSKI
STANDARDSIST EN 60990:20021DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 60990
September 2016 ICS 17.220; 35.020
Supersedes
EN 60990:1999
English Version
Methods of measurement of touch current and protective conductor current (IEC 60990:2016)
Méthodes de mesure du courant de contact et
du courant dans le conducteur de protection (IEC 60990:2016)
Verfahren zur Messung von Berührungsstrom und Schutzleiterstrom (IEC 60990:2016) This European Standard was approved by CENELEC on 2016-07-04. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60990:2016 E SIST EN 60990:2017

This document supersedes EN 60990:1999 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 60990:2016 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 60065 NOTE Harmonized as EN 60065. IEC 60309-1:1999 NOTE Harmonized as EN 60309-1:1999 (not modified). IEC 60335-1 NOTE Harmonized as EN 60335-1. IEC 60364-1 NOTE Harmonized as HD 60364-1. IEC 60364-4-41:2005 NOTE Harmonized as HD 60364-4-41:2007 (modified). IEC 60601-1 NOTE Harmonized in EN 60601-1 series. IEC 60950-1 NOTE Harmonized as EN 60950-1. IEC 61010-1 NOTE Harmonized as EN 61010-1. IEC 62368-1 NOTE Harmonized as EN 62368-1.
Normative references to international publications with their corresponding European publications 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. NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu.
Publication Year Title EN/HD Year IEC/TS 60479-1 2005
Effects of current on human beings and livestock - Part 1: General aspects - -
IEC/TS 60479-2 2007
Effects of current on human beings and livestock - Part 2: Special aspects - -
IEC 61140 -
Protection against electric shock - Common aspects for installation and equipment EN 61140 -
ISO/IEC Guide 51 2014
Safety aspects - Guidelines for their inclusion in standards - -
IEC Guide 104 2010 The preparation of safety publications and the use of basic safety publications and group safety publications - -
IEC 60990 Edition 3.0 2016-05 INTERNATIONAL STANDARD NORME INTERNATIONALE Methods of measurement of touch current and protective conductor current
Méthodes de mesure du courant de contact et du courant dans le conducteur de protection
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE
ICS 17.220, 35.020
ISBN 978-2-8322-3420-4
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CONTENTS FOREWORD .6 INTRODUCTION .8 1 Scope . 10 2 Normative references . 10 3 Terms and definitions . 11 4 Test site . 11 4.1 Test site environment . 11 4.2 Test transformer . 12 4.3 Earthed neutral conductor . 12 5 Measuring equipment . 13 5.1 Selection of measuring network . 13 5.1.1 General . 13 5.1.2 Perception and startle-reaction . 14 5.1.3 Letgo-immobilization . 14 5.1.4 Electric burn (a.c.) . 14 5.1.5 Ripple-free d.c. . 14 5.2 Test electrodes . 15 5.2.1 Construction . 15 5.2.2 Connection . 15 5.3 Configuration . 15 5.4 Power connections during test . 15 5.4.1 General . 15 5.4.2 Equipment for use only on TN or TT star power distribution systems . 19 5.4.3 Equipment for use on IT power distribution systems including unearthed delta systems . 19 5.4.4 Equipment for use on single-phase centre-earthed power supply systems or on centre-earthed delta power supply systems . 20 5.5 Supply voltage and frequency . 20 5.5.1 Supply voltage . 20 5.5.2 Supply frequency . 20 6 Test procedure . 20 6.1 General . 20 6.1.1 Touch current measurements . 20 6.1.2 Control switches, equipment and supply conditions . 21 6.1.3 Use of measuring networks . 21 6.2 Normal and fault conditions of equipment . 21 6.2.1 Normal operation of equipment . 21 6.2.2 Equipment and supply fault conditions . 21 7 Evaluation of results . 23 7.1 Perception, startle-reaction and letgo-immobilization . 23 7.2 Electric burn . 23 8 Measurement of protective conductor current . 23 8.1 General . 23 8.2 Multiple equipment . 24 8.3 Measuring method . 24 SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 3 –
Annex A (normative)
Equipment . 25 Annex B (normative)
Use of a conductive plane . 26 Annex C (normative)
Incidentally connected parts . 27 Annex D (informative)
Choice of current limits . 28 D.1 General . 28 D.2 Limit examples . 28 D.2.1 Ventricular fibrillation . 28 D.2.2 Inability to letgo-immobilization . 28 D.2.3 Startle-reaction . 28 D.2.4 Perception threshold . 28 D.2.5 Special applications . 28 D.3 Choice of limits . 29 D.4 Electric burn effects of touch current . 30 Annex E (informative)
Networks for use in measurement of touch current . 31 E.1 General . 31 E.2 Body impedance network – Figure 3 . 31 E.3 Startle-reaction (and body impedance) network – Figure 4 . 31 E.4 Letgo-immobilization (and body impedance) network – Figure 5 . 32 Annex F (informative)
Measuring network limitations and construction . 33 Annex G (informative)
Construction and application of touch current measuring instruments . 35 G.1 Considerations for selection of components . 35 G.1.1 General . 35 G.1.2 Power rating and inductance for RS and RB . 35 G.1.3 Capacitor CS . 35 G.1.4 Resistors R1, R2 and R3 . 36 G.1.5 Capacitors C1, C2 and C3. 36 G.2 Voltmeter . 36 G.3 Accuracy . 36 G.4 Calibration and application of measuring instruments . 37 G.5 Records . 37 G.6 Confirmation systems . 37 Annex H (informative)
Analysis of frequency filtered touch current circuit measurements . 39 Annex I (informative)
AC power distribution systems (see 5.4) . 47 I.1 General . 47 I.2 TN power systems . 48 I.3 TT power systems . 50 I.4 IT power systems . 51 Annex J (informative)
Routine and periodic touch current tests, and tests after
repair or modification of mains operated equipment . 53 Annex K (normative)
Network performance and calibration . 54 K.1 Network or instrument performance and initial calibration . 54 K.2 Calibration in a confirmation system . 56 K.2.1 General . 56 K.2.2 Measurement of input resistance . 56 K.2.3 Measurement of instrument performance . 56 Bibliography . 59 SIST EN 60990:2017

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Figure 1 – Example of earthed neutral, direct supply . 12 Figure 2 – Example of earthed neutral, with transformer for isolation . 13 Figure 3 – Measuring network, unweighted touch current . 13 Figure 4 – Measuring network, touch current weighted for perception or startle-reaction . 14 Figure 5 – Measuring network, touch current weighted for letgo-immobilization . 14 Figure 6 – Single-phase equipment on star TN or TT system . 16 Figure 7 – Single-phase equipment on centre-earthed TN or TT system . 16 Figure 8 – Single-phase equipment connected line-to-line on star TN or TT system . 17 Figure 9 – Single-phase equipment connected line-to-neutral on star IT system . 17 Figure 10 – Single-phase equipment connected line-to-line on star IT system . 17 Figure 11 – Three-phase equipment on star TN or TT system . 18 Figure 12 – Three-phase equipment on star IT system . 18 Figure 13 – Unearthed delta system . 19 Figure 14 – Three-phase equipment on centre-earthed delta system . 19 Figure A.1 – Equipment . 25 Figure B.1 – Equipment platform . 26 Figure F.1 – Frequency factor for electric burn . 33 Figure F.2 – Frequency factor for perception or startle-reaction . 33 Figure F.3 – Frequency factor for letgo-immobilization . 34 Figure H.1 – Triangular waveform touch current, startle-reaction . 40 Figure H.3 – 1 ms rise time pulse response, startle-reaction . 41 Figure H.4 – 1 ms rise time pulse response, letgo-immobilization . 41 Figure H.5 – Touch current vs. rise time plot, 20 ms square wave . 42 Figure H.6 – PFC SMPS touch current waveform . 42 Figure H.7 – 50 Hz square wave, 0,1 ms rise time, startle-reaction . 43 Figure H.8 – 50 Hz square wave, 0,1 ms rise time, letgo-immobilization . 43 Figure H.9 – IEC TS 60479-2 let-go threshold for AC and DC
combinations augmented by additional data, mA each axis . 44 Figure H.10 – Ex1 case: showing r.m.s. window . 45 Figure H.11 – Waveform ex2 case: showing r.m.s. window . 45 Figure I.1 – Examples of TN-S power system . 48 Figure I.2 – Example of TN-C-S power system . 49 Figure I.3 – Example of TN-C power system . 49 Figure I.4 – Example of single-phase, 3-wire TN-C power system . 50 Figure I.5 – Example of 3-line and neutral TT power system . 50 Figure I.6 – Example of 3-line TT power system . 51 Figure I.7 – Example of 3-line (and neutral) IT power system . 51 Figure I.8 – Example of 3-line IT power system . 52
Table H.1 – Triangular waveform response comparison . 40 Table H.2 – Square wave touch current response . 41 SIST EN 60990:2017

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Table H.3 – Square wave monopolar touch current response . 43 Table H.4 – Mixed ACnDC waveform evaluation, ex1 . 45 Table H.5 – Mixed ACnDC waveform evaluation, ex2 . 46 Table K.1 – Calculated input impedance and transfer impedance for unweighted touch current measuring network (Figure 3) . 54 Table K.2 – Calculated input impedance and transfer impedance
for startle-reaction touch current measuring network (Figure 4) . 55 Table K.3 – Calculated input impedance and transfer impedance for
letgo-immobilization current measuring network (Figure 5) . 55 Table K.4 – Output voltage to input voltage ratios for unweighted touch current measuring network (Figure 3) . 57 Table K.5 – Output voltage to input voltage ratios for
startle-reaction measuring network (Figure 4) . 57 Table K.6 – Output voltage to input voltage ratios for letgo-immobilization measuring network (Figure 5) . 58
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INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
METHODS OF MEASUREMENT OF TOUCH CURRENT AND PROTECTIVE CONDUCTOR CURRENT
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. International Standard IEC 60990 has been prepared by TC 108: Safety of electronic equipment within the field of audio/video, information technology and communication technology. This third edition cancels and replaces the second edition published in 1999. It constitutes a technical revision.
The principal changes in this edition as compared with the second edition are as follows: – the effects names have been updated to reflect increased understanding of the range of effects and is in concert with present usage;
– the conditions of use invoking a GRIPPABLE PART have been reduced in the application of the requirements based upon the current understanding of this effect;
– the references to ISO 10012-1, which has been replaced by management standard of the same number, have been replaced with explanatory text, where needed to maintain the sense of the document;
IEC 60990:2016 © IEC 2016 – 7 –
– former informative Annex H (GRIPPABLE PART) has been deleted from this update as it does not properly represent the full set of conditions under which immobilization can occur. A new informative Annex H (Analysis of frequency filtered touch current circuits measurement) has been added;
– the Bibliography (formerly Annex M) has been updated with additional references for completeness.
The text of this standard is based on the following documents: FDIS Report on voting 108/630/FDIS 108/640/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. In this standard, the following print types or formats are used: – requirements proper and normative annexes: in roman type; – compliance statements and test specifications: in italic type; – notes/explanatory matter: in smaller roman type; – normative conditions within tables: in smaller roman type; – terms defined in Clause 3: SMALL CAPITALS. The committee has decided that the contents of this publication will remain unchanged until the maintenance result 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.
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.
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INTRODUCTION This International Standard was developed as a response to concerns arising from the advent of electronic switching techniques being broadly applied to power systems and within EQUIPMENT, giving rise to high-frequency harmonic voltages and currents. This standard is intended for the guidance of EQUIPMENT committees in preparing or amending the test specifications in their standards for measurement of leakage current. However the term "leakage current" is not used for reasons explained below. This standard was initially prepared under the basic safety function assigned to TC 74 (now TC 108), as follows: Methods of measuring leakage current This includes, for various types of EQUIPMENT, all aspects of what is referred to as "leakage current", including methods of measurement of current with regard to physiological effects and for installation purposes, under normal conditions and under certain fault conditions.
The methods of measurement of leakage current described herein result from the review of IEC TS 60479-1 and other publications, including descriptions of earlier methods of measurement. The following conclusions were derived from a review of the effects of leakage current: – the primary concern for safety involves possible flow of harmful current through the human body (this current is not necessarily equal to the current flowing through a protective conductor); – the effect of electric current on a human body is found to be somewhat more complex than was assumed during the development of earlier standards in that there are several body responses which should be considered. The most significant responses for setting limits for continuous waveforms are • perception, • startle-reaction, • letgo-immobilization, and • ELECTRIC BURN. Each of these four body responses has a unique threshold level. There are also significant differences in the manner in which some of these thresholds vary with frequency. Two types of current have been identified as needing separate measuring methods: TOUCH CURRENT and PROTECTIVE CONDUCTOR CURRENT. TOUCH CURRENT only exists when a human body or a body model is a current pathway. It was also noted that the term "leakage current" has already been applied to several different concerns: TOUCH CURRENT, PROTECTIVE CONDUCTOR CURRENT, insulation properties, etc. Therefore, in this standard, the term "leakage current" is not used. Measurement of TOUCH CURRENT In the past, EQUIPMENT standards have used two traditional techniques for measurement of leakage current. Either the actual current in the protective conductor was measured, or a simple resistor-capacitor network (representing a simple body model) was used, the leakage current being defined as the current through the resistor. SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 9 –
This standard provides measuring methods for the four body responses to the electric current noted above, using a more representative body model. This body model was chosen for most common cases of electric shock in the general sense. With respect to the path of current flow and conditions of contact, a body model approximating full hand-to-hand or hand-to-foot contact in normal conditions is used. For small areas of contact (for example, small, finger contact), a different model may be appropriate but is not covered here. Of the four responses, startle-reaction and letgo-immobilization are related to the peak value of TOUCH CURRENT and vary with frequency. Traditionally, concerns for electric shock have dealt with sinusoidal waveforms, for which r.m.s. measurements are most convenient. Peak measurements are more appropriate for non-sinusoidal waveforms where significant values of TOUCH CURRENT are expected, but are equally suitable for sinusoidal waveforms. The networks specified for the measurement of startle-reaction and letgo-immobilization are frequency-responsive and are so weighted that single limit power-frequency values can be specified and referenced. ELECTRIC BURNS, however, are related to the r.m.s. value of TOUCH CURRENT, and are relatively independent of frequency. For EQUIPMENT where ELECTRIC BURNS may be of concern (see 7.2), two separate measurements are made, one in peak value for electric shock and a second in r.m.s. value for ELECTRIC BURNS each using the appropriate test circuit. EQUIPMENT committees should decide which physiological effects are acceptable and which are not, and then decide on limit values of current. Committees for certain types of EQUIPMENT may adopt simplified procedures based upon this standard. A discussion of limit values, based upon earlier work by various IEC EQUIPMENT committees, is provided in Annex D. Measurement of PROTECTIVE CONDUCTOR CURRENT In certain cases, measurement of the PROTECTIVE CONDUCTOR CURRENT of EQUIPMENT under normal operating conditions is required. Such cases include: – selection of a residual current protection device, – determination when a high integrity protective earth circuit is required, – prevent excessive PROTECTIVE CONDUCTOR CURRENT overload in the electrical installation. The PROTECTIVE CONDUCTOR CURRENT is measured by inserting an ammeter of negligible impedance in series with the EQUIPMENT protective earthing conductor. SIST EN 60990:2017

– 10 – IEC 60990:2016 © IEC 2016
METHODS OF MEASUREMENT OF TOUCH CURRENT AND PROTECTIVE CONDUCTOR CURRENT
1 Scope This International Standard defines measurement methods for – d.c. or a.c. current of sinusoidal or non-sinusoidal waveform, which could flow through the human body, and – current flowing through a protective conductor. The measuring methods recommended for TOUCH CURRENT are based upon the possible effects of current flowing through a human body. In this standard, measurements of current through networks representing the impedance of the human body are referred to as measurements of TOUCH CURRENT. These networks are not necessarily valid for the bodies of animals. The specification or implication of specific limit values is not within the scope of this standard. IEC TS 60479 series provides information regarding the effects of current passing through the human body from which limit values may be derived. This standard is applicable to all classes of EQUIPMENT, according to IEC 61140. The methods of measurement in this standard are not intended to be used for – TOUCH CURRENTS having less than 1 s duration, – patient currents as defined in IEC 60601-1, – a.c. at frequencies below 15 Hz, and – currents above those chosen for ELECTRIC BURN limits. 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 independent of product standards. 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 only apply when specifically referred to or included in the relevant publications. 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 TS 60479-1:2005, Effects of current on human beings and livestock – Part 1: General aspects IEC TS 60479-2:2007, Effects of current on human beings and livestock – Part 2: Special aspects SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 11 –
IEC 61140, Protection against electric shock – Common aspects for installation and equipment ISO/IEC Guide 51:2014, Safety aspects – Guidelines for their inclusion in standards IEC Guide 104:2010, The preparation of safety publications and the use of basic safety publications and group safety publications 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1
TOUCH CURRENT electric current through a human body or through an animal body when it touches one or more accessible parts of an installation or of EQUIPMENT
[SOURCE: IEC 60050-195:1998, 195-05-21] 3.2
PROTECTIVE CONDUCTOR CURRENT current which flows in a protective conductor 3.3
EQUIPMENT organized collection of electromechanical component parts and features to accomplish a defined task (as specified in the relevant product standard).
Note 1 to entry: If not specified in the relevant standard, see Annex A. 3.4
GRIPPABLE PART part of the EQUIPMENT which could supply current through the human hand to cause muscular contraction around the part and an inability to let go Note 1 to entry: Parts which are intended to be gripped with the entire hand are assumed to be grippable without further investigation. 3.5
ELECTRIC BURN burning of the skin or of an organ, caused by passing an electric current across or through the surface
[SOURCE: IEC 60050-604:1987, 604-04-18] 4 Test site 4.1 Test site environment Test site environmental requirements shall be as specified in the EQUIPMENT standard. If limit values of less than 70 µA r.m.s. or 100 µA peak are specified, or if the EQUIPMENT contains large shields which may be driven by high-frequency signals, product committees shall refer to Annex B. SIST EN 60990:2017

– 12 – IEC 60990:2016 © IEC 2016
4.2 Test transformer The use of a test transformer for isolation is optional. For maximum safety, a test transformer for isolation (T2 in Figure 2, T in Figure 6 to Figure 14) shall be used and the main protective earthing terminal of the EQUIPMENT under test (EUT) earthed. Any capacitive leakage in the transformer shall then be taken into account. As an alternative to earthing the EUT, the test transformer secondary and the EUT shall be left floating (not earthed), in which case the capacitive leakage in the test transformer need not be taken into account. If transformer T is not used, the EUT shall be mounted on an insulating stand and appropriate safety precautions taken, in view of the possibility of the body of the EUT being at hazardous voltage. 4.3 Earthed neutral conductor EQUIPMENT intended for connection to a TT or TN power distribution system shall be tested with minimum voltage between neutral and earth. NOTE Descriptions of various power distribution systems are given in Annex I. The protective conductor and the earthed neutral conductor for the EUT should have a voltage difference of less than 1 % of line-to-line voltage (see example in Figure 1). A local transformer, see 4.2, will achieve this requirement. Alternatively, if the voltage difference is 1 % or more, the following are examples of methods which, in some cases, will avoid measurement errors due to this voltage: – connecting the terminal B electrode of the measuring instrument network to the neutral terminal of the EUT instead of the protective earthing conductor (see 6.1.2) of the supply; – connecting the earthing terminal of the EUT to the neutral conductor, instead of the protective earthing conductor, of the supply.
Figure 1 – Example of earthed neutral, direct supply IEC SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 13 –
Figure 2 – Example of earthed neutral, with transformer for isolation 5 Measuring equipment 5.1 Selection of measuring network 5.1.1 General Measurements shall be made with one of the networks of Figure 3, Figure 4 and Figure 5. NOTE See Annexes E, F and G for further explanation of the three networks.
RS 1 500 Ω RB 500 Ω CS 0,22 µF Figure 3 – Measuring network, unweighted touch current IEC IEC SIST EN 60990:2017

– 14 – IEC 60990:2016 © IEC 2016
RS 1 500 Ω R1 10 000 Ω RB 500 Ω C1 0,022 µF CS 0,22 µF
Figure 4 – Measuring network, touch current weighted for perception or startle-reaction
RS 1 500 Ω R3 20 000 Ω RB 500 Ω C2 0,006 2 µF CS 0,22 µF C3 0,009 1 µF R2 10 000 Ω
NOTE For special conditions on the use of this network, see 5.1.2. Figure 5 – Measuring network, touch current weighted for letgo-immobilization 5.1.2 Perception and startle-reaction
The network of Figure 4 shall be used for low level electric shock limits. This circuit is to be applied where the a.c. limit value in the product standard is up to 2 mA r.m.s. or 2,8 mA peak. 5.1.3 Letgo-immobilization
The network of Figure 5 shall be used for higher level electric shock limits. This circuit is to be applied where the a.c. limit value in the product standard is more than 2 mA r.m.s. or 2,8 mA peak. 5.1.4 Electric burn (a.c.) The unweighted TOUCH CURRENT network of Figure 3 shall be used. 5.1.5 Ripple-free d.c. Any one of the three networks shall be used. Unless otherwise specified in the EQUIPMENT standard, ripple-free d.c. means less than 10 % peak-to-peak ripple. IEC IEC SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 15 –
5.2 Test electrodes 5.2.1 Construction Unless otherwise specified in the EQUIPMENT standard, the test electrodes shall be – a test clip, or – a 10 cm × 20 cm metal foil to represent the human hand. Where adhesive metal foil is used, the adhesive shall be conductive. 5.2.2 Connection Test electrodes shall be connected to test terminals A and B of the measuring network. 5.3 Configuration The EQUIPMENT under test (EUT) shall be fully assembled and ready for use in the maximum configuration; it shall be connected to external signal voltages where applicable, as specified by the manufacturer for a single EQUIPMENT. EQUIPMENT which is designed for multiple power sources, only one of which is required at a time (for example, for backup), shall be tested with only one source connected. EQUIPMENT requiring power simultaneously from two or more power sources shall be tested with all power sources connected but with not more than one connection to protective earth. 5.4 Power connections during test 5.4.1 General NOTE Examples of power distribution systems are given in Annex I. EQUIPMENT shall be connected in a test configuration as shown in Figure 6 to Figure 14, according to 5.4.2, 5.4.3 or 5.4.4, as appropriate. EQUIPMENT committees should consider the possible need for the manufacturer to identify the power distribution system (TN, TT, IT) to which an EQUIPMENT is intended to be connected in its final application. If the EUT is specified by the manufacturer for use only on certain power distribution systems, the EUT shall be tested only when connected to those systems. EQUIPMENT to be connected only to TN or TT systems shall comply with 5.4.2. EQUIPMENT to be connected to IT systems shall comply with 5.4.3 and may also be connected to TN or TT systems. For Class 0 and Class II EQUIPMENT (see IEC 61140), the protective conductors in Figure 6 through Figure 14 are ignored. SIST EN 60990:2017

– 16 – IEC 60990:2016 © IEC 2016
Figure 6 – Single-phase equipment on star TN or TT system
The centre-tapped winding may be one leg of a delta supply. Figure 7 – Single-phase equipment on centre-earthed TN or TT system IEC IEC SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 17 –
Figure 8 – Single-phase equipment connected line-to-line on star TN or TT system
The 1 000 Ω resistor should be rated for supply system faults.
Figure 9 – Single-phase equipment connected line-to-neutral on star IT system
The 1 000 Ω resistor should be rated for supply system faults.
Figure 10 – Single-phase equipment connected line-to-line on star IT system IEC IEC IEC SIST EN 60990:2017

– 18 – IEC 60990:2016 © IEC 2016
Figure 11 – Three-phase equipment on star TN or TT system
The 1 000 Ω resistor should be rated for supply system faults. Figure 12 – Three-phase equipment on star IT system IEC IEC SIST EN 60990:2017

IEC 60990:2016 © IEC 2016 – 19 –
Figure 13 – Unearthed delta system
Where an EQUIPMENT contains both a three-phase load and a centre-earthed single-phase load, and the earthed side is identified, switch g shall remain in the position
...

SLOVENSKI STANDARD
01-februar-2017
Nadomešča:
SIST EN 60990:2002
Metode merjenja toka dotika in toka v zaščitnem vodniku
Methods of measurement of touch current and protective conductor current
Verfahren zur Messung von Berührungsstrom und Schutzleiterstrom
Méthodes de mesure du courant de contact et du courant dans le conducteur de
protection
Ta slovenski standard je istoveten z: EN 60990:2016
ICS:
13.260 Varstvo pred električnim Protection against electric
udarom. Delo pod napetostjo shock. Live working
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 60990
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2016
ICS 17.220; 35.020 Supersedes EN 60990:1999
English Version
Methods of measurement of touch current and
protective conductor current
(IEC 60990:2016)
Méthodes de mesure du courant de contact et  Verfahren zur Messung von Berührungsstrom und
du courant dans le conducteur de protection Schutzleiterstrom
(IEC 60990:2016) (IEC 60990:2016)
This European Standard was approved by CENELEC on 2016-07-04. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60990:2016 E
European foreword
The text of document 108/630/FDIS, future edition 3 of IEC 60990, prepared by IEC/TC 108 "Safety of
electronic equipment within the field of audio/video, information technology and communication
technology" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at (dop) 2017-04-04
national level by publication of an identical national
standard or by endorsement
(dow) 2019-07-04
• latest date by which the national standards conflicting with
the document have to be withdrawn

This document supersedes EN 60990:1999
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 60990:2016 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60065 NOTE Harmonized as EN 60065.
IEC 60309-1:1999 NOTE Harmonized as EN 60309-1:1999 (not modified).
IEC 60335-1 NOTE Harmonized as EN 60335-1.
IEC 60364-1 NOTE Harmonized as HD 60364-1.
IEC 60364-4-41:2005 NOTE Harmonized as HD 60364-4-41:2007 (modified).
IEC 60601-1 NOTE Harmonized in EN 60601-1 series.
IEC 60950-1 NOTE Harmonized as EN 60950-1.
IEC 61010-1 NOTE Harmonized as EN 61010-1.
IEC 62368-1 NOTE Harmonized as EN 62368-1.

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is
available here: www.cenelec.eu.

Publication Year Title EN/HD Year
IEC/TS 60479-1 2005 Effects of current on human beings and - -
livestock -
Part 1: General aspects
IEC/TS 60479-2 2007 Effects of current on human beings and - -
livestock -
Part 2: Special aspects
IEC 61140 -  Protection against electric shock - EN 61140 -
Common aspects for installation and
equipment
ISO/IEC Guide 51 2014 Safety aspects - Guidelines for their - -
inclusion in standards
IEC Guide 104 2010 The preparation of safety publications - -
and the use of basic safety publications
and group safety publications
IEC 60990 ®
Edition 3.0 2016-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Methods of measurement of touch current and protective conductor current

Méthodes de mesure du courant de contact et du courant dans le conducteur de

protection
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220, 35.020 ISBN 978-2-8322-3420-4

– 2 – IEC 60990:2016 © IEC 2016
CONTENTS
FOREWORD .6
INTRODUCTION .8
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 11
4 Test site . 11
4.1 Test site environment . 11
4.2 Test transformer . 12
4.3 Earthed neutral conductor . 12
5 Measuring equipment . 13
5.1 Selection of measuring network . 13
5.1.1 General . 13
5.1.2 Perception and startle-reaction . 14
5.1.3 Letgo-immobilization . 14
5.1.4 Electric burn (a.c.) . 14
5.1.5 Ripple-free d.c. . 14
5.2 Test electrodes . 15
5.2.1 Construction . 15
5.2.2 Connection . 15
5.3 Configuration . 15
5.4 Power connections during test . 15
5.4.1 General . 15
5.4.2 Equipment for use only on TN or TT star power distribution systems . 19
5.4.3 Equipment for use on IT power distribution systems including
unearthed delta systems . 19
5.4.4 Equipment for use on single-phase centre-earthed power supply
systems or on centre-earthed delta power supply systems . 20
5.5 Supply voltage and frequency . 20
5.5.1 Supply voltage . 20
5.5.2 Supply frequency . 20
6 Test procedure . 20
6.1 General . 20
6.1.1 Touch current measurements . 20
6.1.2 Control switches, equipment and supply conditions . 21
6.1.3 Use of measuring networks . 21
6.2 Normal and fault conditions of equipment . 21
6.2.1 Normal operation of equipment . 21
6.2.2 Equipment and supply fault conditions . 21
7 Evaluation of results . 23
7.1 Perception, startle-reaction and letgo-immobilization . 23
7.2 Electric burn . 23
8 Measurement of protective conductor current . 23
8.1 General . 23
8.2 Multiple equipment . 24
8.3 Measuring method . 24

IEC 60990:2016 © IEC 2016 – 3 –
Annex A (normative) Equipment . 25
Annex B (normative) Use of a conductive plane . 26
Annex C (normative) Incidentally connected parts . 27
Annex D (informative) Choice of current limits . 28
D.1 General . 28
D.2 Limit examples . 28
D.2.1 Ventricular fibrillation . 28
D.2.2 Inability to letgo-immobilization . 28
D.2.3 Startle-reaction . 28
D.2.4 Perception threshold . 28
D.2.5 Special applications . 28
D.3 Choice of limits . 29
D.4 Electric burn effects of touch current . 30
Annex E (informative) Networks for use in measurement of touch current . 31
E.1 General . 31
E.2 Body impedance network – Figure 3 . 31
E.3 Startle-reaction (and body impedance) network – Figure 4 . 31
E.4 Letgo-immobilization (and body impedance) network – Figure 5 . 32
Annex F (informative) Measuring network limitations and construction . 33
Annex G (informative) Construction and application of touch current measuring
instruments . 35
G.1 Considerations for selection of components . 35
G.1.1 General . 35
G.1.2 Power rating and inductance for R and R . 35
S B
G.1.3 Capacitor C . 35
S
G.1.4 Resistors R1, R2 and R3 . 36
G.1.5 Capacitors C1, C2 and C3. 36
G.2 Voltmeter . 36
G.3 Accuracy . 36
G.4 Calibration and application of measuring instruments . 37
G.5 Records . 37
G.6 Confirmation systems . 37
Annex H (informative) Analysis of frequency filtered touch current circuit
measurements . 39
Annex I (informative) AC power distribution systems (see 5.4) . 47
I.1 General . 47
I.2 TN power systems . 48
I.3 TT power systems . 50
I.4 IT power systems . 51
Annex J (informative) Routine and periodic touch current tests, and tests after repair
or modification of mains operated equipment . 53
Annex K (normative) Network performance and calibration . 54
K.1 Network or instrument performance and initial calibration . 54
K.2 Calibration in a confirmation system . 56
K.2.1 General . 56
K.2.2 Measurement of input resistance . 56
K.2.3 Measurement of instrument performance . 56
Bibliography . 59

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Figure 1 – Example of earthed neutral, direct supply . 12
Figure 2 – Example of earthed neutral, with transformer for isolation . 13
Figure 3 – Measuring network, unweighted touch current . 13
Figure 4 – Measuring network, touch current weighted for perception or startle-
reaction . 14
Figure 5 – Measuring network, touch current weighted for letgo-immobilization . 14
Figure 6 – Single-phase equipment on star TN or TT system . 16
Figure 7 – Single-phase equipment on centre-earthed TN or TT system . 16
Figure 8 – Single-phase equipment connected line-to-line on star TN or TT system . 17
Figure 9 – Single-phase equipment connected line-to-neutral on star IT system . 17
Figure 10 – Single-phase equipment connected line-to-line on star IT system . 17
Figure 11 – Three-phase equipment on star TN or TT system . 18
Figure 12 – Three-phase equipment on star IT system . 18
Figure 13 – Unearthed delta system . 19
Figure 14 – Three-phase equipment on centre-earthed delta system . 19
Figure A.1 – Equipment . 25
Figure B.1 – Equipment platform . 26
Figure F.1 – Frequency factor for electric burn . 33
Figure F.2 – Frequency factor for perception or startle-reaction . 33
Figure F.3 – Frequency factor for letgo-immobilization . 34
Figure H.1 – Triangular waveform touch current, startle-reaction . 40
Figure H.3 – 1 ms rise time pulse response, startle-reaction . 41
Figure H.4 – 1 ms rise time pulse response, letgo-immobilization . 41
Figure H.5 – Touch current vs. rise time plot, 20 ms square wave . 42
Figure H.6 – PFC SMPS touch current waveform . 42
Figure H.7 – 50 Hz square wave, 0,1 ms rise time, startle-reaction . 43
Figure H.8 – 50 Hz square wave, 0,1 ms rise time, letgo-immobilization . 43
Figure H.9 – IEC TS 60479-2 let-go threshold for AC and DC combinations
augmented by additional data, mA each axis . 44
Figure H.10 – Ex1 case: showing r.m.s. window . 45
Figure H.11 – Waveform ex2 case: showing r.m.s. window . 45
Figure I.1 – Examples of TN-S power system . 48
Figure I.2 – Example of TN-C-S power system . 49
Figure I.3 – Example of TN-C power system . 49
Figure I.4 – Example of single-phase, 3-wire TN-C power system . 50
Figure I.5 – Example of 3-line and neutral TT power system . 50
Figure I.6 – Example of 3-line TT power system . 51
Figure I.7 – Example of 3-line (and neutral) IT power system . 51
Figure I.8 – Example of 3-line IT power system . 52

Table H.1 – Triangular waveform response comparison . 40
Table H.2 – Square wave touch current response . 41

IEC 60990:2016 © IEC 2016 – 5 –
Table H.3 – Square wave monopolar touch current response . 43
Table H.4 – Mixed ACnDC waveform evaluation, ex1 . 45
Table H.5 – Mixed ACnDC waveform evaluation, ex2 . 46
Table K.1 – Calculated input impedance and transfer impedance for unweighted touch
current measuring network (Figure 3) . 54
Table K.2 – Calculated input impedance and transfer impedance for startle-reaction
touch current measuring network (Figure 4) . 55
Table K.3 – Calculated input impedance and transfer impedance for letgo-
immobilization current measuring network (Figure 5) . 55
Table K.4 – Output voltage to input voltage ratios for unweighted touch current
measuring network (Figure 3) . 57
Table K.5 – Output voltage to input voltage ratios for startle-reaction measuring
network (Figure 4) . 57
Table K.6 – Output voltage to input voltage ratios for letgo-immobilization measuring
network (Figure 5) . 58

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METHODS OF MEASUREMENT OF TOUCH CURRENT
AND PROTECTIVE CONDUCTOR CURRENT

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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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 60990 has been prepared by TC 108: Safety of electronic
equipment within the field of audio/video, information technology and communication
technology.
This third edition cancels and replaces the second edition published in 1999. It constitutes a
technical revision.
The principal changes in this edition as compared with the second edition are as follows:
– the effects names have been updated to reflect increased understanding of the range of
effects and is in concert with present usage;
– the conditions of use invoking a GRIPPABLE PART have been reduced in the application of
the requirements based upon the current understanding of this effect;
– the references to ISO 10012-1, which has been replaced by management standard of the
same number, have been replaced with explanatory text, where needed to maintain the
sense of the document;
IEC 60990:2016 © IEC 2016 – 7 –
– former informative Annex H (GRIPPABLE PART) has been deleted from this update as it
does not properly represent the full set of conditions under which immobilization can
occur. A new informative Annex H (Analysis of frequency filtered touch current circuits
measurement) has been added;
– the Bibliography (formerly Annex M) has been updated with additional references for
completeness.
The text of this standard is based on the following documents:
FDIS Report on voting
108/630/FDIS 108/640/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.
In this standard, the following print types or formats are used:
– requirements proper and normative annexes: in roman type;
– compliance statements and test specifications: in italic type;
– notes/explanatory matter: in smaller roman type;
– normative conditions within tables: in smaller roman type;
– terms defined in Clause 3: SMALL CAPITALS.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
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.
– 8 – IEC 60990:2016 © IEC 2016
INTRODUCTION
This International Standard was developed as a response to concerns arising from the advent
of electronic switching techniques being broadly applied to power systems and within
EQUIPMENT, giving rise to high-frequency harmonic voltages and currents.
This standard is intended for the guidance of EQUIPMENT committees in preparing or
amending the test specifications in their standards for measurement of leakage current.
However the term "leakage current" is not used for reasons explained below.
This standard was initially prepared under the basic safety function assigned to TC 74 (now
TC 108), as follows:
Methods of measuring leakage current
This includes, for various types of EQUIPMENT, all aspects of what is referred to as "leakage
current", including methods of measurement of current with regard to physiological effects
and for installation purposes, under normal conditions and under certain fault conditions.
The methods of measurement of leakage current described herein result from the review of
IEC TS 60479-1 and other publications, including descriptions of earlier methods of
measurement.
The following conclusions were derived from a review of the effects of leakage current:
– the primary concern for safety involves possible flow of harmful current through the
human body (this current is not necessarily equal to the current flowing through a
protective conductor);
– the effect of electric current on a human body is found to be somewhat more complex
than was assumed during the development of earlier standards in that there are several
body responses which should be considered. The most significant responses for setting
limits for continuous waveforms are
• perception,
• startle-reaction,
• letgo-immobilization, and
• ELECTRIC BURN.
Each of these four body responses has a unique threshold level. There are also significant
differences in the manner in which some of these thresholds vary with frequency.
Two types of current have been identified as needing separate measuring methods: TOUCH
CURRENT and PROTECTIVE CONDUCTOR CURRENT.
TOUCH CURRENT only exists when a human body or a body model is a current pathway.
It was also noted that the term "leakage current" has already been applied to several different
concerns: TOUCH CURRENT, PROTECTIVE CONDUCTOR CURRENT, insulation properties, etc.
Therefore, in this standard, the term "leakage current" is not used.
Measurement of TOUCH CURRENT
In the past, EQUIPMENT standards have used two traditional techniques for measurement of
leakage current. Either the actual current in the protective conductor was measured, or a
simple resistor-capacitor network (representing a simple body model) was used, the leakage
current being defined as the current through the resistor.

IEC 60990:2016 © IEC 2016 – 9 –
This standard provides measuring methods for the four body responses to the electric current
noted above, using a more representative body model.
This body model was chosen for most common cases of electric shock in the general sense.
With respect to the path of current flow and conditions of contact, a body model
approximating full hand-to-hand or hand-to-foot contact in normal conditions is used. For
small areas of contact (for example, small, finger contact), a different model may be
appropriate but is not covered here.
Of the four responses, startle-reaction and letgo-immobilization are related to the peak value
of TOUCH CURRENT and vary with frequency. Traditionally, concerns for electric shock have
dealt with sinusoidal waveforms, for which r.m.s. measurements are most convenient. Peak
measurements are more appropriate for non-sinusoidal waveforms where significant values
of TOUCH CURRENT are expected, but are equally suitable for sinusoidal waveforms. The
networks specified for the measurement of startle-reaction and letgo-immobilization are
frequency-responsive and are so weighted that single limit power-frequency values can be
specified and referenced.
ELECTRIC BURNS, however, are related to the r.m.s. value of TOUCH CURRENT, and are relatively
independent of frequency. For EQUIPMENT where ELECTRIC BURNS may be of concern (see
7.2), two separate measurements are made, one in peak value for electric shock and a
second in r.m.s. value for ELECTRIC BURNS each using the appropriate test circuit.
EQUIPMENT committees should decide which physiological effects are acceptable and which
are not, and then decide on limit values of current. Committees for certain types of EQUIPMENT
may adopt simplified procedures based upon this standard. A discussion of limit values,
based upon earlier work by various IEC EQUIPMENT committees, is provided in Annex D.
Measurement of PROTECTIVE CONDUCTOR CURRENT
In certain cases, measurement of the PROTECTIVE CONDUCTOR CURRENT of EQUIPMENT under
normal operating conditions is required. Such cases include:
– selection of a residual current protection device,
– determination when a high integrity protective earth circuit is required,
– prevent excessive PROTECTIVE CONDUCTOR CURRENT overload in the electrical installation.
The PROTECTIVE CONDUCTOR CURRENT is measured by inserting an ammeter of negligible
impedance in series with the EQUIPMENT protective earthing conductor.

– 10 – IEC 60990:2016 © IEC 2016
METHODS OF MEASUREMENT OF TOUCH CURRENT
AND PROTECTIVE CONDUCTOR CURRENT

1 Scope
This International Standard defines measurement methods for
– d.c. or a.c. current of sinusoidal or non-sinusoidal waveform, which could flow through the
human body, and
– current flowing through a protective conductor.
The measuring methods recommended for TOUCH CURRENT are based upon the possible
effects of current flowing through a human body. In this standard, measurements of current
through networks representing the impedance of the human body are referred to as
measurements of TOUCH CURRENT. These networks are not necessarily valid for the bodies of
animals.
The specification or implication of specific limit values is not within the scope of this standard.
IEC TS 60479 series provides information regarding the effects of current passing through
the human body from which limit values may be derived.
This standard is applicable to all classes of EQUIPMENT, according to IEC 61140.
The methods of measurement in this standard are not intended to be used for
– TOUCH CURRENTS having less than 1 s duration,
– patient currents as defined in IEC 60601-1,
– a.c. at frequencies below 15 Hz, and
– currents above those chosen for ELECTRIC BURN limits.
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
independent of product standards.
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 only apply when specifically
referred to or included in the relevant publications.
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 TS 60479-1:2005, Effects of current on human beings and livestock – Part 1: General
aspects
IEC TS 60479-2:2007, Effects of current on human beings and livestock – Part 2: Special
aspects
IEC 60990:2016 © IEC 2016 – 11 –
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
ISO/IEC Guide 51:2014, Safety aspects – Guidelines for their inclusion in standards
IEC Guide 104:2010, The preparation of safety publications and the use of basic safety
publications and group safety publications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
TOUCH CURRENT
electric current through a human body or through an animal body when it touches one or
more accessible parts of an installation or of EQUIPMENT
[SOURCE: IEC 60050-195:1998, 195-05-21]
3.2
PROTECTIVE CONDUCTOR CURRENT
current which flows in a protective conductor
3.3
EQUIPMENT
organized collection of electromechanical component parts and features to accomplish a
defined task (as specified in the relevant product standard).
Note 1 to entry: If not specified in the relevant standard, see Annex A.
3.4
GRIPPABLE PART
part of the EQUIPMENT which could supply current through the human hand to cause muscular
contraction around the part and an inability to let go
Note 1 to entry: Parts which are intended to be gripped with the entire hand are assumed to be grippable without
further investigation.
3.5
ELECTRIC BURN
burning of the skin or of an organ, caused by passing an electric current across or through
the surface
[SOURCE: IEC 60050-604:1987, 604-04-18]
4 Test site
4.1 Test site environment
Test site environmental requirements shall be as specified in the EQUIPMENT standard. If limit
values of less than 70 µA r.m.s. or 100 µA peak are specified, or if the EQUIPMENT contains
large shields which may be driven by high-frequency signals, product committees shall refer
to Annex B.
– 12 – IEC 60990:2016 © IEC 2016
4.2 Test transformer
The use of a test transformer for isolation is optional. For maximum safety, a test transformer
for isolation (T2 in Figure 2, T in Figure 6 to Figure 14) shall be used and the main protective
earthing terminal of the EQUIPMENT under test (EUT) earthed. Any capacitive leakage in the
transformer shall then be taken into account. As an alternative to earthing the EUT, the test
transformer secondary and the EUT shall be left floating (not earthed), in which case the
capacitive leakage in the test transformer need not be taken into account.
If transformer T is not used, the EUT shall be mounted on an insulating stand and appropriate
safety precautions taken, in view of the possibility of the body of the EUT being at hazardous
voltage.
4.3 Earthed neutral conductor
EQUIPMENT intended for connection to a TT or TN power distribution system shall be tested
with minimum voltage between neutral and earth.
NOTE Descriptions of various power distribution systems are given in Annex I.
The protective conductor and the earthed neutral conductor for the EUT should have a
voltage difference of less than 1 % of line-to-line voltage (see example in Figure 1).
A local transformer, see 4.2, will achieve this requirement.
Alternatively, if the voltage difference is 1 % or more, the following are examples of methods
which, in some cases, will avoid measurement errors due to this voltage:
– connecting the terminal B electrode of the measuring instrument network to the neutral
terminal of the EUT instead of the protective earthing conductor (see 6.1.2) of the supply;
– connecting the earthing terminal of the EUT to the neutral conductor, instead of the
protective earthing conductor, of the supply.
IEC
Figure 1 – Example of earthed neutral, direct supply

IEC 60990:2016 © IEC 2016 – 13 –

IEC
Figure 2 – Example of earthed neutral, with transformer for isolation
5 Measuring equipment
5.1 Selection of measuring network
5.1.1 General
Measurements shall be made with one of the networks of Figure 3, Figure 4 and Figure 5.
NOTE See Annexes E, F and G for further explanation of the three networks.
IEC
R 1 500 Ω
S
R 500 Ω
B
C 0,22 µF
S
Figure 3 – Measuring network, unweighted touch current

– 14 – IEC 60990:2016 © IEC 2016

IEC
R 1 500 Ω R 10 000 Ω
S 1
R 500 Ω C 0,022 µF
B 1
C 0,22 µF
S
Figure 4 – Measuring network, touch current weighted for perception or startle-reaction
IEC
R 1 500 Ω R 20 000 Ω
S 3
R 500 Ω C 0,006 2 µF
B 2
C 0,22 µF C 0,009 1 µF
S 3
R 10 000 Ω
NOTE For special conditions on the use of this network, see 5.1.2.
Figure 5 – Measuring network, touch current weighted for letgo-immobilization
5.1.2 Perception and startle-reaction
The network of Figure 4 shall be used for low level electric shock limits. This circuit is to be
applied where the a.c. limit value in the product standard is up to 2 mA r.m.s. or 2,8 mA peak.
5.1.3 Letgo-immobilization
The network of Figure 5 shall be used for higher level electric shock limits. This circuit is to
be applied where the a.c. limit value in the product standard is more than 2 mA r.m.s. or
2,8 mA peak.
5.1.4 Electric burn (a.c.)
The unweighted TOUCH CURRENT network of Figure 3 shall be used.
5.1.5 Ripple-free d.c.
Any one of the three networks shall be used. Unless otherwise specified in the EQUIPMENT
standard, ripple-free d.c. means less than 10 % peak-to-peak ripple.

IEC 60990:2016 © IEC 2016 – 15 –
5.2 Test electrodes
5.2.1 Construction
Unless otherwise specified in the EQUIPMENT standard, the test electrodes shall be
– a test clip, or
– a 10 cm × 20 cm metal foil to represent the human hand. Where adhesive metal foil is
used, the adhesive shall be conductive.
5.2.2 Connection
Test electrodes shall be connected to test terminals A and B of the measuring network.
5.3 Configuration
The EQUIPMENT under test (EUT) shall be fully assembled and ready for use in the maximum
configuration; it shall be connected to external signal voltages where applicable, as specified
by the manufacturer for a single EQUIPMENT.
EQUIPMENT which is designed for multiple power sources, only one of which is required at a
time (for example, for backup), s
...