IEC 61204-7:2016

Low-voltage switch mode power supplies - Part 7: Safety requirements

IEC 61204-7:2016 specifies the safety requirements for switch mode power supply (SMPS) units supplied by source voltages up to 1 000 V AC or 1 500 V DC providing AC and/or DC output(s), except inverter output(s) establishing AC mains. This product standard covers both stand-alone and component SMPS as defined in this document. DC power and distribution equipment which provides, distributes, monitors, and controls isolated secondary circuit power to other equipment typically used in information and communication technology equipment installations. This edition includes the following significant technical changes with respect to the previous edition:
a) use of IEC 62477-1 as reference document, instead of IEC 60950-1;
b) modification of the title by deleting the wording "DC output-" and adding "switch mode".

Alimentations à découpage basse tension - Partie 7: Exigences de sécurité

L'IEC 61204-7:2016 spécifie les exigences de sécurité pour les alimentations à découpage (SMPS) alimentées par des sources ne dépassant pas 1 000 V en courant alternatif et 1 500 V en courant continu, fournissant un courant alternatif et/ou continu, à l'exception de la ou des sorties de l'onduleur alimentant le réseau en courant alternatif. Le présent document de produit couvre à la fois les SMPS autonomes et composants telles que définies dans le présent document. Les appareils d'alimentation et de distribution en courant continu fournissent, distribuent, surveillent et contrôlent l'alimentation isolée du circuit secondaire à d'autres appareils généralement utilisés dans les installations des équipements des technologies de l'information et de la communication. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) utilisation de l'IEC 62477-1 comme document de référence, en lieu et place de l'IEC 60950-1;
b) modification du titre avec la suppression des termes "sortie continue" et l'ajout des termes "à découpage".

General Information

• Status: Published
• Publication Date: 06-Nov-2016
• ICS: 29.200 - Rectifiers. Convertors. Stabilized power supply
• Technical Committee: SC 22E - Stabilized power supplies
• Drafting Committee: MT 7 - TC 22/SC 22E/MT 7
• Current Stage: PPUB - Publication issued
• Start Date: 07-Nov-2016
• Completion Date: 30-Nov-2016

Relations

• Revises: IEC 61204-7:2006 - Low-voltage power supplies, d.c. output - Part 7: Safety requirements
• Effective Date: 05-Sep-2023

Overview

IEC 61204-7:2016 - Low‑voltage switch mode power supplies - Part 7: Safety requirements - is the IEC product standard that sets safety requirements for low‑voltage switch mode power supplies (SMPS). It applies to SMPS units supplied from source voltages up to 1 000 V AC or 1 500 V DC and covering AC and/or DC outputs, except inverter outputs that establish AC mains. The standard covers both stand‑alone and component SMPS and integrates the general safety rules of IEC 62477‑1:2012 (replacing IEC 60950‑1 as a reference), reflecting updated safety principles for modern power conversion equipment.

Key topics and technical requirements

The standard organizes comprehensive safety provisions and test requirements, including:

• Protection against electric shock: insulation requirements, decisive voltage classes, basic and fault protection, enhanced protective measures and compatibility with residual‑current devices.
• Energy and fire hazards: limits on circuits/components that present fire or thermal risk, fire enclosures and temperature constraints.
• Fault and abnormal condition handling: design and test requirements for short‑circuit, overload, and fault conditions including coordination of protection devices.
• Mechanical and environmental protection: enclosure design, stability, routing of wiring, mechanical hazards and environmental stress testing (temperature, humidity, pressure).
• Components and assemblies: requirements and tests for switches, over‑temperature devices, transformers, motors, mains supply cords and other protective devices.
• Test and verification: type, sample and routine tests (visual, mechanical, electrical, abnormal operation, material and environmental tests) plus test sequencing and compliance criteria.
• Information, marking and documentation: requirements for selection, installation, commissioning, maintenance information and mandatory marking for safe use.

Practical applications - who uses IEC 61204‑7:2016

This standard is essential for:

• SMPS designers and manufacturers specifying safety features and component selection.
• Compliance and safety engineers conducting risk assessment and product certification.
• Test laboratories and notified bodies performing type and routine safety testing.
• Purchasing/specification teams in industrial, ICT and instrumentation sectors procuring safe power supplies.
• System integrators and OEMs using component SMPS within larger equipment to ensure end‑product compliance.

Related standards

• IEC 62477‑1:2012 - General rules for safety of power electronic converters (referenced by IEC 61204‑7).
• Historical reference: IEC 60950‑1 (replaced in this edition as the primary reference).

IEC 61204‑7:2016 is a key standard for ensuring the safe design, testing and documentation of low‑voltage SMPS, helping manufacturers and users reduce electrical, thermal and mechanical hazards while meeting global safety expectations.

Standards Content (Sample)

IEC 61204-7 ®
Edition 2.0 2016-11
EXTENDED VERSION
colour
inside
This Extended version of IEC 61204-7:2016 includes the provisions of the general rules of
IEC 62477-1:2012
Low-voltage switch mode power supplies –
Part 7: Safety requirements
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 15 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC 61204-7 ®
Edition 2.0 2016-11
EXTENDED VERSION
colour
inside
This Extended version of IEC 61204-7:2016 includes the provisions of the general rules of

IEC 62477-1:2012
Low-voltage switch mode power supplies –

Part 7: Safety requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.200 ISBN 978-2-8322-3751-9

– 2 – IEC 61204-7:2016 EXV  IEC 2016
CONTENTS
FOREWORD . 9
INTRODUCTION . 12
0 Principles of safety . 13
0.1 General . 13
0.2 Hazards . 14
0.2.1 General . 14
0.2.2 Electric shock . 14
0.2.3 Energy related hazards . 15
0.2.4 Fire . 15
0.2.5 Heat related hazards . 16
0.2.6 Mechanical hazards . 16
0.2.7 Chemical hazards . 16
0.3 Materials and components . 16
1 Scope . 17
1.1 Equipment covered by this document . 17
1.2 Exclusions . 17
1.3 Additional requirements . 18
2 Normative references . 18
3 Terms and definitions . 19
4 Protection against hazards . 29
4.1 General . 29
4.1.100 Constructions not specifically covered . 30
4.1.101 Orientation during transport and use . 30
4.2 Fault and abnormal conditions . 30
4.2.100 Application of faults and abnormal conditions . 31
4.3 Short circuit and overload protection . 32
4.3.1 General . 32
4.3.2 Specification of input short-circuit withstand strength and output short
circuit current ability . 33
4.3.3 Short-circuit coordination (backup protection) . 34
4.3.4 Protection by several devices . 34
4.4 Protection against electric shock . 34
4.4.1 General . 34
4.4.2 Decisive voltage class . 34
4.4.3 Provision for basic protection . 37
4.4.4 Provision for fault protection . 38
4.4.5 Enhanced protection . 44
4.4.6 Protective measures . 47
4.4.7 Insulation . 49
4.4.8 Compatibility with residual current-operated protective devices (RCD) . 67
4.4.9 Capacitor discharge . 67
4.5 Protection against electrical energy hazards . 68
4.5.1 Operator access areas. 68
4.5.2 Service access areas . 69
4.6 Protection against fire and thermal hazards . 69
4.6.1 Circuits representing a fire hazard . 69

4.6.2 Components representing a fire hazard . 69
4.6.3 Fire enclosures . 70
4.6.4 Temperature limits . 74
4.6.5 Limited power sources . 78
4.7 Protection against mechanical hazards . 79
4.7.1 General . 79
4.7.2 Specific requirements for liquid cooled SMPS . 79
4.8 Equipment with multiple sources of supply . 81
4.9 Protection against environmental stresses . 81
4.10 Protection against sonic pressure hazards . 82
4.10.1 General . 82
4.10.2 Sonic pressure and sound level . 82
4.11 Wiring and connections . 83
4.11.1 General . 83
4.11.2 Routing . 83
4.11.3 Colour coding . 83
4.11.4 Splices and connections . 83
4.11.5 Accessible connections . 84
4.11.6 Interconnections between parts of the SMPS . 84
4.11.7 Supply connections. 84
4.11.8 Terminals . 84
4.12 Enclosures . 86
4.12.1 General . 86
4.12.2 Handles and manual controls . 86
4.12.3 Cast metal . 87
4.12.4 Sheet metal . 87
4.12.5 Stability test for enclosure . 90
5 Test requirements . 91
5.1 General . 91
5.1.1 Test objectives and classification . 91
5.1.2 Selection of test samples . 91
5.1.3 Sequence of tests . 91
5.1.4 Earthing conditions . 91
5.1.5 General conditions for tests . 91
5.1.6 Compliance . 93
5.1.7 Test overview . 93
5.2 Test specifications . 95
5.2.1 Visual inspections (type test, sample test and routine test) . 95
5.2.2 Mechanical tests . 96
5.2.3 Electrical tests . 100
5.2.4 Abnormal operation and simulated faults tests . 119
5.2.5 Material tests . 127
5.2.6 Environmental tests (type tests) . 130
5.2.7 Hydrostatic pressure test (type test and routine test) . 135
6 Information and marking requirements . 135
6.1 General . 135
6.2 Information for selection . 137
6.2.100 Additional marking requirements for SMPS . 138
6.2.101 Additional information for component SMPS . 139

– 4 – IEC 61204-7:2016 EXV  IEC 2016
6.3 Information for installation and commissioning . 139
6.3.1 General . 139
6.3.2 Mechanical considerations . 139
6.3.3 Environment . 140
6.3.4 Handling and mounting . 140
6.3.5 Enclosure temperature. 140
6.3.6 Connections . 140
6.3.7 Protection requirements . 142
6.3.8 Commissioning . 144
6.4 Information for use . 144
6.4.1 General . 144
6.4.2 Adjustment . 144
6.4.3 Labels, signs and signals . 144
6.5 Information for maintenance . 146
6.5.1 General . 146
6.5.2 Capacitor discharge . 147
6.5.3 Auto restart/bypass connection . 147
6.5.4 Other hazards . 147
6.5.5 Equipment with multiple sources of supply . 147
6.5.100 Disconnect device external to permanently connected equipment . 147
6.5.101 Power cord acting as disconnecting device . 148
7 Components . 148
7.1 General . 148
7.2 Switches . 149
7.2.1 General . 149
7.2.2 Requirements for switches acting as disconnecting device . 149
7.2.3 Requirements for switches . 150
7.2.4 Test method and compliance criteria . 151
7.3 Overtemperature protection devices (thermal cut-offs or thermal links) . 151
7.4 PTC thermistors . 151
7.5 Overcurrent protective devices . 152
7.6 Protective devices not mentioned in 7.2 to 7.5 . 152
7.6.1 Other protective devices requirements . 152
7.6.2 Compliance and test method. 152
7.7 Transformers . 152
7.7.1 General . 152
7.7.2 Insulation . 152
7.8 Motors . 153
7.9 Mains supply cords . 154
7.9.1 General . 154
7.9.2 Fitting of non-detachable mains supply cords . 155
7.10 Surge protective devices (SPDs) . 157
7.10.1 Use of an SPD connected to reliable earthing . 157
7.10.2 Use of an SPD between mains and protective earth . 157
7.10.3 Bridging of supplementary, double or reinforced insulation by a SPD . 157
7.10.4 Circuits or components used as transient voltage limiting devices . 157
7.11 Wound components . 158
7.12 IC current limiters . 158
7.12.1 General . 158

7.12.2 Test program 1 . 159
7.12.3 Test program 2 . 159
7.12.4 Test program 3 . 159
7.13 Capacitors and RC units bridging insulation . 160
7.14 Optocouplers bridging insulation . 162
7.15 Relays . 162
7.16 Electrolytic capacitors . 163
Annex A (normative) Additional information for protection against electric shock . 164
Annex B (informative) Considerations for the reduction of the pollution degree . 170
Annex C (informative) Symbols referred to in IEC 62477-1 . 171
Annex D (normative) Evaluation of clearance and creepage distances . 173
Annex E (informative) Altitude correction for clearances . 180
Annex F (normative) Clearance and creepage distance determination for frequencies
greater than 30 kHz . 181
Annex G (informative) Cross-sections of round conductors . 187
Annex H (informative) Guidelines for RCD compatibility . 188
Annex I (informative) Examples of overvoltage category reduction . 192
Annex J (informative) Burn thresholds for touchable surfaces . 199
Annex K (informative) Table of electrochemical potentials . 202
Annex L (informative) Measuring instrument for touch current measurements . 203
Annex M (informative) Test probes for determining access . 204
Annex AA (normative) Addition Insulated winding wires for use without interleaved
insulation . 207
Annex AB (informative) Minimum and maximum cross-section of copper conductors
suitable for connection to terminals for external conductors . 210
Annex AC (normative) DC power and distribution equipment . 211
Annex AD (informative) Examples of protective measures according to 4.4.1 to 4.4.5
for protection against electrical shock . 226
Bibliography . 228

Figure 4 – Example of a SMPS assembly and its associated protective equipotential
bonding. 40
Figure 5 – Example of a SMPS assembly and its associated protective equipotential
bonding. 41
Figure 6 – Fire enclosure bottom openings below an unenclosed or partially enclosed
fire-hazardous component. 72
Figure 7 – Fire enclosure baffle construction. 73
Figure 8 – Supported and unsupported enclosure parts . 88
Figure 9 – Impact test using a steel ball . 98
Figure 11 – Protective equipotential bonding impedance test for separate unit with
power fed from the SMPS with protection for the power cable . 112
Figure 12 – Protective equipotential bonding impedance test for sub-assembly with
accessible parts and with power fed from the SMPS . 113
Figure 13 – Circuit for high-current arcing test . 127
Figure 14 – Test fixture for hot-wire ignition test . 128
Figure 100 – Electric strength test instrument . 117
Figure 101 – Mandrel . 118

– 6 – IEC 61204-7:2016 EXV  IEC 2016
Figure 102 – Initial position of mandrel . 118
Figure 103 – Final position of mandrel . 118
Figure 104 – Position of metal foil on insulating material . 119
Figure 105 – Determination of arithmetic average temperature . 126
Figure 106 – Detachable mains supply cords and connections . 155
Figure A.1 – Protection by DVC As with protective separation . 164
Figure A.2 – Protection by means of protective impedance . 165
Figure A.3 – Protection by using limited voltages . 166
Figure A.20 – Typical waveform for a.c. working voltage . 166
Figure A.21 – Typical waveform for d.c. working voltage . 167
Figure A.22 – Typical waveform for pulsating working voltage . 167
Figure F.1 – Diagram for dimensioning of clearances . 182
Figure F.2 – Diagram for dimensioning of creepage distances . 184
Figure F.3 – Permissible field strength for dimensioning of solid insulation according
to Equation (1) . 186
Figure H.1 – Flow chart leading to selection of the RCD type upstream of a SMPS . 188
Figure H.2 – Fault current waveforms in connections with power electronic converter
devices . 190
Figure I.1 – Basic insulation evaluation for circuits connected to the origin of the
installation mains supply . 192
Figure I.2 – Basic insulation evaluation for circuits connected to the mains supply . 193
Figure I.3 – Basic insulation evaluation for single and three phase equipment not
permanently connected to the mains supply . 193
Figure I.4 – Basic insulation evaluation for circuits connected to the origin of the
installation mains supply where internal SPDs are used . 193
Figure I.5 – Basic insulation evaluation for circuits connected to the mains supply
where internal SPDs are used . 194
Figure I.6 – Example of protective separation evaluation for circuits connected to the
mains supply where internal SPDs are used . 194
Figure I.7 – Example of protective separation evaluation for circuits connected to the
mains supply where internal SPDs are used . 194
Figure I.8 –Example of protective separation evaluation for circuits connected to the
mains supply where internal SPDs are used . 195
Figure I.9 – Basic insulation evaluation for circuits not connected directly to the mains
supply . 195
Figure I.10 – Basic insulation evaluation for circuits not connected directly to the
supply mains . 195
Figure I.11 – Functional insulation evaluation within circuits affected by external
transients . 196
Figure I.12 – Basic insulation evaluation for circuits both connected and not connected
directly to the mains supply . 196
Figure I.13 – Insulation evaluation for accessible circuit of DVC A . 197
Figure I.14 – PEC with mains and non-mains supply without galvanic separation . 197
Figure I.15 – Transformer (basic) isolated PEC inverter with SPD and transformer to
reduce impulse voltage for functional and basic insulation. . 198
Figure J.1 – Burn threshold spread when the skin is in contact with a hot smooth
surface made of bare (uncoated) metal . 199

Figure J.2 – Rise in the burn threshold spread from Figure J.1 for metals which are
coated by shellac varnish of a thickness of 50 µm, 100 µm and 150 µm . 200
Figure J.3 – Rise in the burn threshold spread from Figure J.1 for metals coated with
the specific materials . 200
Figure J.4 – Burn threshold spread when the skin is in contact with a hot smooth
surface made of ceramics, glass and stone materials . 201
Figure J.5 – Burn threshold spread when the skin is in contact with a hot smooth
surface made of plastics . 201
Figure K.1 – Electrochemical potentials (V) . 202
Figure M.1 – Sphere 50 mm probe (IPXXA) . 204
Figure M.2 – Jointed test finger (IPXXB) . 205
Figure M.3 – Test rod 2,5 mm (IP3X) . 206
Figure AC.100 – Resistance and short circuit calculations . 214

Table 1 – Environmental tests . 131
Table 5 – Voltage limits . 36
Table 6 – Separation requirements for circuit under consideration . 37
Table 7 – PE conductor cross-section . 42
Table 8 – Definitions of pollution degrees . 49
Table 9 – Impulse withstand voltage and temporary overvoltage versus system voltage . 51
Table 10 – Clearance distances for functional, basic or supplementary insulation . 58
Table 11 – Creepage distances (in millimetres) . 60
Table 12 – Generic materials for the direct support of uninsulated live parts . 62
Table 13 – Permitted openings in fire enclosure bottoms . 73
Table 14 – Maximum measured total temperatures for internal materials and
components . 75
Table 15 – Maximum measured temperatures for accessible parts of the SMPS . 77
Table 16 – Limits for sources without an overcurrent protective device . 78
Table 17 – Limits for power sources with an overcurrent protective device . 79
Table 18 – Environmental service conditions . 82
Table 19 – Wire bending space from terminals to enclosure . 86
Table 20 – Thickness of sheet metal for enclosures: carbon steel or stainless steel . 89
Table 21 – Thickness of sheet metal for enclosures: aluminium, copper or brass . 90
Table 22 – Test overview . 94
Table 23 – Pull values for handles and manual control securement . 99
Table 24 – Impulse voltage test . 101
Table 25 – Impulse test voltage . 102
Table 26 – AC or d.c. test voltage for circuits connected directly to mains supply . 103
Table 27 – A.c. or d.c. test voltage for circuits connected to non-mains supply without
temporary overvoltages. 104
Table 28 – Partial discharge test . 107
Table 29 – Test duration for protective equipotential bonding test . 114
Table 31 – Dry heat test (steady state) . 132
Table 32 – Damp heat test (steady state) . 133
Table 33 – Vibration test . 134

– 8 – IEC 61204-7:2016 EXV  IEC 2016
Table 34 – Salt mist test . 134
Table 35 – Dust and sand test . 135
Table 36 – Information requirements . 136
Table 100 – Limits for access of current . 47
Table 101 – Tests for insulation in non-separable layers . 64
Table 102 – Temperature limits for transformer windings . 125
Table 103 – Component requirements . 148
Table 104 – Peak surge current . 151
Table 105 – Strain relief test force . 156
Table 106 – Capacitor ratings according to IEC 60384-14 . 161
Table A.4 – Examples for protection against electrical shock . 169
Table C.1 – Symbols used . 171
Table C.100 – Symbols . 172
Table D.1 – Width of grooves by pollution degree . 173
Table E.1 – Correction factor for clearances at altitudes between 2 000 m and
20 000 m . 180
Table E.2 – Test voltages for verifying clearances at different altitudes . 180
Table F.1 – Minimum values of clearances in air at atmospheric pressure for
inhomogeneous field conditions (Table 1 of IEC 60664-4:2005) . 183
Table F.2 – Multiplication factors for clearances in air at atmospheric pressure for
approximately homogeneous field conditions . 183
Table F.3 – Minimum values of creepage distances for different frequency ranges
(Table 2 of IEC 60664-4:2005) . 185
Table G.1 – Standard cross-sections of round conductors. 187
Table AA.1 – Mandrel diameter . 208
Table AA.2 – Oven temperature . 208
Table AB.1 – Cross-section of copper conductors suitable for connection to terminals
for external conductors (extract from IEC 61439-1:2011) . 210
Table AC.101 – AC and DC field wiring spacings . 218
Table AC.102 – Minimum acceptable spacings for uninsulated bus bars . 219
Table AC.103 – Temperature limits . 220
Table AC.104 – Switch test sequences . 222

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCH MODE POWER SUPPLIES –

Part 7: Safety requirements
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.
DISCLAIMER
This Extended version is intended only to provide the user with a comprehensive
content consisting of a product standard and its reference document. An Extended
version is not an official IEC Standard. Only the current versions of the related
standards are to be considered the official documents.
This Extended version of IEC 61204-7:2016 includes the provisions of the general rules
dealt with in IEC 62477-1:2012. Clauses and subclauses of IEC 62477-1:2012 that are
applicable in IEC 61204-7:2016 have been introduced in the content in red text.
International Standard IEC 61204-7 has been prepared by subcommittee 22E: Stabilized
power supplies, of IEC technical committee 22: Power electronic systems and equipment.
This second edition cancels and replaces the first edition published in 2006. This edition
constitutes a complete technical revision.

– 10 – IEC 61204-7:2016 EXV  IEC 2016
This edition includes the following significant technical changes with respect to the previous
edition:
a) use of IEC 62477-1 as reference document, instead of IEC 60950-1;
b) modification of the title by deleting the wording “DC output-“ and adding “switch mode”.
IEC 61204-7 has the
...

IEC 61204-7 ®
Edition 2.0 2016-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switch mode power supplies –
Part 7: Safety requirements
Alimentations à découpage basse tension –
Partie 7: Exigences de sécurité

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 15 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient 20 000 termes et définitions en anglais
Spécifications techniques, Rapports techniques et autres
et en français, ainsi que les termes équivalents dans 15
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
65 000 entrées terminologiques électrotechniques, en anglais
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, et en français, extraites des articles Termes et Définitions des
comité d’études,…). Elle donne aussi des informations sur les publications IEC parues depuis 2002. Plus certaines entrées
projets et les publications remplacées ou retirées. antérieures extraites des publications des CE 37, 77, 86 et

CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC 61204-7 ®
Edition 2.0 2016-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switch mode power supplies –

Part 7: Safety requirements
Alimentations à découpage basse tension –

Partie 7: Exigences de sécurité

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.200 ISBN 978-2-8322-3670-3

– 2 – IEC 61204-7:2016  IEC 2016
CONTENTS
FOREWORD . 7
INTRODUCTION . 10
0 Principles of safety . 11
0.1 General . 11
0.2 Hazards . 12
0.2.1 General . 12
0.2.2 Electric shock . 12
0.2.3 Energy related hazards . 13
0.2.4 Fire . 13
0.2.5 Heat related hazards . 14
0.2.6 Mechanical hazards . 14
0.2.7 Chemical hazards . 14
0.3 Materials and components . 14
1 Scope . 15
1.1 Equipment covered by this document . 15
1.2 Exclusions . 15
1.3 Additional requirements . 15
2 Normative references . 16
3 Terms and definitions . 17
3.100 General . 18
4 Protection against hazards . 20
4.1 General . 20
4.1.100 Constructions not specifically covered . 21
4.1.101 Orientation during transport and use . 21
4.2 Fault and abnormal conditions . 21
4.2.100 Application of faults and abnormal conditions . 22
4.3 Short circuit and overload protection . 22
4.4 Protection against electric shock . 23
4.4.1 General . 23
4.4.2 Decisive voltage class . 23
4.4.3 Provision for basic protection . 25
4.4.4 Provision for fault protection . 26
4.4.5 Enhanced protection . 27
4.4.6 Protective measures . 30
4.4.7 Insulation . 31
4.4.8 Compatibility with residual current-operated protective devices (RCD) . 37
4.4.9 Capacitor discharge . 37
4.5 Protection against electrical energy hazards . 38
4.5.1 Operator access areas. 38
4.5.2 Service access areas . 38
4.6 Protection against fire and thermal hazards . 38
4.6.1 Circuits representing a fire hazard . 38
4.6.2 Components representing a fire hazard . 38
4.6.3 Fire enclosures . 38
4.6.4 Temperature limits . 40
4.6.5 Limited power sources . 41

4.7 Protection against mechanical hazards . 41
4.7.1 General . 41
4.7.2 Specific requirements for liquid cooled SMPS . 41
4.8 Equipment with multiple sources of supply . 41
4.9 Protection against environmental stresses . 41
4.10 Protection against sonic pressure hazards . 41
4.11 Wiring and connections . 41
4.11.1 General . 41
4.11.2 Routing . 41
4.11.3 Colour coding . 41
4.11.4 Splices and connections . 41
4.11.5 Accessible connections . 41
4.11.6 Interconnections between parts of the SMPS . 42
4.11.7 Supply connections. 42
4.11.8 Terminals . 42
4.12 Enclosures . 42
4.12.1 General . 42
4.12.2 Handles and manual controls . 42
4.12.3 Cast metal . 43
4.12.4 Sheet metal . 43
4.12.5 Stability test for enclosure . 43
5 Test requirements . 43
5.1 General . 43
5.1.1 Test objectives and classification . 43
5.1.2 Selection of test samples . 43
5.1.3 Sequence of tests . 43
5.1.4 Earthing conditions . 43
5.1.5 General conditions for tests . 43
5.1.6 Compliance . 44
5.1.7 Test overview . 44
5.2 Test specifications . 46
5.2.1 Visual inspections (type test, sample test and routine test) . 46
5.2.2 Mechanical tests . 46
5.2.3 Electrical tests . 48
5.2.4 Abnormal operation and simulated faults tests . 56
5.2.5 Material tests . 61
5.2.6 Environmental tests (type tests) . 61
5.2.7 Hydrostatic pressure test (type test and routine test) . 62
6 Information and marking requirements . 62
6.1 General . 62
6.2 Information for selection . 64
6.2.100 Additional marking requirements for SMPS . 64
6.2.101 Additional information for Component SMPS . 66
6.3 Information for installation and commissioning . 66
6.3.1 General . 66
6.3.2 Mechanical considerations . 66
6.3.3 Environment . 66
6.3.4 Handling and mounting . 66
6.3.5 Enclosure temperature. 66

– 4 – IEC 61204-7:2016  IEC 2016
6.3.6 Connections . 66
6.3.7 Protection requirements . 67
6.3.8 Commissioning . 69
6.4 Information for use . 69
6.4.1 General . 69
6.4.2 Adjustment . 69
6.4.3 Labels, signs and signals . 69
6.5 Information for maintenance . 69
6.5.1 General . 69
6.5.2 Capacitor discharge . 69
6.5.3 Auto restart/bypass connection . 69
6.5.4 Other hazards . 69
6.5.5 Equipment with multiple sources of supply . 69
6.5.100 Disconnect device external to permanently connected equipment . 70
6.5.101 Power cord acting as disconnecting device . 70
7 Components . 70
7.1 General . 70
7.2 Switches . 71
7.2.1 General . 71
7.2.2 Requirements for switches acting as disconnecting device . 71
7.2.3 Requirements for switches . 72
7.2.4 Test method and compliance criteria . 73
7.3 Overtemperature protection devices (thermal cut-offs or thermal links) . 73
7.4 PTC thermistors . 74
7.5 Overcurrent protective devices . 74
7.6 Protective devices not mentioned in 7.2 to 7.5 . 74
7.6.1 Other protective devices requirements . 74
7.6.2 Compliance and test method. 74
7.7 Transformers . 74
7.7.1 General . 74
7.7.2 Insulation . 75
7.8 Motors . 76
7.9 Mains supply cords . 76
7.9.1 General . 76
7.9.2 Fitting of non-detachable mains supply cords . 77
7.10 Surge Protective Devices (SPDs) . 79
7.10.1 Use of an SPD connected to reliable earthing . 79
7.10.2 Use of an SPD between mains and protective earth . 79
7.10.3 Bridging of supplementary, double or reinforced insulation by a SPD . 79
7.10.4 Circuits or components used as transient voltage limiting devices . 79
7.11 Wound components . 80
7.12 IC current limiters . 80
7.12.1 General . 80
7.12.2 Test program 1 . 81
7.12.3 Test program 2 . 81
7.12.4 Test program 3 . 81
7.13 Capacitors and RC units bridging insulation . 82
7.14 Optocouplers bridging insulation . 84
7.15 Relays . 84

7.16 Electrolytic capacitors . 85
Annex A (normative) Additional information for protection against electric shock . 86
Annex B (informative) Considerations for the reduction of the pollution degree . 88
Annex C (informative) Symbols referred to in IEC 62477-1 . 89
Annex D (normative) Evaluation of clearance and creepage distances . 90
Annex E (informative) Altitude correction for clearances . 91
Annex F (normative) Clearance and creepage distance determination for frequencies
greater than 30 kHz . 92
Annex G (informative) Cross-sections of round conductors . 93
Annex H (informative) Guidelines for RCD compatibility . 94
Annex I (informative) Examples of overvoltage category reduction . 95
Annex J (informative) Burn thresholds for touchable surfaces . 96
Annex K (informative) Table of electrochemical potentials . 97
Annex L (informative) Measuring instrument for touch current measurements . 98
Annex M (informative) Test probes for determining access . 99
Annex AA (normative) Addition Insulated winding wires for use without interleaved
insulation . 100
Annex AB (informative) Minimum and maximum cross-section of copper conductors
suitable for connection to terminals for external conductors . 103
Annex AC (normative) DC power and distribution equipment . 104
Annex AD (informative) Addition Examples of protective measures according to
IEC 61204-7 clause 4.4.1 – 4.4.5 for protection against electrical shock . 119
Bibliography . 121

Figure 100 – Electric strength test instrument . 53
Figure 101 – Mandrel . 54
Figure 102 – Initial position of mandrel . 55
Figure 103 – Final position of mandrel . 55
Figure 104 – Position of metal foil on insulating material . 55
Figure 105 – Determination of arithmetic average temperature . 60
Figure 106 – Detachable mains supply cords and connections . 77
Figure AC.100 – Resistance and short circuit calculations . 107

Table 5 – Voltage limits . 24
Table 6 – Separation requirements for circuit under consideration . 25
Table 100 – Limits for access of current . 29
Table 101 – Tests for insulation in non-separable layers . 36
Table 22 – Test overview . 45
Table 102 – Temperature limits for transformer windings . 60
Table 36 – Information requirements . 63
Table 103 – Component requirements . 71
Table 104 – Peak surge current . 73
Table 105 – Strain relief test force . 78
Table 106 – Capacitor ratings according to IEC 60384-14 . 83

– 6 – IEC 61204-7:2016  IEC 2016
Table C.100 – Symbols . 89
Table AA.1 – Mandrel diameter . 101
Table AA.2 – Oven temperature . 101
Table AB.1 – Cross-section of copper conductors suitable for connection to terminals
for external conductors (extract from IEC 61439-1) . 103
Table AC.101 – AC and DC field wiring spacings . 111
Table AC.102 – Minimum acceptable spacings for uninsulated bus bars . 112
Table AC.103 – Temperature limits . 113
Table AC.104 – Switch test sequences . 115

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCH MODE POWER SUPPLIES –

Part 7: Safety requirements
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 61204-7 has been prepared by subcommittee 22E: Stabilized
power supplies, of IEC technical committee 22: Power electronic systems and equipment.
This second edition cancels and replaces the first edition published in 2006. This edition
constitutes a complete technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) use of IEC 62477-1 as reference document, instead of IEC 60950-1;
b) modification of the title by deleting the wording “DC output-“ and adding “switch mode”.
IEC 61204-7 has the status of a product standard.

– 8 – IEC 61204-7:2016  IEC 2016
The text of this document is based on the following documents:
FDIS Report on voting
22E/175/FDIS 22E/177/RVD
Full information on the voting for the approval of this document can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61204 series, published under the general title Low-voltage power
supplies, d.c. output, can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
This International Standard is to be read in conjunction with IEC 62477-1:2012.
NOTE A consolidated version is under consideration.
The provisions of the general rules dealt with in IEC 62477-1:2012 are only applicable to this
document insofar as they are specifically cited. Clauses and subclauses of IEC 62477-1:2012
that are applicable in this document are identified by reference to the reference document, for
example, 4.3 of IEC 62477-1:2012.
Subclauses that are numbered starting from 100 are additional to those in IEC 62477-1:2012.
Additional tables and figures in this document are numbered starting from 100.
New annexes in this document are lettered AA, AB, AC, etc.
Wherever the word PECS (power electronic converter system) occurs in this reference
document, this means SMPS.
The wordings SMPS and "power supply" are considered to be identical throughout this
document.
References of the reference document to clauses or tables, which have been modified in this
document, shall be read as reference to the relevant clauses or tables of this document.
Refer to 3.100 for further information on how to read this document.
In this document, the following print types are used:
– Requirements proper and normative annexes: in roman type.
– Notes and other informative matter: in smaller roman type.
– Normative conditions within tables: in smaller roman type.
– Terms that are defined in clause 3 or IEC 62477-1:2012: Bold Italic.

The committee has decided that the contents of this 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.
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.
– 10 – IEC 61204-7:2016  IEC 2016
INTRODUCTION
IEC 62477-1:2012, used by this document as a reference, relates to products that include
power electronic converters, with a rated system voltage not exceeding 1 000 V AC or
1 500 V DC. It specifies requirements to reduce risks of fire, electric shock, thermal, energy
and mechanical hazards, except functional safety as defined in IEC 61508 (all parts). The
objectives of this standard are to establish a common terminology and basis for the safety
requirements of products that contain power electronic converters across several
IEC technical committees.
IEC 62477-1:2012 was developed with the intention
• to be used as a reference document for product committees inside IEC technical
committee 22: Power electronic systems and equipment in the development of product
standards for power electronic converter systems and equipment,
• to replace IEC 62103 as a product family standard providing minimum requirements for
safety aspects of power electronic converter systems and equipment in apparatus for
which no product standard exists, and
NOTE The scope of IEC 62103 contains reliability aspects, which are not covered by this document.
• to be used as a reference document for product committees outside TC 22 in the
development of product standards of power electronic converter systems and equipment
intended for renewable energy sources. TC 82, TC 88, TC 105 and TC 114, in particular,
have been identified as relevant technical committees at the time of publication.
As such, IEC technical sub-committee 22E: Stabilized switched-mode power supplies
carefully considered the relevance of each paragraph of IEC 62477-1:2012 for the SMPS and
referenced, added, replaced or modified requirements as relevant. This is because product-
specific topics not covered by the reference document are the responsibility of the technical
committee using the reference document.
The reference document, being a group safety standard, will not take precedence over this
product-specific standard according to IEC Guide 104. IEC Guide 104 provides information
about the responsibility of product committees to use group safety standards for the
development of their own product standards.

LOW-VOLTAGE SWITCH MODE POWER SUPPLIES –

Part 7: Safety requirements
0 Principles of safety
Safety principles of this document follow the concepts of IEC Guide 116 and Annex D of
CENELEC Guide 32:2014.
NOTE The principles of safety are mainly adopted from IEC 60950-1:2005/AMD1:2009/AMD2:2013.
0.1 General
The following principles have been adopted by IEC technical committee 22E in the
development of this document. These principles do not cover performance or functional
characteristics of equipment.
It is essential that designers understand the underlying principles of safety requirements in
order that they can engineer safe equipment.
These principles are not an alternative to the detailed requirements of this document, but are
intended to provide designers with an appreciation of the basis of these requirements. Where
the equipment involves technologies, components and materials or methods of construction
not specifically covered, the design of the equipment should provide a level of safety not less
than that described in these principles of safety.
NOTE The need for additional detailed requirements to cope with a new situation is brought promptly to the
attention of the appropriate committee.
Designers will take into account not only normal operating conditions of the equipment but
also likely fault conditions, consequential faults, foreseeable misuse and external influences
such as temperature, altitude, pollution, moisture, overvoltages on the mains supply and
non-mains supply.
Dimensioning of insulation spacings should take account of possible reductions by
manufacturing tolerances, or where deformation could occur due to handling, shock and
vibration likely to be encountered during manufacture, transport and normal operation.
The following priorities should be observed in determining what design measures to adopt:
– where possible, specify design criteria that will eliminate, reduce or guard against
hazards;
– where the above is not practicable because the functioning of the equipment would be
impaired, specify the use of protective means independent of the equipment, such as
personal protective equipment (which is not specified in this document);
– where neither of the above measures is practicable, or in addition to those measures,
specify the provision of markings and instructions regarding the residual risks.
There are two types of persons whose safety needs to be considered, operators (or users)
and service persons.
Operator is the term applied to all persons other than service persons. Requirements for
protection should assume that operators are not trained to identify hazards, but will not
intentionally create a hazardous situation. Consequently, the requirements will provide
protection for cleaners and casual visitors as well as the assigned operators. In general,

– 12 – IEC 61204-7:2016  IEC 2016
operators should not have access to hazardous parts, and to this end, such parts should only
be in service access area or in equipment located in restricted access areas.
When operators are admitted to restricted access areas (RAA) they shall be suitably
instructed.
NOTE The term "restricted access area" (RAA) is also known as "restricted access location" (RAL).
Service persons are expected to use their training and skill to avoid possible injury to
themselves and others due to obvious hazards that exist in service access areas of the
equipment or on equipment located in restricted access areas. However, service persons
should be protected against unexpected hazards. This can be done by, for example, locating
parts that need to be accessible for servicing away from electrical and mechanical hazards,
providing shields to avoid accidental contact with hazardous parts, and providing labels or
instructions to warn personnel about any residual risk.
Information about potential hazards can be marked on the equipment or provided with the
equipment, depending on the likelihood and severity of injury, or made available for service
persons. In general, operators shall not be exposed to hazards likely to cause injury, and
information provided for operators should primarily aim at avoiding misuse and situations
likely to create hazards, such as connection to the wrong power source and replacement of
fuses by incorrect types.
Moveable equipment is considered to present a slightly increased risk of shock, due to
possible extra strain on the supply cord leading to rupture of the earthing conductor. With
hand-held equipment, this risk is increased; wear on the cord is more likely, and further
hazards could arise if the units were dropped. Transportable equipment introduces a further
factor because it can be used and carried in any orientation; if a small metallic object enters
an opening in the enclosure, it can move around inside the equipment, possibly creating a
hazard.
0.2 Hazards
0.2.1 General
Application of a safety standard is intended to reduce the risk of injury or damage due to the
following:
– electric shock;
– energy related hazards;
– fire;
– heat related hazards;
– mechanical hazards;
– chemical hazards.
NOTE Radiation hazard are not included, as LEDs used for the purpose of indication and display only are not
considered to cause hazardous radiation (e.g. like high intense lighting LEDs).
0.2.2 Electric shock
Electric shock is due to current passing through the human body. The resulting physiological
effects depend on the value and duration of the current and the path i
...