Iec TR 62296-2009

IEC/TR 62296
®
Edition 2.0 2009-01
TECHNICAL
REPORT
FOR INTERNAL USE AT THIS LOCATION ONLY, SUPPLIED BY BOOK SUPPLY BUREAU.
LICENSED TO MECON Limited. - RANCHI/BANGALORE
Considerations of unaddressed safety aspects in the second edition of
IEC 60601-1 and proposals for new requirements
IEC/TR 62296:2009(E)
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IEC/TR 62296
®
Edition 2.0 2009-01
TECHNICAL
REPORT
Considerations of unaddressed safety aspects in the second edition of
IEC 60601-1 and proposals for new requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION PRICE CODE
XC
ICS 11.040 ISBN 2-8318-1025-1
® Registered trademark of the International Electrotechnical Commission

–2– TR 62296 © IEC:2009(E)
CONTENTS
FOREWORD...........................................................................................................................4
INTRODUCTION.....................................................................................................................6
1 Scope and object..............................................................................................................7
1.1 Scope......................................................................................................................7
1.2 Object .....................................................................................................................7
2 Recommendations ............................................................................................................7
2.1 Summary of all recommendations prepared by SC 62A/WG 14 ................................ 7
2.2 Recommendation sheets ....................................................................................... 10
2.2.1 Separation: Reliability of component impedance ........................................ 10
2.2.2 Separation: Non-complying creepage distance and air clearances ............. 12
2.2.3 Mains supply transformers: Overload test .................................................. 13
2.2.4 Mains supply transformers: Short circuit and overload tests....................... 14
2.2.5 Creepage distance and air clearances: Values .......................................... 15
2.2.6 Dielectric strength ..................................................................................... 16
2.2.7 Failure of components: Evidence of reliability ............................................ 17
2.2.8 E NCLOSURES and protective covers ............................................................ 18
2.2.9 I NTERNALLY POWERED EQUIPMENT : 110 % of the maximum supply
voltage ...................................................................................................... 19
2.2.10 Creepage distances and air clearances: Values under 1 mm ..................... 20
2.2.11 Separation: Secondary circuit impedance limit LEAKAGE CURRENT ............... 21
2.2.12 E NCLOSURES and PROTECTIVE COVERS : Lampholder/switching device.......... 22
2.2.13 Fixing, prevention of maladjustment: Torque test ....................................... 23
2.2.14 Batteries not intended to be changed by OPERATOR : Lithium batteries ........ 24
2.2.15 Excessive temperatures: Ambient temperatures ........................................ 25
2.2.16 Continuous LEAKAGE CURRENTS : Different SUPPLY MAINS ............................. 26
2.2.17 E NCLOSURE and protective covers: EQUIPMENT in ambulances .................... 27
2.2.18 Dielectric strength: Voltages appearing from external sources ................... 28
2.2.19 Testing switch mode power supply units (SMPSU)..................................... 29
2.2.20 Failure of an electrical component: Time periodicity for detection .............. 30
2.2.21 Environmental conditions: Compliance paragraph...................................... 31
2.2.22 Limitation of voltage and/or energy: Capacitance....................................... 32
2.2.23 L EAKAGE CURRENTS : Presence of 45 kΩ resistor in Figure 21 ..................... 33
2.2.24 Humidity preconditioning treatment: Exception from requirement ............... 34
2.2.25 Dielectric strength: E QUIPMENT containing floating circuits ......................... 35
2.2.26 General requirements for tests: Measurement uncertainty ......................... 36
2.2.27 C REEPAGE DISTANCES and AIR CLEARANCES : Interpolated values.................. 37
2.2.28 Overheating: Change of load resistance .................................................... 38
2.2.29 Mains operated EQUIPMENT with additional power source: Integrity of
external protective earth ............................................................................ 39
2.2.30 Rechargeable batteries: No OPERATOR / USER maintenance ......................... 40
2.2.31 Isolation from the SUPPLY MAINS : Symbol for single pole switch .................. 41
2.2.32 Sequence of testing: Clause 52 before Clause 19...................................... 42
2.2.33 S INGLE FAULT CONDITION : E NCLOSURE LEAKAGE CURRENT from
INTERNALLY POWERED EQUIPMENT ................................................................ 43
2.2.34 Marking on the outside of EQUIPMENT : Type and rating of fuses ................. 44
2.2.35 Excessive temperatures: A PPLIED PARTS not intended to supply heat ......... 45
2.2.36 Mains supply transformers: Use of PTCs as protective devices ................. 46
TR 62296 © IEC:2009(E) –3–
2.2.37Components and general assembly: Reliability of components .................. 47

2.2.38Definition of APPLIED PART : E QUIPMENT worn by PATIENTS ........................... 48
2.2.39Construction: Triple insulated winding wire ................................................ 49
2.2.40C REEPAGE DISTANCES and AIR CLEARANCES : Dielectric strength test
versus CREEPAGE DISTANCES and AIR CLEARANCES ...................................... 50
2.2.41 C REEPAGE DISTANCES and AIR CLEARANCES : Dielectric strength test
versus CREEPAGE DISTANCES and AIR CLEARANCES – POWER SUPPLY
CORDS ........................................................................................................ 51
2.2.42 A CCOMPANYING DOCUMENTS : on CD-ROM or electronic file format .............. 52
2.2.43 I NTERNAL ELECTRICAL POWER SOURCE : Requirements for lithium
batteries .................................................................................................... 53
2.2.44 Dielectric strength: Differences between B-d and B-e ................................ 54
2.2.45 Excessive temperatures: Thermocouple instead of resistance method ....... 55
2.2.46 Mains fuses and OVER - CURRENT RELEASE s: Fuses in CLASS II
EQUIPMENT ................................................................................................. 56
2.2.47 Plug in power supply ................................................................................. 57
2.2.48 Connecting cords between EQUIPMENT parts: Other applications ................ 58
2.2.49 M ULTIPLE PORTABLE SOCKET - OUTLET ............................................................ 59
2.2.50 Separation, D EFIBRILLATION - PROOF APPLIED PART : multiple APPLIED
PARTS ........................................................................................................ 60
2.2.51 Separation, APPLIED PART : Hand held flexible shafts................................... 61
2.2.52 Protective earthing: No-load voltage of 6 V maximum ................................ 62
2.2.53 Foot-operated control devices: Protection against entry of liquids.............. 63
2.2.54 Mains supply transformers ......................................................................... 64
2.2.55 Dielectric strength: Reliability of components to bridge A-a2 and B-a ......... 65
2.2.56 Dielectric strength: A-e in switch mode power supply units (SMPSU) ......... 66
2.2.57 Dielectric strength: Connection of 12 V dc negative side to
ENCLOSURE ................................................................................................ 67
2.2.58 Dielectric strength: Voltages appearing on SIP / SOP .................................... 68
2.2.59 A PPLIED PART : E QUIPMENT without APPLIED PART ......................................... 69
2.2.60 Scope: Other than MEDICAL ELECTRICAL EQUIPMENT in contact with the
body of a person........................................................................................ 70
2.2.61 Markings: AC symbol ................................................................................. 71
2.2.62 Interruption of power supply: Characteristics of interruption....................... 72
2.2.63 Reference voltage: Different reference voltages in the same circuit ........... 73
Bibliography.......................................................................................................................... 74
Index of Terms...................................................................................................................... 76
–4– TR 62296 © IEC:2009(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
CONSIDERATIONS OF UNADDRESSED SAFETY ASPECTS

IN THE SECOND EDITION OF IEC 60601-1 AND
PROPOSALS FOR NEW 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-
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agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62296, which is a technical report, has been prepared by subcommittee 62A: Common
aspects of electrical equipment used in medical practice, of IEC technical committee 62:
Electrical equipment in medical practice.
This second edition cancels and replaces the first edition published in 2003. It constitutes a
technical revision. This edition includes seven new recommendations: Recommendations 57
through 63. As the third edition of IEC 60601-1 has been published, some of the
recommendations in this edition have been changed to align with requirements in
IEC 60601-1:2005.
TR 62296 © IEC:2009(E) –5–
The text of this technical report is based on the following documents:
Enquiry draft Report on voting

62A/621/DTR 62A/632/RVC
Full information on the voting for the approval of this technical report 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.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the
data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this technical report may be issued at a later date.

–6– TR 62296 © IEC:2009(E)
INTRODUCTION
At the Sydney meeting in August 1994, IEC subcommittee (SC) 62A established a procedure
under which working group (WG) 14 would develop recommendations regarding problems of
interpretation or application of IEC 60601-1. WG 14 is made up of experts with particular
expertise in testing according to the requirements of IEC 60601-1. Many of the experts on WG
14 are employed by test houses with a long history of applying IEC 60601-1 to MEDICAL
ELECTRICAL EQUIPMENT . While the National Committee members of SC 62A nominate these
experts, their recommendations were not to be formally adopted through any official voting
procedure. To reinforce this process, the Subcommittee specifically directed that the following
note appear on every page of the resulting informational circular:
IMPORTANT NOTE: Per the 62A decision at Sydney (see RM3755/SC62A,

August 1994), the 62A Secretary is circulating this recommendation, prepared
by 62A/WG14, regarding problems of interpretation or application of
IEC 60601-1 to all P-Member NC’s.
This recommendation/interpretation is the result of considerations by a group

of nominated experts and has not been formally adopted through any NC
voting procedure. Distribution is only for information.
The plan approved in Sydney called for the 62A Secretary to circulate these recommendations
to the member National Committees via an informational (INF) document.
While the quality of the technical work of WG 14 is widely recognized and applauded, the
overall process has achieved less than originally hoped. The INF documents have not proved
a particularly successful way of getting this information to those who could use it most. The
WG 14 recommendations are largely unknown beyond the people actively involved in the work
of SC 62A. Several alternatives have been explored. These include making the individual
recommendation sheets available on the Internet either through the IEC Web Site, the web
site of a participating National Committee, or the web site of an interested third party.
However, concerns over intellectual property and control of distribution have proved extremely
difficult to overcome.
At the November 2000 meeting of SC 62A in Tokyo, the subcommittee discussed ways and
means for achieving a wider distribution of the WG 14 recommendations. At the conclusion of
this discussion, the subcommittee instructed the Secretariat to develop a technical report (TR)
based on the published recommendations of WG 14. This technical report is intended to
convey the results of WG 14's work to interested parties such as manufacturers and test
houses while retaining the informative nature of the material.
This technical report may be amended from time to time as WG 14 prepares additional
recommendations.
TR 62296 © IEC:2009(E) –7–
CONSIDERATIONS OF UNADDRESSED SAFETY ASPECTS

IN THE SECOND EDITION OF IEC 60601-1 AND
PROPOSALS FOR NEW REQUIREMENTS
1 Scope and object
1.1 Scope
This technical report contains a series of recommendations developed by an expert working

group of IEC subcommittee 62A in response to questions of interpretation of the second
edition of IEC 60601-1.
This technical report is primarily intended to be used by:
– manufacturers of MEDICAL ELECTRICAL EQUIPMENT ;

– test houses and others responsible for assessment of compliance with IEC 60601-1:1988,
and
– those developing subsequent editions of IEC 60601-1.
The recommendations in the first edition of IEC/TR 62296 were considered in preparing the
third edition of IEC 60601-1. As the third edition of IEC 60601-1 has been published, some of
the recommendations in the second edition of IEC/TR 62296 have been changed to align with
requirements in IEC 60601-1:2005. Seven additional recommendations have been developed
by IEC/SC 62A/WG 14 and are included in this edition of IEC/TR 62296. They are
recommendations 57 through 63.
1.2 Object
The object of this technical report is to make the recommendations/interpretations developed

by the experts in IEC/SC 62A/WG 14 available to those interested in the application of the
second edition of IEC 60601-1.
The reader is reminded that, although a majority of the National Committee members of
IEC/SC 62A have approved publication of this technical report, the contents remain the
opinion of the expert members of WG 14. These recommendations/interpretations are the
result of considerations by this group of nominated experts and have not been formally
adopted through any National Committee voting procedure. Distribution is only for
information.
2 Recommendations
2.1 Summary of all recommendations prepared by SC 62A/WG 14

Subclause
Recom-
of the 2 nd
mendation Contents Page
edition of
number
IEC 60601-1
1.1 060 Other than MEDICAL ELECTRICAL EQUIPMENT in contact with the body of a person 70
2.1.5 038 Definition of APPLIED PART : E QUIPMENT worn by PATIENTS 48
2.1.5 059 A PPLIED PART : E QUIPMENT without APPLIED PART 69
3.6 f) 020 Failure of an electrical component: Time periodicity for detection 30
4 026 General requirements for tests: Measurement uncertainty 36
4.10 024 Humidity preconditioning treatment: Exception from requirement 34
–8– TR 62296 © IEC:2009(E)
Subclause
Recom-
of the 2 nd
edition of
number
IEC 60601-1
6.1 g) 061 Markings: AC symbol 71

6.1 n) 034 Marking on the outside of EQUIPMENT : Type and rating of fuses 44
6.2 d) 014 Batteries not intended to be changed by OPERATOR : Lithium batteries 24
6.8.1 042 A CCOMPANYING DOCUMENTS : On CD-ROM or electronic file format 52
6.8.2 e) 029 Mains operated EQUIPMENT with additional power source: Integrity of external 39
protective earth
6.8.2 g) 030 Rechargeable batteries: No OPERATOR / USER maintenance 40
10 021 Environmental conditions: Compliance paragraph 31
15 b) 022 Limitation of voltage and/or energy: Capacitance 32
16 008 E NCLOSURES and protective covers: Accessibility of SIP/SOPs 18
16 017 E NCLOSURE and protective covers: E QUIPMENT in ambulances 27
16 d) 012 E NCLOSURES and PROTECTIVE COVERS : Lampholder/switching device 22
17 a) 002 Separation: Non-complying CREEPAGE DISTANCES and AIR CLEARANCES 12
(Recommendation deleted: text implemented in recommendation No. 1)
17 a)+g) 5) 001 Separation: Reliability of component impedance 10
17 c) 051 Separation, APPLIED PART : Hand-held flexible shafts 61
17 g) 011 Separation: secondary circuit impedance limit LEAKAGE CURRENT 21
(Recommendation deleted: text implemented in recommendation No. 1)
17 h) 050 Separation, DEFIBRILLATION - PROOF APPLIED PART : Multiple APPLIED PARTS 60
18 f) 052 Protective earthing: No-load voltage of 6 V maximum 62
19 023 L EAKAGE CURRENTS : Presence of 45 kΩ resistor in Figure 21 33
19.1 016 Continuous LEAKAGE CURRENTS : Different SUPPLY MAINS 26
19.2 c) 033 S INGLE FAULT CONDITION : E NCLOSURE LEAKAGE CURRENT from INTERNALLY 43
POW ERED EQUIPMENT
19.4 h 7) / 8) 009 Internally powered equipment: 110 % of the maximum supply voltage 19
20.1 A-a1 006 Dielectric strength: Intermediate circuits 16
20.1 A-a1 057 Dielectric strength: Connection of 12 V dc negative side to ENCLOSURE 67
20.1 A-e 056 Dielectric strength: A-e in switch mode power supply units (SMPSU) 66
20.1 A-k 018 Dielectric strength: Voltages appearing from external sources 28
20.1 A-k 058 Dielectric strength: Voltages appearing on SIP / SOP 68
20.2 044 Dielectric strength: Differences between B-d and B-e 54
20.2 055 Dielectric strength: Reliability of components to bridge A-a 2 and B-a 65
20.2 B-e 025 Dielectric strength: EQUIPMENT containing floating circuits 35
20.3 063 Reference voltage: Different reference voltages in the same circuit 73
42.2 015 Excessive temperatures: Ambient temperatures 25
42.3 035 Excessive temperatures: A PPLIED PARTS not intended to supply heat 45
42.3 045 Excessive temperatures: Thermocouple instead of resistance method 55
49 062 Interruption of power supply: Characteristics of interruption 72
52.5.9 007 Failure of components: Evidence of reliability 17
56.1 b) 037 Components and general assembly: reliability of components 47
56.10 b) 013 Fixing, prevention of maladjustment: torque test 23
56.11 d) 053 Foot-operated control devices: protection against entry of liquids 63
56.7 043 I NTERNAL ELECTRICAL POW ER SOURCE : Requirements for lithium batteries 53
TR 62296 © IEC:2009(E) –9–
Subclause
Recom-
of the 2 nd
edition of
number
IEC 60601-1
57.1 a) 031 Isolation from the SUPPLY MAINS : Symbol for single pole switch 41
57.10 027 C REEPAGE DISTANCES and AIR CLEARANCES : Interpolated values 37
57.10 a) 005 C REEPAGE DISTANCES and AIR CLEARANCES : Values for material 15
57.10 d) 010 C REEPAGE DISTANCES and AIR CLEARANCES : Values under 1 mm 20
57.10 d) 040 C REEPAGE DISTANCES and AIR CLEARANCES : Dielectric strength test versus 50
CREEPAGE DISTANCES and AIR CLEARANCES
57.2.201 049 M ULTIPLE PORTABLE SOCKET - OUTLET 59

57.4 a) b) 041 Cord anchorages/ Cord guards: In mobile unit with APPLIANCE COUPLER 51
57.6 046 Mains fuses and OVER - CURRENT RELEASE s: Fuses in CLASS II EQUIPMENT 56
57.9 019 Testing switch mode power supply units (SMPSU) 29
57.9 047 Plug-in power supply 57
57.9 054 Mains supply transformers 64
57.9 b) 036 Mains supply transformers: Use of PTCs as protective devices 46
57.9.1 004 Mains supply transformers: Short circuit and overload tests 14
57.9.1 028 Overheating: Change of load resistance 38
57.9.1 b) 003 Mains supply transformers: Overload test 13
57.9.4 039 Construction: Triple insulated winding wire 49
59.1 f) 048 Connecting cords between EQUIPMENT parts: Other applications 58
Appendix C 032 Sequence of testing: Clause 52 before Clause 19 42
– 10 – TR 62296 © IEC:2009(E)
2.2 Recommendation sheets
2.2.1 Separation: Reliability of component impedance
IEC/SC 62A/WG14 Recommendation No. 1
Problem raised in: SC 62A/WG 14(Canada)1, 2 and 4
Requirement, clause no. 17 Separation

a) A PPLIED PARTS shall be electrically separated from LIVE parts of EQUIPMENT in
NORMAL CONDITION and in SINGLE FAULT CONDITION (see 3.6), in such a way that
allowable LEAKAGE CURRENTS (see Clause 19) are not exceeded.
g) A CCESSIBLE PARTS not being an APPLIED PART shall be electrically separated
from LIVE parts of EQUIPMENT in NORMAL CONDITION and in SINGLE FAULT CONDITION
(see 3.6) in such a way that allowable LEAKAGE CURRENTS are not exceeded (see
Clause 19).
This requirement may be fulfilled by one of the following methods:
17 a 5) Impedances of components prevent the flow to the APPLIED PART of a
PATIENT LEAKAGE CURRENT and PATIENT AUXILIARY CURRENT exceeding the
allowable values.
17 g 5) Impedances of components prevent the flow to the ACCESSIBLE PART of an
ENCLOSURE LEAKAGE CURRENT exceeding the allowable value.
Test clause no. Compliance with items a) and g) of Clause 17 is checked by inspection and
measurement.
If the CREEPAGE DISTANCE and/or AIR CLEARANCE between the APPLIED PART
( ACCESSIBLE PARTS ) and LIVE parts does not comply with the requirements of
57.10, such CREEPAGE DISTANCE and/or AIR CLEARANCE shall be short circuited.
The LEAKAGE CURRENTS are measured as described in 19.4 and shall not exceed
the limits for NORMAL CONDITION given in Table IV.
Source/Problem SC 62A/WG 14(Canada)1
Component impedance is generally unreliable. Can components certified to
IEC 60384-14 etc. be considered as high integrity? Is the impedance of a
component sufficient? Does investigation of the product require further review of
AIR CLEARANCE and CREEPAGE DISTANCE for such a component? Does this
subclause mean that further component review is not required?
SC 62A/WG 14(Canada)2
Assume mains to floating APPLIED PART does not comply with AIR CLEARANCE and
CREEPAGE DISTANCE requirements. Mains to floating APPLIED PART isolation is short
circuited.
SC 62A/WG 14(Canada)4
If secondary circuit impedances limit the LEAKAGE CURRENT , is further investigation
of secondary circuits required? (Refer to 52.5).
Discussion/comment The problem is two-fold. Separation between LIVE PARTS and APPLIED
PARTS / ACCESSIBLE PARTS is dependent on components (protective impedances)
and/or AIR CLEARANCES and CREEPAGE DISTANCES .
Subclause 52.5.9 requires that failure of components shall be investigated and
especially those components which provide protective means.
Subclause 17 requires compliance with the spacings, but if these spacings are
inadequate, they shall be short circuited and LEAKAGE CURRENTS monitored.
Referring to Canada 2, we assume that it refers to inadequate spacings which
need to be short circuited.
Up to now there are no requirements for components to be considered high
integrity, but there are requirements for Y1 and Y2 capacitors.
TR 62296 © IEC:2009(E) – 11 –
WG 14 recommendation If a capacitor (protective impedance) is used, the following applies:

– One Y1 capacitor complying with IEC 60384-14 is considered equivalent to one
MEANS OF PROTECTION provided that it will pass the dielectric strength test for
DOUBLE or REINFORCED INSULATION . Where two capacitors are used in series,
they shall each be RATED for the total W ORKING VOLTAGE across the pair and
shall have the same NOMINAL capacitance.
– Two Y2 capacitors complying with IEC 60384-14 in series are considered
equivalent to ONE MEANS OF PROTECTION provided that each will pass the
dielectric strength test for BASIC INSULATION . Where two capacitors are used in
series, they shall each be RATED for the total W ORKING VOLTAGE across the pair
and shall have the same NOMINAL capacitance.
According to the standard, DOUBLE INSULATION is not to be short circuited. D OUBLE

INSULATION consists of BASIC INSULATION and SUPPLEMENTARY INSULATION , each of
which can be short circuited. Where spacings for DOUBLE INSULATION are
inadequate, these spacings effectively reduce to either BASIC INSULATION or
SUPPLEMENTARY INSULATION . In this case, the whole of the spacing needs to be
short circuited. This is considered to be a SINGLE FAULT CONDITION .
Where the spacings are less than BASIC INSULATION the short circuit of these is
considered a NORMAL CONDITION .
L EAKAGE CURRENT measurements are carried out after applying the above short
circuits.
The secondary circuits and any protective means limiting LEAKAGE CURRENTS must
be investigated under SINGLE FAULT CONDITION .
See also Recommendation No. 20.
– 12 – TR 62296 © IEC:2009(E)
2.2.2 Separation: Non-complying creepage distance and air clearances
Problem raised in: SC 62A/WG 14(Canada)2
Recommendation deleted: text implemented in recommendation No. 1
TR 62296 © IEC:2009(E) – 13 –
2.2.3 Mains supply transformers: Overload test
Requirement, clause no. 57.9.1b) Mains supply transformers: Overload test
Test clause no.
Source/Problem Normal product investigation requires dielectric strength test after transformer
overload test. Does the overload test alone verify that no SAFETY HAZARD exists?
Discussion/comment
WG 14 recommendation The overload test alone verifies that no SAFETY HAZARD exists, but if the integrity
of the insulation is in doubt (regarding temperature limits), a repeated dielectric
strength test should be carried out after the overload test.
– 14 – TR 62296 © IEC:2009(E)
2.2.4 Mains supply transformers: Short circuit and overload tests
Requirement, clause no. 57.9.1 Mains supply transformers: Short circuit and Overload tests.
Test clause no.
Source/Problem Secondary circuit over-current protection is the first active component on the
secondary side of a mains supply transformer. Is the overload test performed
before or after the fuse?
Insufficient transformer winding crossover insulation and secondary circuit
CREEPAGE DISTANCES and AIR CLEARANCES causes transformer winding to short
circuit and exceed allowable temperatures.
Discussion/comment Inspection of the transformer arrangements will be necessary to determine the

likelihood of a short circuit before the over-current protection.
WG 14 recommendation If the possibility of a short circuit exists before the secondary over-current
protection device (e.g. failure of BASIC INSULATION between winding or
detachment of the wiring), the short circuit test should be conducted at the exit of
the wiring from the transformer.
(N.B. Similar recommendations can be made for batteries and their protective
devices.)
The overload test however shall always be conducted after any secondary over-
current protection device providing that the conditions of 57.9.1 second dash are
fulfilled.
TR 62296 © IEC:2009(E) – 15 –
2.2.5 Creepage distance and air clearances: Values
Requirement, clause no. 57.10a) CREEPAGE DISTANCES and AIR CLEARANCES : Values
Test clause no.
Source/Problem There appears no specific means of investigating opto-couplers, multi-layer
printed circuit boards, d.c. to d.c. converters and secondary transformers for
CREEPAGE DISTANCES and AIR CLEARANCES . Can we apply distance through
insulation concepts?
Discussion/comment At present the concept of distance through insulation (e.g. in an opto-coupler or

between a multilayer printed circuit board) is not applied.
WG 14 recommendation There is no additional recommendation to the already required dielectric strength

test.
– 16 – TR 62296 © IEC:2009(E)
2.2.6 Dielectric strength
Problem raised in: Fax from M.M. Stuchi (IMQ)
Requirement, clause no. 20 Dielectric strength.

20.1 A-a1) Between LIVE parts and accessible metal parts which are protectively
earthed.
The insulation shall be BASIC INSULATION .
Test clause no.
Source/Problem This requirement would appear to apply also to intermediate circuits which may
or may not remain LIVE after interruption of the PROTECTIVE EARTH CONDUCTOR .
Should A-a1) be applied also in those cases where the intermediate circuit
ceases to be LIVE after interruption of the PROTECTIVE EARTH CONDUCTOR ?
Discussion/comment Insulation requirements are intended to provide protection for circuits which could
be hazardous in SINGLE FAULT CONDITION .
WG 14 recommendation Requirements for BASIC INSULATION A-a1) should be applied only to those
intermediate circuits which may be hazardous in SINGLE FAULT CONDITION .
A CCESSIBLE PARTS including APPLIED PARTS have to be separated from certain
internal LIVE parts. In general two separate MEANS OF PROTECTION are necessary,
one to provide separation in NORMAL CONDITION and a second to maintain safety
in SINGLE FAULT CONDITION , and LEAKAGE CURRENTS (and possibly also voltages
and energies) have to be below acceptable limits.
TR 62296 © IEC:2009(E) – 17 –
2.2.7 Failure of components: Evidence of reliability
Problem raised in: SC 62A/WG 14(Sweden)13
Requirement, clause no. 52.5 The following SINGLE FAULT CONDITIONS are the subject of specific
requirements and tests.
52.5.9 Failure of components: Failure of one component at a time, which failure
could cause a SAFETY HAZARD as mentioned in 52.4, is simulated.
This requirement and relevant tests shall not be applied to failures of DOUBLE or
REINFORCED INSULATION .
Rationale 57.7: Interference suppressors may be connected on the SUPPLY MAINS

side of an EQUIPMENT mains switch or on the SUPPLY MAINS side of any mains
fuse or OVER - CURRENT RELEASE .
Test clause no.
Source/Problem The Rationale to 57.7 is in contradiction with the requirement in 52.5.9. For
instance, any capacitor connected on the SUPPLY MAINS side of mains fuses
would, in the case of short-circuit fault, imply that the safety depends on safety
devices external to the EQUIPMENT in which the capacitor is mounted.
What shall be required of components connected on the SUPPLY MAINS side of any
mains fuse or OVER - CURRENT RELEASE ? For instance, shall capacitors complying
with IEC 60384-14 be accepted?
Discussion/comment Amendment 2 answers the capacitor problem, however it does not deal with other
components, e.g. discharge resistors.
WG 14 recommendation For these components, compliance with a relevant IEC standard should be
sought. If no suitable standard exists, examination of characteristics and
evidence of reliability should be researched as 3.4 suggests (equivalent degree
of safety).
– 18 – TR 62296 © IEC:2009(E)
2.2.8 E NCLOSURES and protective covers
IEC/SC 62A/WG 14 Recommendation No. 8
Requirement, clause no. 16 E NCLOSURES and protective covers
Test clause no.
Source/Problem In practice, many standard SIP/SOPs are constructed so that LIVE parts of the
SIP/SOPs are accessible with the standard test finger or, alternatively, the AIR
CLEARANCES and/or CREEPAGE DISTANCES between these live parts and the
standard test finger are too short. This means that these LIVE parts of SIP/SOPs
are to be considered as part of the ENCLOSURE and therefore the corresponding
ENCLOSURE LEAKAGE CURRENT shall be measured. As a consequence, many
existing standard SIP/SOPs fail to comply with the standard.
Should, for instance, concession be granted for SIP/SOPs with accessible LIVE
parts with a voltage (to earth) not exceeding 25 V a.c. or 60 V d.c.?
Discussion/comment For the operator, access to parts at potentials not exceeding 25 V a.c. or
60 V d.c. is considered not to present a hazard, provided that simultaneous
contact between operator and patient is avoided.
Probability of simultaneous contact between patient and SIP/SOPs is considered
very low during treatment.
WG 14 recommendation SIP/SOPs with OPERATOR accessible LIVE parts and which are SAFETY EXTRA - LOW
VOLTAGE (SELV) shall be accepted, if the instructions for use instruct the
OPERATOR not to touch such parts and the PATIENT simultaneously.
TR 62296 © IEC:2009(E) – 19 –
2.2.9 I NTERNALLY POWERED EQUIPMENT: 110 % of the maximum supply voltage
Requirement, clause no. 19.4 h) Measurement of PATIENT LEAKAGE CURRENT
Test clause no. 19.4 h) 7) and 8) for INTERNALLY POW ERED EQUIPMENT
Source/Problem Both these tests are required to be conducted at 250 V at the supply frequency.
Discussion/comment SC 62A/WG 14(Sweden)15

Since some INTERNALLY POW ERED EQUIPMENT is provided with a means of connection
to a SUPPLY MAINS , should not these tests be carried out at more than 110 % of the
maximum RATED supply voltage?
Some INTERNALLY POW ERED EQUIPMENT may be designated for use in areas with
specific maximum supply voltages less than 230 V.
WG 14 recommendation I NTERNALLY POW ERED EQUIPMENT provided with a means of connection to a supply
mains shall be tested at 110 % of the maximum RATED supply voltage.
I NTERNALLY POW ERED EQUIPMENT designated for use in areas with specific maximum
supply voltages, e.g. North America, should also be tested at 110 % of the maximum
supply voltage. If in doubt, 230 V should be taken as the maximum supply voltage.
– 20 – TR 62296 © IEC:2009(E)
2.2.10 Creepage distances and air clearances: Values under 1 mm
Requirement, clause no. 57.10. C REEPAGE DISTANCES and AIR CLEARANCES
Test clause no. 57.10 d.
Source/Problem For values of AIR CLEARANCE under 1 mm in Table XVI it is difficult to apply rules to
evaluate clearance and creepage according to Figures 39 to 47 since creepage =
clearance.
Discussion/comment Either Table XVI is wrong or the rules of measurement are wrong.
The requirement is in line with IEC 60664-1 for pollution degree 2. It seems in
IEC 60601-1 the assumption was made that EQUIPMENT would only be used in an
environment equal to pollution degree 2 of IEC 60664-1.
WG 14 recommendation A IR CLEARANCES less than 1 mm can not be used to meet the requirements for BASIC
INSULATION .
TR 62296 © IEC:2009(E) – 21 –
2.2.11 Separation: Secondary circuit impedance limit LEAKAGE CURRENT
Recommendation deleted: text implemented in recommendation No. 1
– 22 – TR 62296 © IEC:2009(E)
2.2.12 E NCLOSURES and PROTECTIVE COVERS : Lampholder/switching device
Problem raised in: SC 62A/WG 14(Germany)1
Requirement, clause no. 16d) ENCLOSURES and protective covers.

Parts within the ENCLOSURE of EQUIPMENT with a circuit voltage exceeding 25 V
a.c. or 60 V d.c. which cannot be disconnected from the supply by an external
mains switch or a plug device that is accessible at all times (for example, in
circuits for room lighting, remote control of the main switch etc.) shall be
protected against contact even after opening of the ENCLOSURE (for example, for
the purpose of maintenance) by additional coverings or, in the case of a spatially
separated arrangement, shall be marked clearly as “ LIVE ”
16e) E NCLOSURES protecting against contact with LIVE parts shall be removable
only with the aid of a TOOL or, alternatively, an automatic device shall make these
parts not LIVE , when the ENCLOSURE is opened or removed.
Excluded are:
1)..............................................
2) Lampholders allowing access to LIVE parts after removal of the lamp.
Test clause no. Compliance is checked by inspection and:
– by measurement of the effectiveness of an automatic switching off or
discharging device;
– by measurement of the voltage of LIVE parts accessible with the standard
test finger of Figure 7.
Source/Problem a) What is the definition of a lampholder?

b) What are the requirements for the automatic switching off device?
Discussion/comment a) Since everybody is familiar with changing a "normal" lamp, and therefore
these were excluded, this exclusion should only apply to standard lampholders,
i.e. Edison screw and bayonet cap.
b) The automatic switching off device fulfils the function of an isolating means
and should have the same requirements as a mains switch.
WG 14 recommendation a) The exclusion for lampholders shall apply only to standard lampholders e.g.,
Edison screw and bayonet cap.
b) The automatic switching off device shall comply with the requirements for
isolation given in 57.1 a) and d).
The automatic switching off device shall not be capable of manual resetting by
the OPERATOR . Compliance should be checked by inspection and with the
standard test finger of Figure 7.
TR 62296 © IEC:2009(E) – 23 –
2.2.13 Fixing, prevention of maladjustment: Torque test
Problem raised in: SC 62A/WG 14(Australia)1
Requirement, clause no. 56.10b) Fixing, prevention of maladjustment.

2nd dash: Controls........shall be so secured that the indication of any scale
always corresponds with the position of the control.
Test clause no. Compliance is checked by inspection and manual tests. For rotating controls, the
torques as shown in Table XIII shall be applied between the control knob and the
shaft for not less than 2 s in each direction alternately. The test shall be repeated
10 times.
Source/Problem a) The criteria is that the knob shall not rotate with respect to the shaft. This
does not cover the possibility of internal damage to the controlling device e.g.
potentiometer.
b) The torque test values are too high. Maximum torque on a 10 mm diameter
knob was found to be < 0,5 Nm.
Discussion/comment The adequacy of the knob/shaft mechanical link is covered by 56.10b). The
adequacy of the mechanical stops, wherever located, is covered by 56.10b). This
is intended to minimise the potential for internal damage by excessive torque.
WG 14 recommendation WG 14 does not feel that the torque test values in Table XIII are excessive.
– 24 – TR 62296 © IEC:2009(E)
2.2.14 Batteries not intended to be changed by OPERATOR : Lithium batteries
Problem raised in: SC 62A/WG 14(Israel)1
Requirement, clause no. 6.2d) The type of battery and the mode of insertion, if applicable, shall be marked
(see item b) of 56.7).
For batteries not intended to be changed by the OPERATOR and which can be
changed only with the use of a TOOL , an identifying marking referring to
information stated in the ACCOMPANYING DOCUMENTS is sufficient.
Test clause no. Compliance with the requirements of 6.2 is checked by application of the tests
and criteria as described in 6.1, except for the rubbing test.
Source/Problem Lithium batteries are commonly used for memory backup. There is a risk of
explosion if such batteries are soldered in position by an inadequately trained
person.
Discussion/comment Requirements for associated circuits to the lithium battery are included in
subclause 13.2.2 of IEC 61010-1:2001.
WG 14 recommendation Although 6.8.3 addresses it in general, it is recommended that particular

attention be drawn to this in the technical description.
TR 62296 © IEC:2009(E) – 25 –
2.2.15 Excessive temperatures: Ambient temperatures
Problem raised in: SC 62A/WG 14(Israel)1
Requirement, clause no. 42.2 E QUIPMENT parts and their environment shall not attain temperatures
exceeding the values as given in Table Xb when the EQUIPMENT is operated
during NORMAL USE and under NORMAL CONDITIONS at an ambient temperature of
25 ºC.
Test clause no. Compliance with the requirements of 42.1 to 42.3 is checked by operation of
EQUIPMENT and temperature measurement as follows:
Source/Problem The manufacturer could specify higher ambient temperatures than 25 ºC. Should
this influence the test conditions?
Discussion/comment The tests for 42.2 are carried out at the prevailing ambient temperature, and the
test results corrected to determine the temperature which would have been
reached had the ambient temperature been 25 ºC.
WG 14 recommendation Table Xa gives the permissible temperature of materials for an ambient

temperature of 40 ºC. Table Xb gives the permissible temperature of materials for
an ambient temperature of 25 ºC.
Tests will be conducted at ambient temperatures in the range 10 ºC to 40 ºC. The
measured temperature obtained shall be corrected for an ambient temperature of
either 40 ºC (Xa) or 25 ºC (Xb). These corrected temperatures are used for
comparison with the allowed maximum values for materials in Tables Xa and Xb.
The table below gives examples of tests carried out at 35 ºC and the results of
corrections.
Parts Ambient º C Measure value Corrected value for Corrected value at Allowable values
at ambient 25 º C ambient 40 º C ambient listed in
listed in Xa 35 130 — 135 Table Xa
listed in Xb 35 110 100 — Table Xb

– 26 – TR 62296 © IEC:2009(E)
2.2.16 Continuous LEAKAGE CURRENTS : Different SUPPLY MAINS
Problem raised in: SC 62A/WG 12 (Israel)1
Requirement, clause no. 19.1 Continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS .
Test clause no. 19.1 e),f) and g), 19.2 a) and b)
Source/Problem Where an EQUIPMENT is capable of operating from different SUPPLY MAINS , e.g.
a.c. mains supply or d.c. mains supply, do the tests need to be repeated for each
supply?
Discussion/comment An EQUIPMENT is defined in 2.2.15 as having only one connection to a particular

SUPPLY MAINS . This means that connection should only be possible to one SUPPLY
MAINS at any one time. However there may be situations where leakage currents
could be worse with a particular modality of SUPPLY MAINS even though of lower
voltage, e.g. with d.c. supply. The 2nd edition of IEC 60601-1 does not
specifically address this.
WG 14 recommendation If examination of the circuit arrangements suggests that there might be a

problem, tests should be repeated for other SUPPLY MAINS modalities.
TR 62296 © IEC:2009(E) – 27 –
2.2.17 E NCLOSURE and protective covers: E QUIPMENT in ambulances
Problem raised in: BSI document 94/501410
Requirement, clause no. 16 E NCLOSURES and protective covers.

E QUIPMENT shall be so constructed and enclosed that there is adequate
protection against contact with LIVE parts.................
20.1 A-a 1 Dielectric strength between LIVE parts and accessible metal parts.
19.2 S INGLE FAULT CONDITIONS .
Test clause no. 16, 20, 19.2
Source/Problem Some EQUIPMENT , designed for use in ambulances and operated from the vehicle
d.c. supply, connects the negative side of the supply to the enclosure. Is this
acceptable?
Discussion/comment It could be argued that since a vehicle d.c. supply's negative pole is commonly
connected to the vehicle chassis, this pole cannot become LIVE . However the
possibility remains of the MAINS PLUG or MAINS CONNECTOR being incorrectly wired
or connected, which would cause the EQUIPMENT ENCLOSURE to assume the full
voltage of the SUPPLY MAINS .
There is also the possibility of interruption of the negative pole of the supply,
which would result in excessive ENCLOSURE LEAKAGE CURRENT . Although this
could be prevented by a PROTECTIVE EARTH CONDUCTOR , which would then have
to carry the continuous full load current, the WG does not think that this would be
desirable.
WG 14 recommendation Connection of the negative side of the d.c. mains to the ENCLOSURE should not be
permitted. The insulation between all poles of the supply and the ENCLOSURE
shall comply with BASIC INSULATION (for parts of opposite polarity) and DOUBLE
INSULATION (between the supply and the ENCLOSURE ).
– 28 – TR 62296 © IEC:2009(E)
2.2.18 Dielectric strength: Voltages appearing from external sources
Problem raised in: BSI interpretation 64-68/158-159
Requirement, clause no. Clause 20 Dielectric strength

20.1. General requirements for all types of EQUIPMENT .
A-k
This insulation need not be investigated separately if at least one of the following
conditions is satisfied:
a) The voltages appearing on the SIGNAL INPUT PART or SIGNAL OUTPUT PART in
NORMAL USE do not exceed SAFETY EXTRA - LOW VOLTAGE .
b) The LEAKAGE CURRENTS do not exceed the allowable values in SINGLE FAULT
CONDITION in the event of any single component failure in the SIGNAL INPUT PART
or SIGNAL OUTPUT PART .
d) The SIGNAL INPUT PARTS or SIGNAL OUTPUT PARTS are designated by the
manufacturer for connection to EQUIPMENT in situations where no risk of external
voltage exists (see IEC 60601-1-1).
Test clause no. 20.1
Source/Problem I) Does exemption a) refer to voltages arising within the EQUIPMENT , to voltages
appearing from external sources, or both?
ii) Does exemption b) refer to the SINGLE FAULT CONDITION of MAINS VOLTAGE on
the SIP or SOP? Is insulation which ensures absence of excessive LEAKAGE
CURRENTS not to be tested?
iii) For exemption d) to apply, does the manufacturer have to restrict connection
of the SIP and SOP to other MEDICAL ELECTRICAL EQUIPMENT or can connection to
non-medical equipment be permitted, subject to some restrictions?
Discussion/comment a) is intended to cover the W ORKING VOLTAGES on the SIP or SOP in NORMAL USE
regardless of their origin.
b) is intended to cover the SINGLE FAULT CONDITION caused by a component
failure within the SIP or SOP in NORMAL USE .
d) exemption does not allow connection to equipment, only EQUIPMENT , as
defined, is covered.
WG 14 recommendation i) a) applies only if the voltages within the SIP and SOP are less than SAFETY
EXTRA - LOW VOLTAGE when connected to EQUIPMENT consistent with the
instructions for use.
ii) b) applies to a SINGLE FAULT CONDITION resulting from a single component
failure within the SIP or SOP in NORMAL USE , i.e. connected as specified in the
instructions for use. If such a SINGLE FAULT CONDITION does not produce
excessive LEAKAGE CURRENTS then no additional insulation test is needed.
iii) d) according to IEC 60601-1-1, this applies only if the manufacturer restricts
connection of MEDICAL ELECTRICAL EQUIPMENT or non- MEDICAL ELECTRICAL
EQUIPMENT which comply with relevant IEC and ISO safety standards to the
SIP/SOPs.
See also Recommendation 58.
TR 62296 © IEC:2009(E) – 29 –
2.2.19 Testing switch mode power supply units (SMPSU)
Problem raised in: 62A/WG14 (Piestany/Hagiwara)1
Requirement, clause no. Testing SMPSUs
Test clause no. 7.1, 15b, 19, 20, 42, 52.5.1, 52.5.9, 57
Source/Problem SMPSU are not addressed in IEC 60601-1:1988 (see Appendix A, 57.9).
Reference voltage in SMPSU can be measured in different manners.
Specificity of SMPSU leads to difficulties when applying requirements of
IEC 60601-1:1998.
Discussion/ comment The following items have to be taken into account :

7.1 power input;
15.b limitation of voltage and/or energy;
19 continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS , (For
the time being, SMPSUs which use frequency higher than 1 MHz should
not be used for EQUIPMENT which has a direct conductive connection to
the heart);
20 dielectric strength;
42 excessive temperatures;
52.5.1 overloading of mains supply transformers;
52.5.9 failure of components;
57.10 CREEPAGE DISTANCES and AIR CLEARANCES .
WG 14 recommendation 7.1 According to 6.1.j (power factor is often lower than 0.9).
15.b Item described but read only capacitor instead of interference
suppression capacitor in "The test between lines shall not be performed
if interference suppression capacitor....".
19 No recommendation – shall be addressed by relevant WG for next
edition.
20 Between components and between inputs and outputs of SMPSU.
Reference voltage: mains voltage (even if testing value is more severe
for components such as optical isolators) or
SMPSU being in normal use, by measurement of reference voltage
(RMS) between components: transformers, optical isolators,... (in using
a 2 channels differential oscilloscope : Ref. O V and neutral grounded to
earth);
42 Tested together with the equipment (depends on the load, fans, location,
etc.…).
52.5.1 Test according to 57.9.1.b) fourth dash, fifth bullet. The power supply is
loaded on the output. If the SMPSU is protected against overload by an
electronic device, the device is bridged during the test. The electronic
device does not need to be bridged if every defect in the SMPSU can be
discovered or leads to an inoperability.
52.5.9 Tests like described. If not already covered by a component failure, a
short circuit shall be applied directly across the transformer secondary
windings (short circuiting across the transformer secondary windings
ensures there are no safety hazards in the event of short circuit in the
windings of the transformer, taking into account that there are no
dielectric strength tests 5 times the voltage: 57.9.2).
57.10 By using reference voltage measured or evaluated at Clause 20.
– 30 – TR 62296 © IEC:2009(E)
2.2.20 Failure of an electrical component: Time periodicity for detection
Problem raised in: 62A/WG14 (Milan)5
Requirement, clause no. Condition in which a single means for protection against a SAFETY HAZARD in
EQUIPMENT is defective or a single external abnormal condition is present.
Failure of an electrical component which might cause a SAFETY HAZARD
Test clause no. 2.10.11, 3.6 f)

Refer also to 4.1.
Source/Problem Shall a fault which remains undetected be considered as NORMAL CONDITION (NC)
or SINGLE FAULT CONDITION (SFC)?
If every fault is considered as SFC, regardless of whether it is detected or not,
the consequence will be that there is no protection required against situations
where an undetected first fault is followed by a second fault which may cause a
SAFETY HAZARD .
Discussion/ comment See Annex A, rationale for subclause 3.6 item d) – a single fault is discovered
and remedied by periodic inspection and maintenance which is prescribed in the
instructions for use.
Also autotest, when switching on can check the protective device.
A faulty condition becomes a SFC when detected.
Reaction time after a SFC (when detected) should be also taken into account.
WG 14 recommendation If a fault is not detected (for example by periodic inspection, maintenance,
autotest, etc ....), it shall not be considered as a SINGLE FAULT CONDITION .
Time periodicity for the detection of fault depends on risks analysis.
Refer also to 4.1.
TR 62296 © IEC:2009(E) – 31 –
2.2.21 Environmental conditions: Compliance paragraph
Requirement, clause no. Environmental conditions
Test clause no. 10.1, 10.2
Source/Problem Compliance with the conditions of 10.2 is checked by application of the tests of
this standard.
10.1 is no longer included in IEC 60601-1:1988: in Amendment 2 replaced by
"E QUIPMENT shall be capable, while...environmental conditions as stated by the
manufacturer (see 6.8.3.d)".
Discussion/ comment Instead of "E QUIPMENT shall be capable ...", we should read something like : After
packaging, transport and storage, the EQUIPMENT shall be in compliance with the
standard.
Subclause 10.1 does not contain any compliance paragraph, therefore we
recommend that a compliance paragraph should be added and further work is
needed.
WG 14 recommendation E QUIPMENT shall comply with the requirements of this standard after being
exposed to the environmental conditions as stated by the manufacturer.
Compliance may be checked by testing and/or inspection of documentary
evidence.
– 32 – TR 62296 © IEC:2009(E)
2.2.22 Limitation of voltage and/or energy: Capacitance
Requirement, clause no. "The tests between lines and ENCLOSURE shall not be performed if interference
suppression capacitors are used...."
"The tests between lines shall not be performed if interference suppression
capacitors are used...."
Test clause no. 15 b)
Source/Problem In most EQUIPMENT , interference suppression capacitors are not the only
capacitance used.
Discussion/ comment Replace "interference suppression capacitor" by "the measured capacitance".
WG 14 recommendation To measure the capacitance between lines and ENCLOSURE and between lines.
TR 62296 © IEC:2009(E) – 33 –
2.2.23 L EAKAGE CURRENTS : Presence of 45 kΩ resistor in Figure 21
Requirement, clause no. In Figure 21, presence of a resistance of 45 kΩ resistor
Test clause no. 19
Source/Problem Because of the 45 KΩ resistor, the current is always limited to 5 mA, and the limit
is 5 mA.
Discussion/ comment
WG 14 recommendation For first edition, use the method of 2nd edition (use any resistance).
For 2nd edition, instead of using a resistor in series, a fuse could be used or
gradually ramping the applied voltage to required test value.
– 34 – TR 62296 © IEC:2009(E)
2.2.24 Humidity preconditioning treatment: Exception from requirement
Problem raised in: 62A(Sec)140A (USA)
Requirement, clause no. 4.10 Humidity preconditioning treatment
Test clause no. 4.10 (is a test clause)
Source/Problem Should this test be applied to EQUIPMENT which is permanently installed and
operated only in a controlled temperature and humidity conditions as specified in
the ACCOMPANYING DOCUMENTS ?
Discussion/comment Certain EQUIPMENT is permanently installed and operated in controlled

temperature and humidity conditions. Nevertheless IEC 60601-1:1988 requires
equipment to comply with all the relevant parts of the standard when exposed to
the environmental conditions specified in 10.2.1, even though the operating
conditions may be restricted, as allowed in 6.8.3.
WG 14 recommendation Requirements of 4.10 apply to all EQUIPMENT even when specified for use in a
controlled environment However, attention is drawn to the exception noted in the
3rd paragraph of 4.10:
The test shall be applied only to those EQUIPMENT parts likely to create a SAFETY
HAZARD when influenced by the climatic conditions that are simulated by the test.
TR 62296 © IEC:2009(E) – 35 –
2.2.25 Dielectric strength: E QUIPMENT containing floating circuits
Problem raised in: SC/62A(Sydney)8
Requirement, clause no. 20 Dielectric strength

20.2 Requirements for EQUIPMENT with an APPLIED PART . (B-e requirement).
Source/Problem An EQUIPMENT may contain floating circuits which under the definition 2.1.10
would not be considered as LIVE , since contact with these parts could not result
in excessive leakage currents to earth or to other ACCESSIBLE PARTS . There would
therefore appear to be no requirements for safety separation between these
circuits and ACCESSIBLE PART or APPLIED PARTS . But voltages within these circuits
or in conjunction with other circuits may lead to currents exceeding the values
given in Table IV.
Discussion/comment There are two possibilities for solving this problem. One is to change the
definition of LIVE and adopt the requirements for insulation accordingly. The
second is to treat the separation of the isolated circuits as subject to failure.
If one pole of the isolated circuit is short circuited to earth (failure of insulation),
then the other pole becomes LIVE and the adequacy of the separation of this LIVE
part under these conditions may be assessed. If that separation is inadequate,
then it should be short circuited in turn to assess the separation on the other
pole.
Since for an isolated circuit there may be two separate protective insulations (on
either pole), WG14 proposes that each of these can be BASIC INSULATION rather
than BASIC and SUPPLEMENTARY INSULATION . Of course other combinations may
be used, although if the insulation of one pole is less than BASIC INSULATION then
the other pole must have DOUBLE INSULATION or REINFORCED INSULATION .
WG 14 recommendation If the failure of insulation of such isolated circuits is likely to lead to a SAFETY
HAZARD , such insulation should be short circuited before determining whether a
part is LIVE . This short circuit should not be treated as a SINGLE FAULT CONDITION
unless the insulation concerned satisfies the requirements for BASIC or
SUPPLEMENTARY INSULATION necessary for the voltages within the isolated part.
– 36 – TR 62296 © IEC:2009(E)
2.2.26 General requirements for tests: Measurement uncertainty
Problem raised in: Australian draft document Supplement 1 to AS 3200-1

(technically equivalent to IEC 60601-1:1988)
Requirement, clause no. All requiring measurements
Test clause no. All requiring measurements
Source/Problem The Australian document proposes that measurement uncertainty should be
stated in the standard for many physical and electrical parameters.
Discussion/comment The WG decided that measurement uncertainty should not generally be part of
any revision to the standard.
WG 14 recommendation Test laboratories should deal with measurement uncertainty in line with
ISO/IEC 17025 and guidance in IECEE-CTL Guide 001.
TR 62296 © IEC:2009(E) – 37 –
2.2.27 C REEPAGE DISTANCES and AIR CLEARANCES : Interpolated values

20.3 Values of test voltages
57.10 C REEPAGE DISTANCE and AIR CLEARANCES
Test clause no. 20.

57.10 d)
Source/Problem The reference voltage (U) as used in Table V is the voltage to which the relevant
insulation is subjected in NORMAL USE and at RATED supply voltage or a voltage
specified by the manufacturer, whichever is the greater.
The value of the reference voltage (U) is as given in 20.3. In case the reference
voltage has a value between those given in Table XVI, the higher of the two
values shall be applied.
Discussion/comment Assume the following case. An EQUIPMENT with functionally earthed secondary
circuits or a floating accessible secondary SIGNAL INPUT PART or SIGNAL OUTPUT
PART . Mains (primary) voltage 230 V and a nominal secondary voltage of 24 V, a
very common application. Theoretically the voltage the insulation is subjected to
will be the sum of the two voltages above. Hence it follows that the reference
voltage will 254 V. The relevant dielectric strength test for A-e, see 20.1, will then
be 4 016 V for DOUBLE INSULATION or REINFORCED INSULATION . The corresponding
requirement for CREEPAGE DISTANCE and AIR CLEARANCES will, on the other hand
be 12 mm and 7 mm respectively. Is it the intention of the standard that 20.3 and
57.10 not be aligned (continuity in Table V but discontinuity in Table XVI for
reference voltages above 250 V) or is this a misinterpretation?
WG 14 recommendation To avoid application of sudden increases in CREEPAGE DISTANCE and AIR
CLEARANCE it is recommended that interpolated values between reference
voltages in Table XVI be used to determine these values. The AIR CLEARANCE can
only be interpolated if the reference voltage is 2 800 V or more.
– 38 – TR 62296 © IEC:2009(E)
2.2.28 Overheating: Change of load resistance
Requirement, clause no. 57.9 Mains supply transformers.

57.9.1 b) Overload
Mains supply transformers including their protective devices, if any, are tested in
conditions of normal operation: .... – the section or winding of the transformer
under overload is loaded as follows:
• Mains supply transformers having fuses in accordance with IEC 60127-1 and
IEC 60241 as protective devices, are loaded for 30 min and 1 h respectively,
so that the test current in the fused circuit is in accordance with Table XX
with the fuses replaced by links of negligible impedance.
Test clause no. 57.9.1 b)
Source/Problem Swedish comment: Practically the test is performed with the winding under
overload connected to a resistor with the resistance value that yields the correct
test current in accordance with Table XX. As the windings get heated during the
test, their resistance increases and one has to decrease the value of the load
resistor to keep the current in the fused circuit in accordance with Table XX
during the test. Since the decrease of current is a result of the increase in the
winding’s temperature, it seems to be an unrealistic fault condition to keep the
current in the fused circuit unchanged instead of keeping the load resistance
unchanged.
Discussion/comment Canadian comment: Although the winding resistance increases requiring a
decrease in the load resistance to maintain the test current, this would present a
worst case test. The overload test is based on the protective device
characteristics. The test current must remain constant because it is not known
what will happen in the abnormal conditions. The only known factor is the criteria
for the protective device.
WG 14 recommendation Endorse the Canadian comment. The test load current must be maintained at its
original value.
TR 62296 © IEC:2009(E) – 39 –
2.2.29 Mains operated EQUIPMENT with additional power source: Integrity of external
protective earth
Requirement, clause no. 6.8.2 Instructions for use

6.8.2 e) Mains operated EQUIPMENT with additional power source.
If CLASS I EQUIPMENT is specified for operation connected to a SUPPLY MAINS and
alternatively using an INTERNAL ELECTRICAL POW ER SOURCE , instructions for use
shall contain a statement saying that where the integrity of the external
PROTECTIVE EARTH CONDUCTOR arrangement is in doubt, EQUIPMENT shall be
operated from its INTERNAL ELECTRICAL POW ER SOURCE .
Test clause no. 6.8
Source/Problem Swedish comment: The requirement seems to be a little unreasonable. Assume
for example, an EQUIPMENT with an internal battery intended for back-up power in
the event of a failure of the SUPPLY MAINS as a power source. Further, how can
one say whether the external PROTECTIVE EARTH CONDUCTOR arrangement is in
doubt or not?
Discussion/comment This appears to be directed at EQUIPMENT used in the home, where the integrity
of the protective earth may be less certain. The WG would be happy to see this
subclause removed altogether. The recommendation is intended to draw an
unskilled user’s attention to the importance of protective earthing.
WG 14 recommendation The Instructions for use shall include for CLASS I EQUIPMENT the following
statement:
“WARNING: THIS EQUIPMENT MUST ONLY BE CONNECTED TO A SUPPLY
MAINS WITH PROTECTIVE EARTH.”
– 40 – TR 62296 © IEC:2009(E)
2.2.30 Rechargeable batteries: No OPERATOR / USER maintenance
Requirement, clause no. 6.8.2 Instructions for use

6.8.2 g) Rechargeable batteries
Instructions for use of EQUIPMENT containing rechargeable batteries shall contain
instructions to ensure safe use and adequate maintenance.
Test clause no. 6.8
Source/Problem Swedish comment: The standard does not make any exceptions for rechargeable
batteries permanently mounted in EQUIPMENT not intended to be maintained by
the operator. For example batteries that supply audible alarms. The requirement
should only be applicable for batteries that are exclusively intended to be
maintained by the OPERATOR and/or where risk of overcharging is present.
Discussion/comment WG fully agrees with the Swedish comment.
WG 14 recommendation Where batteries are completely free of OPERATOR / USER maintenance, the
instructions for use shall contain a statement to that effect.
TR 62296 © IEC:2009(E) – 41 –
2.2.31 Isolation from the SUPPLY MAINS : Symbol for single pole switch
Requirement, clause no. 57.1 Isolation from the SUPPLY MAINS

57.1 a) Isolation
– E QUIPMENT shall have means to isolate its circuits electrically from the
SUPPLY MAINS on all poles simultaneously. This isolation shall include each
LIVE supply conductor, except that PERMANENTLY INSTALLED EQUIPMENT
connected to a polyphase SUPPLY MAINS may be provided with a device
which does not interrupt the neutral conductor, but only if local installation
conditions are such that in NORMAL CONDITION the voltage on the neutral
conductor can be expected not to exceed extra-low voltage.
– Means for isolation shall either be incorporated in EQUIPMENT or, if external,
shall be specified in the ACCOMPANYING DOCUMENTS (see 6.8.3)
57.1 h)
In non- PERMANENTLY INSTALLED EQUIPMENT a suitable plug device used to isolate
EQUIPMENT from the SUPPLY MAINS shall be considered as complying with the
requirements of 57.1 a).
APPLIANCE COUPLERS and flexible cords with MAINS PLUGS are suitable plug
devices.
Source/Problem Swedish comment: Is single phase non- PERMANENTLY INSTALLED EQUIPMENT W ith a
suitable plug device according to item h) of 57.1 allowed to incorporate a switch
that isolates its circuits electrically from only one SUPPLY MAINS pole? How shall
the different positions of the switch be indicated?
Discussion/comment Yes, the standard clearly permits such a switch. The use of symbols 15 and 16 is
however prohibited for such functional switches.
WG 14 recommendation Symbols used on functional switches shall not use symbols 15 and 16. Any
symbol used must be reproduced and fully explained in the Instructions for use.
Suitable symbols from IEC 60417 could be 5009, 5264 and 5265.
– 42 – TR 62296 © IEC:2009(E)
2.2.32 Sequence of testing: Clause 52 before Clause 19
Requirement, clause no. Appendix C. Sequence of testing

C.1 General: Tests should, if applicable, be carried out in the sequence indicated
below, unless otherwise stated by particular standards. The sequence of the tests
marked by an * is mandatory. See also 4.11. However, this does not preclude the
possibility of conducting a test which preliminary inspection suggests might cause
failure.
19 Continuous LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS .
Test clause no. 19.4 Tests
19.4 a) General 1) The EARTH LEAKAGE CURRENT , the ENCLOSURE LEAKAGE
CURRENT , the PATIENT LEAKAGE CURRENT and the PATIENT AUXILIARY CURRENT are
measured:
– after the EQUIPMENT has been brought to operating temperature in accordance
with the requirements of Section Seven.
Source/Problem Swedish comment: The standard states that a test under abnormal operations
and fault conditions, Clause 52, shall be performed before the measurements of
LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS at operating temperature,
even if the tests might cause failure. If those tests cause failures that make the
EQUIPMENT unable to operate in NORMAL USE and NORMAL CONDITION , the
measurement of LEAKAGE CURRENTS and PATIENT AUXILIARY CURRENTS at
operating temperatures will be impossible.
Discussion/comment WG agrees with the Swedish comment.
WG 14 recommendation In Appendix C ignore all asterisks (*) and the second sentence in C1, “The
sequence of tests marked by an * is mandatory”.
TR 62296 © IEC:2009(E) – 43 –
2.2.33 S INGLE FAULT CONDITION : E NCLOSURE LEAKAGE CURRENT from INTERNALLY POWERED
EQUIPMENT
Requirement, clause no. 19. S INGLE FAULT CONDITIONS

19.2 c) Additionally the ENCLOSURE LEAKAGE CURRENT shall be measured with a
voltage equal to 110 % of the highest RATED MAINS VOLTAGE applied between
earth and any SIGNAL INPUT PART or SIGNAL OUTPUT PART .
Test clause no. 19.4 g) Measurement of the ENCLOSURE LEAKAGE CURRENT
3) E QUIPMENT specified for connection to an SELV-source and INTERNALLY
POW ERED EQUIPMENT is tested for ENCLOSURE LEAKAGE CURRENT flowing between
different parts of the ENCLOSURE (measuring device applied as MD2 in Figure 18).
Figure 18: Measuring circuit for ENCLOSURE LEAKAGE CURRENT .
Source/Problem Swedish comment: Since INTERNALLY POW ERED EQUIPMENT has no reference to
earth, the ENCLOSURE LEAKAGE CURRENT flowing between different parts of the
ENCLOSURE will not be affected by an external voltage applied between earth and
a SIGNAL INPUT PART or SIGNAL OUTPUT PART . Therefore, the ENCLOSURE LEAKAGE
CURRENT for INTERNALLY POW ERED EQUIPMENT caused by such a voltage, should
be measured as for CLASS II EQUIPMENT with MD1 between the ENCLOSURE and
earth according to Figure 18. Further, the external voltage to be applied should
be specified in item g) 3) of 19.4, in a similar way as in item h) 8) of 19.4 and
Figure 25 (Measurement of the PATIENT LEAKAGE CURRENT flowing from the
APPLIED PART to earth, caused by an external voltage between earth and any
SIGNAL INPUT PART or SIGNAL OUTPUT PART ), except that supply frequency does not
apply for EQUIPMENT with an internal battery.
Discussion/comment WG agrees with Swedish comment.
WG 14 recommendation Modify item g) 3) of 19.4 to read: .......”and INTERNALLY POWERED EQUIPMENT is

tested for ENCLOSURE LEAKAGE CURRENT flowing between the ENCLOSURE and
earth and also between different parts of the ENCLOSURE (measuring device
applied as MD1 and MD2 in Figure 18).”
– 44 – TR 62296 © IEC:2009(E)
2.2.34 Marking on the outside of EQUIPMENT: Type and rating of fuses
Requirement, clause no. 6.1. Marking on the outside of EQUIPMENT or EQUIPMENT parts
6.1 n). Fuses. The type and rating of fuses accessible from the outside of
EQUIPMENT shall be marked adjacent to the fuse-holder.
Test clause no. 6.1
Source/Problem Swedish comment: Shall fuse-holders intended for fuses in accordance with
EN 60127 (IEC 60127) be provided with adjacent complete marking according to
the requirements in these standards or can, for example, the rated voltage be
omitted? See Clause 6, Marking, of IEC 60127-1:1988 and IEC 60127-2:1989.
Discussion/comment This requirement is interpreted as meaning that the marked ‘rating’ should
include the rated current, voltage, fuse characteristic and high (H) or low (L)
breaking capacity designation in accordance with the relevant fuse standard.
WG 14 recommendation The marking shall be in accordance with the applicable fuse standard.
TR 62296 © IEC:2009(E) – 45 –
2.2.35 Excessive temperatures: APPLIED PARTS not intended to supply heat
Problem raised in: National comments
Requirement, clause no. 42 Excessive temperatures.

42.3. A PPLIED PARTS of EQUIPMENT not intended to supply heat to a patient shall
not have surface temperatures exceeding 41 °C.
Test clause no. 42
Source/Problem UK comment: It is not clear at what ambient temperature the limit of 41 °C should
be applied. The temperature range of 10 °C to 40 °C stated in 10.2 applies to
Table Xa and would appear to apply in this instance. Is a 1 °C temperature
difference correct or realistic?
Discussion/comment It may be possible to consider a reduced maximum ambient temperature, say

35°C, if that is stated by the manufacturer in the instructions for use.
WG 14 recommendation When no ambient temperature is specified by the manufacturer, a maximum of

40 °C ambient shall be used. The limit of 41 °C on APPLIED PARTS of EQUIPMENT
not intended to supply heat to a PATIENT must be applied in NORMAL CONDITION
and SINGLE FAULT CONDITION . An exception would be where there is a medical
justification for a higher limit/temperature rise. This requirement should also be
addressed in particular standards.
– 46 – TR 62296 © IEC:2009(E)
2.2.36 Mains supply transformers: Use of PTCs as protective devices
Problem raised in: SC 62A/WG 14 (Milan) 8
Requirement, clause no. 57.9 b) Mains supply transformers. Overload
Test clause no.
Source/Problem Is it permitted to use a PTC as a protective device and what should be the
overload test?
Discussion/comment WG14 does not see any reason why a PTC may not be used. Consideration
should be given to Clause 49.1. However there is concern about the reliability of
such devices.
WG 14 recommendation Where a PTC is used as a protective device for a mains supply transformer, the
requirements for THERMAL CUT - OUTS as required by 57.9 shall be applied.
A positive temperature coefficient resistive device (PTC) is to be left in the circuit
for the short circuit test until ultimate results. For the overload test the maximum
loading not resulting in the PTC switching to its high resistance mode is to be
used until ultimate results are known.
They shall be in accordance with international or national standards which
address the reliability of these components, e.g. as specified in 2.5 of IEC 60950-
1:20051.
TR 62296 © IEC:2009(E) – 47 –
2.2.37 Components and general assembly: Reliability of components
Problem raised in: SC 62A/WG 14
Requirement, clause no. 56 Components and general assembly
Test clause no.
Source/Problem 56.1 b) requires that ratings of components shall not conflict with the conditions
of use in EQUIPMENT . There are no requirements for components themselves to
meet specific standards which include the control of reliability.
Discussion/comment WG14 is concerned that components, particularly in the MAINS PART and in
APPLIED PARTS , are not required to have any proof of their suitability.
WG 14 recommendation WG 14 strongly recommends that components in the MAINS PART and in APPLIED
PARTS should comply with recognised component standards, consistent with their
use. WG 14 suggests the following hierarchy of acceptable standards:
International standards (e.g. IEC, ISO etc.)
National standards (e.g. BSI, DIN, UL etc.)
Component manufacturer standards, covered by suitable quality control
procedures.
The manufacturer’s tests and controls, supported by appropriate technical
documentation.
As a minimum, components have to comply with IEC 60601-1 requirements.
– 48 – TR 62296 © IEC:2009(E)
2.2.38 Definition of APPLIED PART: E QUIPMENT worn by PATIENTS
Problem raised in: WG14/London/1 62A/WG14 (Canada)11
Requirement, clause no. 2.1. A PPLIED PART (second dash)

– can be brought into contact with the PATIENT ; or
Test clause no. 2.1.5, 42
Source/Problem E QUIPMENT worn by the patient, such as an ambulatory ECG system or an
ambulatory recorder, is now considered as an APPLIED PART in addition to the
associated electrodes and cables. Subclause 42.3 does not allow surface
temperature exceeding 41 °C for an APPLIED PART and, according to 3.1,
EQUIPMENT , shall cause no safety hazard in NORMAL CONDITION and in SINGLE
FAULT CONDITION . Very often the EQUIPMENT exceeds the temperature limit of
41 °C under the above testing conditions.
Discussion/ comment Since the special temperature limits have been set for PATIENT contact, would the
patient clothing (if the manufacturer specifies that the EQUIPMENT should not be
worn directly on the body) change the classification?
WG 14 recommendation The instructions for use shall advise that the recorder is not to be worn in contact
with the skin (e.g. by using a pouch). The ENCLOSURE is therefore not considered
as an APPLIED PART and temperature measurements should be done on the
external surface of the carrying case. Temperature limits are the same as for an
APPLIED PART .
TR 62296 © IEC:2009(E) – 49 –
2.2.39 Construction: Triple insulated winding wire
Problem raised in: WG14/London/1, 62A/WG14 (Canada)12
Requirement, clause no. 57.9 Mains supply transformers

57.9.4 Construction
Test clause no. Compliance with the requirements is checked by inspection
Source/Problem Many manufacturers are using a triple insulated winding wire on a transformer,
where BASIC , DOUBLE , or REINFORCED INSULATION is required between the primary
and the secondary windings
Discussion/ comment Subclause 2.10.5.12 of IEC 60950-1:2005 requires such winding wire meet the
requirements of its Annex U. Can we follow a similar practice for equipment
evaluated to IEC 60601-1:1988?
WG 14 recommendation Requirements of Annex U of IEC 60950-1:2005 can be applied, but precautions

should be taken concerning possible mechanical damages to the wires. All other
requirements of 57.9 shall be applied.
– 50 – TR 62296 © IEC:2009(E)
2.2.40 C REEPAGE DISTANCES and AIR CLEARANCES : Dielectric strength test versus
CREEPAGE DISTANCES and AIR CLEARANCES
Problem raised in: WG14/London/1; 62A/WG14 (Canada)13
Requirement, clause no. 57.10 C REEPAGE DISTANCES and AIR CLEARANCES
Test clause no. Compliance with item d) of 57.10 is checked by inspection and measurement.
Source/Problem In many instances, it is not possible to comply with CREEPAGE DISTANCES and AIR
CLEARANCES without major redesign of the EQUIPMENT .
Discussion/ comment Would it be acceptable, in cases where the dielectric strength test is satisfactory,
to accept reduced CREEPAGE DISTANCES on PCB, provided satisfactory conformal
coating is applied and satisfactory thermal aging and thermal cycling tests are
performed as specified in IEC 60950-1?
WG 14 recommendation A necessary redesign is not a reason for reducing the CREEPAGE DISTANCES . The
values of CREEPAGE DISTANCES in Table XVI are very conservative. If conformal
coating withstands tests in IEC 60664-3, there are no CREEPAGE DISTANCES and
conformal coating can be treated as a solid insulating material.
TR 62296 © IEC:2009(E) – 51 –
2.2.41 C REEPAGE DISTANCES and AIR CLEARANCES : Dielectric strength test versus
CREEPAGE DISTANCES and AIR CLEARANCES – POWER SUPPLY CORDS
Problem raised in: SC 62A/WG 14 (Canada)14
Requirement, clause no. 57.4 Connection of POW ER SUPPLY CORDS
Test clause no. 57.4 a) Cord anchorages:
E QUIPMENT and MAINS CONNECTORS provided with POW ER SUPPLY CORDS shall
have cord-anchorages such that the conductors are relieved from strain,
including twisting, where they are connected within the EQUIPMENT and within the
MAINS CONNECTORS and the insulation of the conductors is protected from
abrasion.
57.4 b) Cord guards:
POW ER SUPPLY CORDS of other than STATIONARY EQUIPMENT shall be protected
against excessive bending at the inlet opening of EQUIPMENT by means of a cord
guard of insulating material.
Source/Problem In a mobile unit (with power supply cord attached), due to an excessive amount
of mobility of the EQUIPMENT , it is possible that it can damage internal parts of the
APPLIANCE COUPLER which eventually could result in fire.
Discussion/comment If the APPLIANCE COUPLER complies with IEC 60320-1, WG14 sees no possibility
of applying additional requirements. Up to now this was the first case which was
brought to the knowledge of WG14.
WG 14 recommendation If the APPLIANCE COUPLER is not according to IEC 60320-1, apply the tests
according to 57.4.
– 52 – TR 62296 © IEC:2009(E)
2.2.42 ACCOMPANYING DOCUMENTS : on CD-ROM or electronic file format
Problem raised in: WG14/London/2; 62A/WG14 (Canada)15
Requirement, clause no. 6.8 A CCOMPANYING DOCUMENTS
Test clause no. 6.8.1
Source/Problem 1) Is it a MUST that ACCOMPANYING DOCUMENTS shall be provided as hard copy?
2) What if ACCOMPANYING DOCUMENTS are provided either on CD-ROM or
electronic file format ?
Discussion/ comment
WG 14 recommendation 1) Agree that ACCOMPANYING DOCUMENTS may be in electronic format if

acceptable to the USER .
2) WG 14 draws attention to the fact that at least that part concerned with
safety shall be readable on a hard copy or as marking. A risk analysis will
indicate which information needs to be provided as hard copy or as markings
(e.g. emergency or critical care procedures).
TR 62296 © IEC:2009(E) – 53 –
2.2.43 I NTERNAL ELECTRICAL POWER SOURCE : Requirements for lithium batteries
Problem raised in: WG14/London/3; 62A/WG14(Norway)1/97
Requirement, clause no. 56.7 Batteries
Test clause no.
Source/Problem No specific requirements for lithium batteries.
Discussion/ comment IEC 60950-1 has requirements for lithium batteries.

6.2 d), 56.7 and 52.5.9 in IEC 60601-1:1988 already cover the requirements of
1.7.13 in IEC 60950-1:2005.
WG 14 recommendation The requirements of 6.2 d), 52.5.9 and 56.7 in IEC 60601-1:1988 have to be
applied to lithium batteries.
– 54 – TR 62296 © IEC:2009(E)
2.2.44 Dielectric strength: Differences between B-d and B-e
Requirement, clause no. 20.2 B-d and B-e
Test clause no.
Source/Problem 1) Different interpretations may occur about whether to use B-d or B-e to state
the correct insulation level between an F - TYPE APPLIED PART and the
ENCLOSURE .
2) B-e refers to “voltages stressing the insulation”.

What is a hazardous voltage stressing an insulation?
Discussion/ comment B-d insulation is required for F - TYPE APPLIED PARTS .

B-e insulation is required for F - TYPE APPLIED PARTS containing internal voltages,
with a reference voltage equal to the internal voltage.
The second sentence in the statement in 20.3 concerning the reference voltage
between an F - TYPE APPLIED PART and the ENCLOSURE , applies to B-d only and not
to B-e.
WG 14 recommendation B-d is always applicable for a F - TYPE APPLIED PART . U equals maximum RATED
supply voltage; or, 250 V for INTERNALLY POW ERED EQUIPMENT . B ASIC INSULATION
IS required.
In addition B-e is also applicable if there is a voltage in the F - TYPE APPLIED PART .
U equals the voltage stressing the insulation in NORMAL USE including earthing of
any PATIENT connection.
If there is a voltage in the F - TYPE APPLIED PART , values for B-d and B-e are
specified and the higher values are applied and tested.
TR 62296 © IEC:2009(E) – 55 –
2.2.45 Excessive temperatures: Thermocouple instead of resistance method
Requirement, clause no. 42 Excessive temperature
Test clause no. 42
Source/Problem Use of thermocouple instead of resistance method?
Allowable values of Table Xa and Table Xb to be reduced by 10°C if temperature
determined by thermocouples (like Table 4B of IEC 60950-1:2005)?
Discussion/ comment Use of thermocouple may be acceptable (see 42.3.4 ".......unless the windings
are non-uniform or severe complications are involved....")
WG 14 recommendation The allowable maximum temperatures given in Table Xa and Table Xb apply,
regardless of the test method. However, the systematic errors and uncertainties
in any measurement must be considered when comparing the measured value to
the required value.
– 56 – TR 62296 © IEC:2009(E)
2.2.46 Mains fuses and OVER - CURRENT RELEASE s: Fuses in CLASS II EQUIPMENT
Requirement, clause no. 57.6 Mains fuses and OVER - CURRENT RELEASES
Test clause no.
Source/Problem Some test houses do not require fuses in the supply leads for CLASS II appliances
if the whole supply circuit is double-insulated, i.e. double insulation also between
phases. This is not strictly in accordance with the requirements in the standard.
Discussion/ comment The standard currently requires CLASS II EQUIPMENT to be fitted with fuses or
OVER - CURRENT RELEASES in at least one supply lead. The intention was to prevent
interruption of the SUPPLY MAINS in the event of a line to neutral short circuit.
If DOUBLE INSULATION or REINFORCED INSULATION exists between all parts of
opposite polarity within the MAINS PART , then this likelihood is reduced to zero,
unless mains transformer secondary circuit faults create primary fault currents
likely to trip installation over-current protection.
WG 14 recommendation If testing of the EQUIPMENT shows that DOUBLE INSULATION or REINFORCED
INSULATION is indeed present between all parts of opposite polarity within the
MAINS PART , then the omission of fuses or OVER - CURRENT RELEASES would be
acceptable.
NOTE These insulation requirements must be continued up to and within any
component, including any isolation component, e.g. mains transformer, which
should also satisfy the requirements of 57.9.
Y1 line capacitors according to IEC 60384-14 are acceptable in the MAINS PART .
The effect in high powered EQUIPMENT , of short circuit fault conditions in
secondary circuits shall be considered before eliminating fuses or OVER - CURRENT
RELEASE .
TR 62296 © IEC:2009(E) – 57 –
2.2.47 Plug in power supply
Problem raised in: SC 62A/WG 14(Melville)6
Requirement, clause no. Plug-in power supply

6.3 a), 16 e), 56.8, 57.6, 57.8 b)
Test clause no.
Source/Problem Many pieces of MEDICAL ELECTRICAL EQUIPMENT have an INTERNAL ELECTRICAL
POW ER SOURCE . A connection to mains supply is mainly only necessary for
charging the INTERNAL ELECTRICAL POW ER SOURCE . But for this purpose small
power supplies are sufficient which are not integrated in the EQUIPMENT housing.
Non- MEDICAL ELECTRICAL EQUIPMENT has used so-called plug-in power supplies
for a long time. Can this type of power supply also be used for EQUIPMENT ?
UK comment: A number of other standards allow small “plug-top” power supplies
to be protected with only THERMAL CUT - OUTS or other devices (e.g. PTCs). Is this
adequate protection or should all such PSUs for use with medical products
additionally have one or more fuses in the mains circuit?
Discussion/comment During the discussion at least four areas were discovered, where a deviation from
requirements of IEC 60601-1:1988 is possible:
1) PTCs and THERMAL CUT - OUTS instead of mains fuses and/or OVER - CURRENT
RELEASES (57.6) and internal wiring according to 57.8 b);
2) indication if the equipment is energised (6.3 a), 56.8);

3) accessibility of the secondary side (16 e));
4) dimensions and weight when the power supply is integrated in the housing of
the plug.
WG 14 recommendation 1) Apply Recommendation No. 36 if only the transformer in the plug-in power
supply is connected to the mains supply. In the MAINS PART the cross-
sectional area can be less than the minimum required for the POW ER SUPPLY
CORD (57.3 c)), if there is DOUBLE INSULATION or REINFORCED INSULATION
between the opposite polarity. The other requirements of 57.6 apply.
2) WG14 recognizes that the plug-in power supply in itself cannot be
considered as an EQUIPMENT according to IEC 60601-1:1988. The EQUIPMENT
is the combination of the power supply and the unit it supplies and as a
whole must meet IEC 60601-1. This means the plug-in power supply also
has to fulfil requirements of IEC 60601-1:1988.
3) By using item a) 5) and e) 1) of Clause 16, Recommendation No. 8 can be
expanded to all types of connectors. It should be recognized that there may
be SAFETY HAZARDS related to the energy levels associated with accessible
parts. This should be addressed in the risk analysis.
4) When the power supply is integrated in the housing of a plug, constructional
details shall be in accordance with relevant national standards or
International Standards. Dimensions of plugs and sockets are specified in
national standards or International Standards (e.g. Clause 13 of IEC 60884-
1).
All other requirements of IEC 60601-1:1988 apply.
– 58 – TR 62296 © IEC:2009(E)
2.2.48 Connecting cords between EQUIPMENT parts: Other applications
Problem raised in: SC 62A/WG14(Hungary)1
Requirement, clause no. 59.1 f) Applicable requirements

Connecting cords between EQUIPMENT parts…shall be considered as belonging to
the EQUIPMENT and not be subject to requirements for wiring of electrical
installations (in hospitals or otherwise).
Test clause no.
Source/Problem A telephone/patient-entertainment/signalising/monitoring system is intended to be
installed in a hospital. Possible terminal devices are as follows:
– telephone hand pieces (for patients, doctors and nurses);
– push-button for alarming the nursing personnel (by the patient);
– large-surface „push-button“ for alarming lavatory, bath-room, etc.;
– headphones for patients listening to the radio;
– loudspeaker situated under the pillow of patient;
– optically operating infusion (drop) monitoring device (moulded with artificial
resign) situated on the drop-chamber of either a non-electrically or an
electrically operated infusion-device.
Placing of terminal devices is prohibited in „emphasized medically used rooms“
(operating theatre, intensive wardrooms, etc.) by the manufacturer. Central unit
(incl. SMPSU of it) is situated somewhere in a central room of the hospital. The
system covers numerous rooms of the hospital, the overall cable length may be
several thousand meters.
Discussion/comment The system described can neither be considered as MEDICAL ELECTRICAL
EQUIPMENT nor as a MEDICAL ELECTRICAL SYSTEM . If a MEDICAL ELECTRICAL
EQUIPMENT is connected to it, it becomes a MEDICAL ELECTRICAL SYSTEM according
to IEC 60601-1-1.
Attention is drawn to the fact that in some countries nurse calls are seen as
medical equipment.
WG 14 recommendation The system described should be treated as information technology equipment

(ITE) and WG14 recommends that these should have relevant standards
prepared by TC 74 and TC 92.
We are of the opinion that these systems and other non- MEDICAL ELECTRICAL
EQUIPMENT in the PATIENT environment should be covered in a guidance
document such as IEC 60930.
TR 62296 © IEC:2009(E) – 59 –
2.2.49 M ULTIPLE PORTABLE SOCKET- OUTLET
Problem raised in: SC 62A/WG 14(Melville)6 item 7
Requirement, clause no. IEC 60601-1-1:2000, 57.2.201 M ULTIPLE PORTABLE SOCKET - OUTLET
Test clause no.
Source/Problem Detachable power supply cords, and adapters for detachable power supply cords,
are becoming available providing two or more mains connectors, thus enabling
two or more pieces of equipment to be supplied from a single mains plug.
Discussion/comment The use of such cords or adapters creates a SYSTEM as described in 2.201 of
IEC 60601-1-1:2001 similar to a MULTIPLE PORTABLE SOCKET - OUTLET .
WG 14 recommendation If such cords or adapters are equipped with multiple mains connectors, then they
should be treated as MULTIPLE PORTABLE SOCKET - OUTLET as defined in 2.204 of
IEC 60601-1-1:2001 and should comply with the relevant requirements of the
standard, in particular 57.2.201.
– 60 – TR 62296 © IEC:2009(E)
2.2.50 Separation, D EFIBRILLATION - PROOF APPLIED PART : multiple APPLIED PARTS
Problem raised in: SC 62A/WG 14(Melville)3 and (Melville)6 item 8
Requirement, clause no. 17 h) Separation, DEFIBRILLATION - PROOF APPLIED PARTS
Test clause no. 17 h)
Source/Problem Multi-parameter monitoring systems exist in which a number of physiological
functions are monitored by multiple APPLIED PARTS sharing a common PATIENT
CIRCUIT , i.e. not having individual isolation barriers.
Since these physiological functions have different sets of APPLIED PARTS , should,
in the differential-mode test, the test voltage be applied to all APPLIED PARTS , or
can only one set of APPLIED PARTS be designated as defibrillation-proof?
Discussion/comment Where multiple APPLIED PARTS share a common PATIENT CIRCUIT and are not
separated by the CREEPAGE DISTANCE and AIR CLEARANCE specified in 57.10a) 4th
dash. All these APPLIED PARTS must be included in the classification as
DEFIBRILLATION - PROOF APPLIED PARTS . Each of these APPLIED PARTS should be
subject to the test impulse with all other APPLIED PARTS connected to earth.
WG 14 recommendation A PPLIED PARTS may only be separately classified as DEFIBRILLATION - PROOF

APPLIED PARTS if they are electrically separated from other APPLIED PARTS .
If there are other APPLIED PARTS separated from the APPLIED PART under test and
designated for connection to another (second) PATIENT e.g. in sleep study
laboratories, these other APPLIED PARTS should be monitored as unearthed
ACCESSIBLE PARTS during the tests illustrated in Figures 50 and 51.
In 57.10 a) 4th dash, DEFIBRILLATION - PROOF APPLIED PARTS should be taken as

including all parts of that PATIENT CIRCUIT .
E QUIPMENT with more than one function on the same PATIENT CIRCUIT in an
APPLIED PART shall be safe during defibrillation via one of the following methods:
1) An insulation barrier (basic insulation based on a reference voltage equal

mains voltage or 250 V for internally powered equipment) will be inserted
between the different functions.
2) The output connectors of unused applied parts directly at the patient monitor
contain pins recessed by 4,0 mm when measured against the standard test
finger.
3) The testing according to 17 h) (Common-mode test) of the general standard
does not lead to more than 1 V when measured with a foil at the unused
applied part output connector directly at the patient monitor.
TR 62296 © IEC:2009(E) – 61 –
2.2.51 Separation, APPLIED PART: Hand held flexible shafts
Requirement, clause no. 17 Separation, 17 c) APPLIED PART
Test clause no. 17
Source/Problem Hand-held flexible shaft-driven APPLIED PARTS may have parts of the flexible shaft
which are accessible and not connected to protective earth.
This particularly applies to the termination of the flexible shaft which is normally
of metal for durability and strength.
Discussion/comment 17 c) requires that APPLIED PARTS may not have a CONDUCTIVE CONNECTION to
accessible metal parts which are not PROTECTIVELY EARTHED . Hand-held flexible
shafts are deemed likely to come into contact with the OPERATOR or PATIENT
during NORMAL USE . If that is the normal situation, then it seems reasonable to
treat the whole of the flexible shaft as an APPLIED PART .
WG 14 recommendation Hand-held flexible shafts driving an APPLIED PART , e.g. a surgical or dental drill,
may be considered part of the APPLIED PART and therefore the requirements of
item c) of Clause 17 will not apply to the ACCESSIBLE PART of that flexible shaft.
– 62 – TR 62296 © IEC:2009(E)
2.2.52 Protective earthing: No-load voltage of 6 V maximum
Problem raised in: SC 62A/WG 14(Melville)6 item 11 and (London)10 and 17
Requirement, clause no. 18 f) Protective earthing
Test clause no. 18 f)

A current of 25 A or 1,5 times the rated current of the EQUIPMENT , whichever is
greater (± 10 %), from current source with a frequency of 50 Hz or 60 Hz with a
no-load voltage not exceeding 6 V is passed for 5 s to 10 s through the
PROTECTIVE EARTH TERMINAL or the protective earth contact in the APPLIANCE INLET
or the protective earth pin in the MAINS PLUG and each accessible metal part
which could become LIVE in case of failure in BASIC INSULATION .
The voltage drop between the parts described is measured and the impedance
determined from the current and voltage drop. It shall not exceed the values
indicated in this subclause.
Source/Problem E QUIPMENT for example having a rated current of 30 A requires a test current of
1,5 × 30 A. With a maximum impedance of 0,2 Ω, the voltage drop has to be 9 V
(0,2 Ω × 45 A = 9 V). This is in contradiction to the required no-load voltage of
6 V maximum.
Discussion/comment A circuit to the PROTECTIVE EARTH TERMINAL may have zones of higher
impedance, for example due to oxidation of materials. Voltages higher than 6 V
prevent detection of such zones because of their ability to flash through. In this
case, the impedance shall be determined first, using a voltage not exceeding 6 V.
Using low voltages and low currents has a great impact on the accuracy of the
measurement of low impedances. Impedances in the range of 0,1 Ω and 0,2 Ω
then require a sophisticated measuring device.
The relation between rated current of the EQUIPMENT and measuring current is in
order to check cross-sectional areas of protective earth connections. If parts of
the construction or printed circuit boards are used for protective earth
connections, the cross-sectional areas and the ability of carrying short circuit
currents are in doubt.
WG 14 recommendation Measuring the protective earth connection has in fact two reasons. It is to
determine impedance and cross-sectional area of protective earth connections.
For a measuring current of 25 A, both can be done with one measurement.
Requiring a measuring current of more than 25 A, it shall be split up into two
measurements. In this case, the impedance shall be determined first, using a
voltage not exceeding 6 V.
If a cross-sectional area of the protective earth connections cannot be
determined as equal to the one for the phase by measurement of the area, then
measurement with current shall be from a source with a higher voltage than 6 V.
TR 62296 © IEC:2009(E) – 63 –
2.2.53 Foot-operated control devices: Protection against entry of liquids
Requirement, clause no. 56.11 d) second dash

– The electrical switching parts of foot-operated control devices of EQUIPMENT ,
specified by the manufacturer for use in operating rooms, shall be IPX8
according to IEC 60529.
Test clause no. 56.11 d)
Source/Problem Operating rooms are not defined in IEC 60601-1:1988. Can every room where a
medical intervention is carried out be seen as an operating room? If yes, most of
the rooms in a hospital meet this definition. This means nearly every foot-
operated control device has to be IPX8.
Discussion/comment Foot-operated control devices have to be at least IPX1 according to IEC 60529
(56.11 d) first dash).
Every foot-operated control device has a basic protection against entry of liquids.
This is necessary because liquids for example used to clean the floor can affect
insulations of electrical parts. Only those devices where due to the medical
treatment the likelihood of an increased quantity of liquids can occur shall be
taken into account for IPX8.
To combine the requirement for IPX8 with the type of room increases the amount
of foot-operated control devices falling under this requirement unnecessarily.
WG 14 recommendation Change the requirement to read as follows:
The electrical switching parts (including the electrical circuit remote from the
connection/connector to the EQUIPMENT ) of foot-operated control devices of
EQUIPMENT , specified by the manufacturer for use in areas where there is a high
probability of liquids on the floor (e.g. rooms for urological procedures etc.), shall
be IPX8 according to IEC 60529.
– 64 – TR 62296 © IEC:2009(E)
2.2.54 Mains supply transformers
Problem raised in: SC 62A/WG 14(London)4 and (Melville)6 item 3
Requirement, clause no. 57.9, Mains supply transformers
Test clause no. 57.9.1, 57.9.2 and 57.9.4
Source/Problem 'Mains supply transformer' is a not defined term according to IEC 60601-1:1988.
Nevertheless the meaning of the term 'mains' is fixed in conjunction with other
definitions like MAINS PART , MAINS CONNECTOR etc, and describes parts which are
in a circuit with a direct connection to the electrical source or electrical
installation of a building.
Transformers in EQUIPMENT are also very often located in electrical circuits which
cannot be seen as 'mains supply'. What are the requirements for this types of
transformers?
Discussion/comment The requirements in 57.9 were established at a time when no standard for
transformers existed. E QUIPMENT had mainly a transformer in the mains circuit.
Transformers, not being mains supply transformers also have to fulfil
requirements according to IEC 60601-1:1988 if their construction is not according
to an IEC standard for transformers.
Thickness of insulation material is not required in IEC 60601-1:1988 except in
57.9.4 for mains transformers.
WG 14 recommendation Following requirements shall be applied on transformers (except mains supply
transformers and transformers according to an IEC standard).
1) Overheating, short circuit and overload:
Failure of components in the secondary side of the transformer is considered
according to 52.5.9. Resulting temperatures within the values listed in Table
19 if insulation between primary and secondary is an isolation barrier
according to Clause 20.
2) Dielectric strength:
Values according to Clause 20 apply.
Insulation between turns and layers of transformer windings need not be
tested according to 57.9.2 if in the respective circuits no overvoltages are
measured.
3) Construction:
C REEPAGE DISTANCES and AIR CLEARANCES according to 57.10. Requirements
for the thickness of insulation material can be derived either from 57.9.4 or
from the IEC 61558 series.
All other requirements of IEC 60601-1:1988 apply.
TR 62296 © IEC:2009(E) – 65 –
2.2.55 Dielectric strength: Reliability of components to bridge A-a 2 and B-a
Problem raised in: SC 62A/WG 14(Melville)6 item 1
Requirement, clause no. 20.2, A-a 2, B-a
Source/Problem Components between primary and secondary:
D OUBLE INSULATION and REINFORCED INSULATION are defined in 2.3.4 and 2.3.7.
Relevant requirements are in Clause 20 (Dielectric strength) and 57.10
( CREEPAGE DISTANCES and AIR CLEARANCES ). Sometimes it is technically
necessary to bridge these insulations by components (e.g. opto-couplers,
capacitors). What are the requirements for these components?
Discussion/comment Most of the components used to bridge DOUBLE INSULATION or REINFORCED

INSULATION withstand relevant dielectric strength tests. As dielectric strength is a
type test, no evidence is given concerning reliability of the components.
Reliability of components is important to prevent breakdown of insulations during
lifetime of EQUIPMENT . Just a few of the standards addressing requirements for
components relate to reliability. Only components on the basis of such standards
can be used to bridge DOUBLE INSULATION or REINFORCED INSULATION .
WG 14 recommendation Two Y1 capacitors according to IEC 60384-14 in series with the same ratings can
be used to bridge a DOUBLE INSULATION or REINFORCED INSULATION . In addition
each of these capacitors shall be rated for the total voltage across the pair.
– 66 – TR 62296 © IEC:2009(E)
2.2.56 Dielectric strength: A-e in switch mode power supply units (SMPSU)
Problem raised in 62A/WG14(Melville)25

20.1 General requirements for all types of equipment
A-e Between LIVE parts not being parts of SIGNAL INPUT PARTS (SIP) or SIGNAL
OUTPUT PARTS (SOP) and SIGNAL INPUT PARTS or SIGNAL OUTPUT PARTS not
PROTECTIVELY EARTHED ............
No separate investigation is needed if the voltages appearing on the SIGNAL INPUT

PART and/or SIGNAL OUTPUT PART in NORMAL CONDITION and SINGLE FAULT
CONDITION do not exceed SAFETY EXTRA - LOW VOLTAGE .
Source/problem There are two separate problems with this requirement particularly when applied
to EQUIPMENT using switching mode power supply units (SMPSU):
The reference to voltages not exceeding SAFETY EXTRA - LOW VOLTAGE is unclear.
Does this apply to the voltage of the LIVE parts under investigation, or to the
voltages which appear in the SIP/SOP in NORMAL CONDITION and SINGLE FAULT
CONDITION ?
E QUIPMENT using SMPSU is likely to have interference suppression capacitors

from parts of the MAINS PART to PROTECTIVELY EARTHED parts. These components
would normally be rated at the maximum supply voltage and would need to satisfy
the requirements for BASIC INSULATION . Insulation between the MAINS PART and
unearthed parts of SIP/SOP must satisfy one of the methods in Items g) 1-5 of
Clause 17. Most commonly for SPSUs this would be provided within the
transformer(s), in the form of REINFORCED INSULATION , separating the MAINS PART
from the secondary circuits. Application of the test voltage for REINFORCED
INSULATION between an unearthed SIP/SOP and the MAINS PART will result in
overstressing the BASIC INSULATION elements of the MAINS PART , since the
SIP/SOP is also likely to have a conductive path to earth.
Discussion/comment The reference to SAFETY EXTRA - LOW VOLTAGE is presumed to apply to the voltage
limits i.e. < 25 V a.c. rms or < 60 V d.c., rather than to the isolation of the supply.
The exemption is taken to apply to SINGLE FAULT CONDITIONS existing in the
EQUIPMENTrather than fault conditions in EQUIPMENT connected to the SIP/SOP.
In EQUIPMENT using SMPSU, secondary circuits are usually earthed referenced,
as may be the SIP/SOPs. Application of a test voltage for REINFORCED INSULATION
will therefore subject all basic insulation elements in the MAINS PART to this
voltage.
WG14 recommendation 1) Treat the reference to SAFETY EXTRA - LOW VOLTAGE as referring to the voltage
i.e. <25 V a.c. rms or <60 V d.c. and not to the character of the supply.
2) a) Consider only the effect of SINGLE FAULT CONDITIONS in the EQUIPMENT .
This will cover breakdowns of BASIC INSULATION and component failures
between LIVE parts and SIP/SOP.
b) Identify insulation separating parts which are LIVE exceeding SELV from
SIP/SOP and ensure that it complies with one of Items g) 1-5 of Clause
17. Test this insulation with the relevant test voltage.
c) Ensure that the requirements of 20.4 g) are met. This may require
disconnection of the separating part(s) for test purposes, or testing a
separate representative sample of the component(s)
TR 62296 © IEC:2009(E) – 67 –
2.2.57 Dielectric strength: Connection of 12 V dc negative side to ENCLOSURE
IEC SC62A WG14 recommendation No. 57
Problem raised in: BSI 94/50141094.01.27 HCC/64
Requirement, clause no. 16 E NCLOSURES and PROTECTIVE COVERS

a) E QUIPMENT shall be so constructed and enclosed that there is protection against
contact with LIVE parts, …..
19.2 S INGLE FAULT CONDITIONS
a) The EARTH LEAKAGE CURRENT , the ENCLOSURE LEAKAGE CURRENT , the PATIENT
LEAKAGE CURRENT and the PATIENT AUXILIARY CURRENT shall be measured ……
20.1 General requirements for all types of EQUIPMENT

A-a 1 Between LIVE parts and accessible metal parts which are PROTECTIVELY
EARTHED .
Test clause no. 16, 19.4, 20.4
Source/problem Connection of a 12 V d.c. mains negative side to the ENCLOSURE .

Isolation between MAINS PART and ACCESSIBLE PART .
Discussion/comment 10.2.2 address only a.c. power supplies, should include d.c. too, see also
2.12.10,14.1b.
In addition, test with reverse mains as described in 19.1 b), 19.2 a) will lead to a
non-compliance of ENCLOSURE LEAKAGE CURRENT .
WG14 recommendation Connection of either side of d.c. mains to accessible metal parts of THE ENCLOSURE
is not permitted by 14.1 b), at least BASIC INSULATION is required for a CLASS I
EQUIPMENT .
Alternatively other constructions preventing this kind of hazard are allowed.

– 68 – TR 62296 © IEC:2009(E)
2.2.58 Dielectric strength: Voltages appearing on SIP / SOP
Problem raised in: BSI Interpretation I/64-68/158
Requirement, clause no. 20.1 General requirements for all types of EQUIPMENT
A-k Between, in turn, a SIGNAL INPUT PART , a SIGNAL OUTPUT PART and
ACCESSIBLE PARTS not PROTECTIVELY EARTHED .
20.1 a) The voltages appearing on the SIGNAL INPUT PART or SIGNAL OUTPUT PARTS
in NORMAL USE do not exceed SAFETY EXTRA - LOW VOLTAGE .
20.3 Values of test voltages
The reference voltage (U) as used in Table V is the voltage to which the relevant
insulation is subjected in NORMAL USE and at RATED supply voltage or a voltage as
Source/problem It is not clear from the wording of this subclause what the reference voltage for test A-k should be.
If it is the normal WORKING VOLTAGE of the SIGNAL INPUT PART or the SIGNAL OUTPUT PART and that
is less than 50 V, the test voltage is only 500 V, which would barely ensure its suitability to
withstand externally applied MAINS VOLTAGE. If on the other hand the reference voltage is MAINS
VOLTAGE, then the test voltage is 4 kV, which seems excessive for insulation which is only subject
to mains voltage in SINGLE FAULT CONDITION.
Discussion/comment The requirement of DOUBLE INSULATION for 20.1 A-k corresponds to a reference
voltage equal to the W ORKING VOLTAGE in NORMAL USE .
However, for EQUIPMENT with SIP / SOP not designated to be only connected to
equipment (medical or non-medical) in compliance with IEC 60601-1-1, where the
hazard of an external voltage higher than the W ORKING VOLTAGE in the SIP / SOP
exists, the insulation should be according to this external voltage. This external
voltage will be in most cases MAINS VOLTAGE .
WG14 recommendation Insulation should be BASIC INSULATION for 250 V.
There should be a hint in the instruction for use to inform the USER that he has responsibility
in sense of IEC 60601-1-1 for the MEDICAL ELECTRICAL SYSTEM when he connects
equipment to the SIP / SOP of EQUIPMENT.
See also Recommendation 18.
TR 62296 © IEC:2009(E) – 69 –
2.2.59 APPLIED PART : E QUIPMENT without APPLIED PART
Problem raised in: SC62A/WG14(Oslo)10
Requirement, clause no. 2.1.5 A PPLIED PART

A part of the EQUIPMENT which is in NORMAL USE :
– necessarily comes into physical contact with the PATIENT for the EQUIPMENT to
perform its function; or
– can be brought into contact with the PATIENT ; or
– needs to be touched by the PATIENT .
5.2 According to the degree of protection against electric shock:
– APPLIED PART OF TYPE B
– APPLIED PART OF TYPE BF
– APPLIED PART OF TYPE CF
Test clause no. 2.1.5, 5.2, 19
Source/problem A lot of EQUIPMENT has no APPLIED PART (e. g. equipment for radiation). Which
requirements apply?
Discussion/comment M EDICAL ELECTRICAL EQUIPMENT without an APPLIED PART should not be classified in
accordance with the degrees of protection against electric shock. However, the
definition of APPLIED PART includes also parts which can be brought into contact with
the PATIENT in NORMAL USE . In this case these parts are to be treated as APPLIED
PARTS .
WG14 recommendation Apply the relevant requirements of TYPE B APPLIED PARTS to an EQUIPMENT without an
APPLIED PART ,except the requirements for an APPLIED PART .
– 70 – TR 62296 © IEC:2009(E)
2.2.60 Scope: Other than MEDICAL ELECTRICAL EQUIPMENT in contact with the body of a
person
Problem raised in: SC62A/WG14(Munich)3
Requirement, clause no. 1.1 This standard applies to MEDICAL ELECTRICAL EQUIPMENT
2.2.15 M EDICAL ELECTRICAL EQUIPMENT : electrical equipment...which is
determined to be for diagnosis, treatment or observation of a PATIENT under
medical supervision
Test clause no.
Source/problem It is not clear if equipment which is in physical contact with a person to perform
its function or equipment which is used for diagnosis and is not in physical
contact with a person needs to be covered by the standard for MEDICAL
ELECTRICAL EQUIPMENT or by another safety standard.
Discussion/comment – The term ‘under medical supervision’ is not defined.

– There are situations where a person is in physical contact with an equipment
for treatment other than medical (e.g. cosmetic treatment, personal hygiene
equipment).
– There are also situations where a person is not in physical contact with an
equipment and the equipment is being used for diagnostic purposes (e.g.
psychological equipment).
– The risks are practically the same as for a person undergoing medical
treatment.
– In the case where there is no physical connection to the person (e.g. UV
equipment) for treatment reasons or we are dealing with the operator of the
equipment, any other appropriate safety standard could be used.
– A higher degree of safety is obtained by applying IEC 60601-1 for all types of
equipment having a physical connection to the body of a person.
WG14 recommendation Where EQUIPMENT / SYSTEM is for a body treatment other than medical (e.g.
cosmetic treatment), IEC 60601-1 may be used when no other standard exists.
In this case the instruction for use shall clearly indicate that the
EQUIPMENT / SYSTEM is not for medical purposes.
For all other EQUIPMENT / SYSTEMS for medical purposes IEC 60601-1 is mandatory.
TR 62296 © IEC:2009(E) – 71 –
2.2.61 Markings: AC symbol
Problem raised in: SC62A/WG14(Munich)4
Requirement, clause no. 6.1 Markings on the outside of equipment

6.1 g) Type of supply and type of current
6.4 The symbols used must be in accordance with Annex D
Source/problem Instead of the symbol for alternating current (Table DI, 1) often the term “a.c.” is
used.
Discussion/comment The problem was discussed when the third Edition of IEC 60601-1 was drafted.
The term “a.c.” was not seen as an alternative.
The solution from the 3 rd edition can also be taken without any restrictions for the
2 nd edition.
WG14 recommendation For alternating current, the rated frequency in Hertz is sufficient to identify the
type of current. Only “a.c.” is not sufficient.
– 72 – TR 62296 © IEC:2009(E)
2.2.62 Interruption of power supply: Characteristics of interruption
Problem raised in: SC62A/WG14(Oslo)11
Requirement, clause no. 49 Interruption of the power supply

49.2 E QUIPMENT shall be so designed that an interruption and restoration of the
power supply shall not result in a SAFETY HAZARD other than interruption of its
intended function.
Compliance is checked by interruption and restoration of relevant power supplies.
4.7 b) E QUIPMENT for a.c. only shall be tested with a.c. at RATED frequency (if
marked) ± I Hz between 0 Hz and 100 Hz and ± 1 % above 100 Hz.
Test clause no. 7, 19, 42, 49, 52,
Source/problem The above requirement does not describe the characteristics of the interruption
and restoration of the power supply. One example of a specific situation is found
in hospitals where IEC 60364-7-710 (Electrical installations of buildings – Part 7-
710: Requirements for special installations or locations – Medical locations)
applies.
In this case, within 15 s after switching over from the common power supply to
the power supply for safety services, no deviations higher than 5 Hz from the
rated frequency and 10 % from the rated voltage of the safety power supply may
occur.
Discussion/comment In the example above, in an interval of 15 s the frequency can deviate from the
RATED frequency of the EQUIPMENT of much more than stated in the test
conditions. There may not only be a deviation in the frequency but also in the
duration of the interruption of the power supply or in the voltage level. According
to 49.2 the EQUIPMENT has to be safe during the interruption and the following
restoration of the power supply independent of frequency, voltage level or
duration of interruption.
Safety does not only mean physical safety of the equipment but also functional
safety.
IEC 60601-1-2 covers these aspects.
WG14 recommendation The requirements in subclause 36.202.7 of IEC 60601-1-2:2001 should be
applied.
NOTE These requirements also appear in subclause 6.2.7 of IEC 60601-1-2:2007.
TR 62296 © IEC:2009(E) – 73 –
2.2.63 Reference voltage: Different reference voltages in the same circuit
Problem raised in: SC62A/WG14(Tel Aviv)20
Requirement, clause no. 20.3

The reference voltage (U) as used in Table V is the voltage to which the relevant
insulation is subjected in NORMAL USE and at RATED supply voltage………
57.10
57.10 a) The value of the reference voltage (U) is as given in subclause 20.3.
Source/problem The reference voltage (U) as used in Table V is the voltage to which the relevant
insulation is subjected in NORMAL USE and at RATED supply voltage or a voltage
The value of the reference voltage (U) is as given in Subclause 20.3. In case the
reference voltage has a value between those given in Table XVI, the higher of the
two values shall be applied.
Within an SMPSU, different components like switching transformer, opto-couplers
and other single components might bridge the insulation barrier. If reference
voltages will be measured at those components it often leads to different
reference voltages. To apply the higher reference voltage for the whole barrier
would lead to unnecessary higher test values (e.g. CREEPAGE DISTANCES ) at
locations where actually these reference voltages do not exist.
For example, on the terminals of a transformer a voltage of 270 V rms is
measured. On the pins of an opto-coupler in the same isolation barrier a voltage
of 230 V rms is measured. Which reference voltage should be applied for the
opto-coupler?
Discussion/comment The voltage measured on a single component is the reference voltage to define
dielectric strength, CREEPAGE DISTANCES and AIR CLEARANCES for the component
under test.
WG14 recommendation The standard defines minimum requirements. It is permitted to apply different
reference voltages on different components which are part of the same isolation
barrier. However the reference shall never be less than the highest voltage
existing within each side of the concerned isolation barrier.
– 74 – TR 62296 © IEC:2009(E)
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IEC 60601-1-1:2000, Medical electrical equipment - Part 1-1: General requirements for safety
– Collateral standard: Safety requirements for medical electrical systems
IEC 60601-1-2:2001, Medical electrical equipment – Part 1-2: General requirements for safety
– Collateral standard: Electromagnetic compatibility – Requirements and tests
Amendment 1:2004
IEC 60601-1-2:2007, Medical electrical equipment – Part 1-2: General requirements for basic
safety and essential performance – Collateral standard: Electromagnetic compatibility –
Requirements and tests
IEC 60664-1, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60664-3, Insulation coordination for equipment within low-voltage systems – Part 3: Use
of coating, potting or moulding for protection against pollution
IEC 60884-1, Plugs and socket-outlets for household and similar purposes – Part 1: General
requirements
IEC/TR 60930, Guidelines for administrative, medical, and nursing staff concerned with the
safe use of medical electrical equipment and medical electrical systems
TR 62296 © IEC:2009(E) – 75 –
IEC 60950-1:2005, Information technology equipment – Safety – Part 1: General requirements
IEC 61010-1:2001, Safety requirements for electrical equipment for measurement, control,
and laboratory use – Part 1: General requirements
IEC 61558-1, Safety of power transformers, power supplies, reactors and similar products –
Part 1: General requirements and tests
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
– 76 – TR 62296 © IEC:2009(E)
Index of Terms
A M AINS FUSES • 56
A CCESSIBLE PART • 10, 16, 35, 60, 61, 67, M AINS PART • 47, 56, 57, 64, 66, 67
68 M AINS PLUG • 27, 41, 62
A CCOMPANYING DOCUMENTS • 24, 34, 41, 52 M AINS SUPPLY TRANSFORMER • 13, 14, 46,
A IR CLEARANCE • 10, 12, 14, 15, 18, 20, 29, 64
37, 50, 60, 64, 65, 73 M AINS VOLTAGE • 28, 43, 60, 68
A PPLIANCE COUPLER • 41, 51 Marking • 24, 44, 52, 71
A PPLIANCE INLET • 62 M EANS OF PROTECTION • 11, 16
A PPLIED • 16 M EDICAL ELECTRICAL EQUIPMENT • 28, 57,
A PPLIED PART • 10, 35, 43, 45, 47, 48, 60, 58, 70
61, 69 Non- • 28, 57, 58
B M EDICAL ELECTRICAL SYSTEM • 68
B ASIC INSULATION • 11, 16, 20, 27, 35, 49, M EDICAL ELECTRICAL SYSTEM • 58, 59, 68
54, 60, 62, 66, 67, 68 M EDICAL ELECTRICAL SYSTEM • 70
Batteries • 24, 40, 53 Medical supervision • 70
C M ULTIPLE PORTABLE SOCKET - OUTLET • 59
C LASS I EQUIPMENT • 39, 67 N
C LASS II EQUIPMENT • 43, 56 Nominal
C OMPONENT • 10, 17, 30, 47 Capacitance • 11
C ONDUCTIVE CONNECTION • 61 N ORMAL CONDITION • 10, 11, 16, 25, 30, 41,
C ONNECTING CORDS • 58 42, 45, 48, 66
C ONSTRUCTION • 49 N ORMAL USE • 25, 28, 37, 42, 54, 61, 68,
C REEPAGE DISTANCE • 10, 12, 14, 15, 18, 69, 73
20, 29, 37, 50, 60, 64, 65, 73 O
D O PERATOR • 18, 24, 40, 61
D EFIBRILLATION- PROOF APPLIED PART • 60 O VER - CURRENT RELEASE • 17, 56, 57
Dielectric strength • 11, 13, 15, 16, 27, 28, O VERHEATING • 38
29, 35, 37, 50, 51, 54, 64, 65, 66, 67, 68, O VERLOAD
73 Test • 13, 14
D OUBLE INSULATION • 11, 17, 27, 35, 37, 49, Overvoltage • 64
56, 57, 65, 68 P
E P ATIENT • 18, 48, 54, 60, 61, 69, 70
E ARTH LEAKAGE CURRENT • 42, 67 Environment • 58
E NCLOSURE • 18, 22, 27, 32, 43, 48, 54, 67 Monitor • 60
E NCLOSURE LEAKAGE CURRENT • 10, 18, 27, P ATIENT AUXILIARY CURRENT • 10, 26, 29,
42, 43, 67 42, 67
E QUIPMENT • 10, 17, 20, 22, 25, 26, 27, 28, P ATIENT CIRCUIT • 60
29, 30, 31, 32, 34, 35, 37, 39, 40, 41, 42, P ATIENT LEAKAGE CURRENT • 10, 19, 42, 43,
43, 44, 45, 47, 48, 50, 51, 56, 57, 58, 60, 67
62, 63, 64, 65, 66, 67, 68, 72 P ERMANENTLY INSTALLED EQUIPMENT • 41
Parts • 44, 58 Non- • 41
E XCESSIVE TEMPERATURE • 25, 45, 55 Plug in power supply • 57
F P OWER SUPPLY CORD • 51, 57
F OOT - OPERATED CONTROL DEVICES • 63 P RECONDITIONING • 34
F- TYPE APPLIED PART • 54 P ROTECTIVE COVER • 67
I P ROTECTIVE EARTH CONDUCTOR • 27, 39
Instructions for use • 18, 28, 30, 39, 40, P ROTECTIVE EARTH TERMINAL • 62
41, 45, 48, 68, 70 P ROTECTIVE EARTHING • 62
I NTERNAL ELECTRICAL POWER SOURCE • 39, P ROTECTIVELY EARTHED • 61, 66, 67, 68
53, 57 PTC • 46, 57
I NTERNALLY POWERED EQUIPMENT • 19, 43, R
54, 60 R ATED
L Capacitance • 11
Lampholder • 22 Frequency • 72
Lanpholder • 22 Mains voltage • 43
L EAKAGE CURRENT • 10, 11, 16, 26, 28, 29, Supply voltage • 19, 37, 54, 68, 73
42 Reference voltage • 29, 37, 54, 60, 68, 73
L IVE • 10, 16, 18, 22, 27, 35, 41, 62, 66, 67 R EINFORCED INSULATION • 17, 35, 37, 49,
M 56, 57, 65, 66
M AINS CONNECTOR • 27, 51, 64
TR 62296 © IEC:2009(E) – 77 –
S Polyphase • 41
S AFETY EXTRA - LOW VOLTAGE • 18, 28, 43, Symbol • 41
66, 68 T
S AFETY HAZARD • 13, 17, 30, 34, 35, 57, 72 Test finger • 60
S EPARATION • 10, 12, 21, 60, 61 Test voltage • 37, 60, 66, 68
S IGNAL INPUT PART • 18, 28, 37, 43, 66, 68 T HERMAL CUT - OUT • 46, 57
S IGNAL OUTPUT PART • 18, 28, 37, 43, 66, T OOL • 22, 24
68 T YPE B APPLIED PART • 69
S INGLE FAULT CONDITION • 10, 11, 16, 27, T YPE BF APPLIED PART • 69
28, 30, 35, 43, 45, 48, 66, 67, 68 T YPE CF APPLIED PART • 69
SMPSU • 29, 58, 66, 73 U
S TATIONARY EQUIPMENT • 51 U SER • 40, 52, 68
S UPPLEMENTARY INSULATION • 11, 35 W
S UPPLY MAINS • 17, 19, 26, 27, 39, 41, 56 W ORKING VOLTAGE • 11, 28, 68
___________
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ELECTROTECHNICAL
COMMISSION
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PO Box 131
CH-1211 Geneva 20
Switzerland
Tel: + 41 22 919 02 11
Fax: + 41 22 919 03 00
info@iec.ch
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2.2.37Components and general assembly: Reliability of components .................. 47

INTERNATIONAL ELECTROTECHNICAL COMMISSION

CONSIDERATIONS OF UNADDRESSED SAFETY ASPECTS

The text of this technical report is based on the following documents:

Enquiry draft Report on voting

A bilingual version of this technical report may be issued at a later date.

IMPORTANT NOTE: Per the 62A decision at Sydney (see RM3755/SC62A,

This recommendation/interpretation is the result of considerations by a group

CONSIDERATIONS OF UNADDRESSED SAFETY ASPECTS

1 Scope and object

This technical report contains a series of recommendations developed by an expert working

– manufacturers of MEDICAL ELECTRICAL EQUIPMENT ;

The object of this technical report is to make the recommendations/interpretations developed

2.1 Summary of all recommendations prepared by SC 62A/WG 14

6.1 g) 061 Markings: AC symbol 71

57.2.201 049 M ULTIPLE PORTABLE SOCKET - OUTLET 59

2.2 Recommendation sheets

2.2.1 Separation: Reliability of component impedance

IEC/SC 62A/WG14 Recommendation No. 1

Problem raised in: SC 62A/WG 14(Canada)1, 2 and 4

Requirement, clause no. 17 Separation

WG 14 recommendation If a capacitor (protective impedance) is used, the following applies:

According to the standard, DOUBLE INSULATION is not to be short circuited. D OUBLE

2.2.2 Separation: Non-complying creepage distance and air clearances

IEC/SC 62A/WG14 Recommendation No. 2

Problem raised in: SC 62A/WG 14(Canada)2

Recommendation deleted: text implemented in recommendation No. 1

2.2.3 Mains supply transformers: Overload test

IEC/SC 62A/WG14 Recommendation No. 3

Problem raised in: SC 62A/WG 14(Canada)8

Requirement, clause no. 57.9.1b) Mains supply transformers: Overload test

Test clause no.

2.2.4 Mains supply transformers: Short circuit and overload tests

IEC/SC 62A/WG14 Recommendation No. 4

Problem raised in: SC 62A/WG 14(Canada)9

Test clause no.

Discussion/comment Inspection of the transformer arrangements will be necessary to determine the

2.2.5 Creepage distance and air clearances: Values

IEC/SC 62A/WG14 Recommendation No. 5

Problem raised in: SC 62A/WG 14(Canada)10

Test clause no.

Discussion/comment At present the concept of distance through insulation (e.g. in an opto-coupler or

WG 14 recommendation There is no additional recommendation to the already required dielectric strength

2.2.6 Dielectric strength

IEC/SC 62A/WG14 Recommendation No. 6

Problem raised in: Fax from M.M. Stuchi (IMQ)

Requirement, clause no. 20 Dielectric strength.

Test clause no.

2.2.7 Failure of components: Evidence of reliability

IEC/SC 62A/WG14 Recommendation No. 7

Problem raised in: SC 62A/WG 14(Sweden)13

Rationale 57.7: Interference suppressors may be connected on the SUPPLY MAINS

2.2.8 E NCLOSURES and protective covers

IEC/SC 62A/WG 14 Recommendation No. 8

Problem raised in: SC 62A/WG 14(Sweden)14