IEC TR 62296:2009

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

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 978-2-88910-665-3
– 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 ENCLOSURES and protective covers .18
2.2.9 INTERNALLY 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 ENCLOSURES 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 ENCLOSURE 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 LEAKAGE 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: EQUIPMENT containing floating circuits .35
2.2.26 General requirements for tests: Measurement uncertainty .36
2.2.27 CREEPAGE 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 SINGLE FAULT CONDITION: ENCLOSURE 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: APPLIED 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 –
2.2.37 Components and general assembly: Reliability of components .47
2.2.38 Definition of APPLIED PART: EQUIPMENT worn by PATIENTS .48
2.2.39 Construction: Triple insulated winding wire .49
2.2.40 CREEPAGE DISTANCES and AIR CLEARANCES: Dielectric strength test
versus CREEPAGE DISTANCES and AIR CLEARANCES .50
2.2.41 CREEPAGE DISTANCES and AIR CLEARANCES: Dielectric strength test
versus CREEPAGE DISTANCES and AIR CLEARANCES – POWER SUPPLY
CORDS.51
2.2.42 ACCOMPANYING DOCUMENTS: on CD-ROM or electronic file format .52
2.2.43 INTERNAL 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 RELEASEs: 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 MULTIPLE PORTABLE SOCKET-OUTLET.59
2.2.50 Separation, DEFIBRILLATION-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-a 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 APPLIED PART: EQUIPMENT 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
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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
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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.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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-
nd
of the 2
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: EQUIPMENT worn by PATIENTS 48
2.1.5 APPLIED PART: EQUIPMENT without APPLIED PART 69
3.6 f) Failure of an electrical component: Time periodicity for detection 30
4 General requirements for tests: Measurement uncertainty 36
4.10 024 Humidity preconditioning treatment: Exception from requirement 34

– 8 – TR 62296 © IEC:2009(E)
Subclause
nd Recom-
of the 2
mendation Contents Page
edition of
number
IEC 60601-1
6.1 g) 061 Markings: AC symbol 71
6.1 n) Marking on the outside of EQUIPMENT: Type and rating of fuses 44
6.2 d) Batteries not intended to be changed by OPERATOR: Lithium batteries 24
6.8.1 042 ACCOMPANYING 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) 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 ENCLOSURES and protective covers: Accessibility of SIP/SOPs 18
16 017 ENCLOSURE and protective covers: EQUIPMENT in ambulances 27
16 d) 012 ENCLOSURES 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 LEAKAGE CURRENTS: Presence of 45 kΩ resistor in Figure 21 33
19.1 016 Continuous LEAKAGE CURRENTS: Different SUPPLY MAINS 26
19.2 c) 033 SINGLE FAULT CONDITION: ENCLOSURE LEAKAGE CURRENT from INTERNALLY 43
POWERED 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 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: APPLIED 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 INTERNAL ELECTRICAL POWER SOURCE: Requirements for lithium batteries 53

TR 62296 © IEC:2009(E) – 9 –
Subclause
nd Recom-
of the 2
mendation Contents Page
edition of
number
IEC 60601-1
57.1 a) 031 Isolation from the SUPPLY MAINS: Symbol for single pole switch 41
57.10 CREEPAGE DISTANCES and AIR CLEARANCES: Interpolated values 37
57.10 a) CREEPAGE DISTANCES and AIR CLEARANCES: Values for material 15
57.10 d) 010 CREEPAGE DISTANCES and AIR CLEARANCES: Values under 1 mm 20
57.10 d) 040 CREEPAGE DISTANCES and AIR CLEARANCES: Dielectric strength test versus 50
CREEPAGE DISTANCES and AIR CLEARANCES
57.2.201 MULTIPLE 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 RELEASEs: 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) APPLIED 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) ACCESSIBLE 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 –
If a capacitor (protective impedance) is used, the following applies:
WG 14 recommendation
– 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 WORKING 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 WORKING VOLTAGE across the pair
and shall have the same NOMINAL capacitance.
According to the standard, DOUBLE INSULATION is not to be short circuited. DOUBLE
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.
LEAKAGE 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
IEC/SC 62A/WG14 Recommendation No. 2
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
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.
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
IEC/SC 62A/WG14 Recommendation No. 4
Problem raised in: SC 62A/WG 14(Canada)9
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
IEC/SC 62A/WG14 Recommendation No. 5
Problem raised in: SC 62A/WG 14(Canada)10
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
IEC/SC 62A/WG14 Recommendation No. 6
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.
ACCESSIBLE 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
IEC/SC 62A/WG14 Recommendation No. 7
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 ENCLOSURES and protective covers
IEC/SC 62A/WG 14 Recommendation No. 8
Problem raised in: SC 62A/WG 14(Sweden)14
Requirement, clause no. 16 ENCLOSURES 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 INTERNALLY POWERED EQUIPMENT: 110 % of the maximum supply voltage
IEC/SC 62A/WG 14 Recommendation No. 9
Problem raised in: SC 62A/WG 14(Sweden)15
Requirement, clause no. 19.4 h) Measurement of PATIENT LEAKAGE CURRENT
Test clause no.
19.4 h) 7) and 8) for INTERNALLY POWERED 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 POWERED 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 POWERED EQUIPMENT may be designated for use in areas with
specific maximum supply voltages less than 230 V.
WG 14 recommendation INTERNALLY POWERED EQUIPMENT provided with a means of connection to a supply
mains shall be tested at 110 % of the maximum RATED supply voltage.
INTERNALLY POWERED 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
IEC/SC 62A/WG 14 Recommendation No. 10
Problem raised in: SC 62A/WG 14(Sweden)16
Requirement, clause no. 57.10. CREEPAGE 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
EQUIPMENT would only be used in an
IEC 60601-1 the assumption was made that
environment equal to pollution degree 2 of IEC 60664-1.
WG 14 recommendation AIR 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
IEC/SC 62A/WG 14 Recommendation No. 11
Problem raised in: SC 62A/WG 14(Canada)4
Recommendation deleted: text implemented in recommendation No. 1

– 22 – TR 62296 © IEC:2009(E)
2.2.12 ENCLOSURES and PROTECTIVE COVERS: Lampholder/switching device
IEC/SC 62A/WG 14 Recommendation No. 12
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) ENCLOSURES 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
IEC/SC 62A/WG 14 Recommendation No. 13
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 sh
...