IEC TS 62850:2013

IEC/TS 62850 ®
Edition 1.0 2013-02
TECHNICAL
SPECIFICATION
SPÉCIFICATION
TECHNIQUE
Safety requirements for electrical equipment for measurement, control, and
laboratory use –
General requirements for equipment intended to be used in educational
establishments by children
Règles de sécurité pour appareils électriques de mesurage, de régulation et de
laboratoire –
Règles générales pour appareils destinés à une utilisation dans les
établissements scolaires par des enfants

IEC/TS 62850:2013
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IEC/TS 62850 ®
Edition 1.0 2013-02
TECHNICAL
SPECIFICATION
SPÉCIFICATION
TECHNIQUE
Safety requirements for electrical equipment for measurement, control, and

laboratory use –
General requirements for equipment intended to be used in educational

establishments by children
Règles de sécurité pour appareils électriques de mesurage, de régulation et de

laboratoire –
Règles générales pour appareils destinés à une utilisation dans les

établissements scolaires par des enfants

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XH
ICS 19.080 ISBN 978-2-83220-655-3

– 2 – TS 62850 © IEC:2013
CONTENTS
FOREWORD . 10
INTRODUCTION . 12
1 Scope and object . 13
1.1 Scope . 13
1.1.1 Equipment included in scope . 13
1.1.2 Equipment excluded from scope . 13
1.1.3 Computing equipment . 14
1.2 Object . 14
1.2.1 Aspects included in scope . 14
1.2.2 Aspects excluded from scope . 15
1.3 Verification . 15
1.4 Environmental conditions . 15
1.4.1 Normal environmental conditions . 15
1.4.2 Extended environmental conditions . 15
2 Normative references . 16
3 Terms and definitions . 18
3.1 Equipment and states of equipment . 18
3.2 Parts and accessories . 18
3.3 Quantities . 19
3.4 Tests . 20
3.5 Safety terms . 20
3.6 Insulation . 22
4 Tests . 23
4.1 General . 23
4.2 Sequence of tests . 24
4.3 Reference test conditions . 24
4.3.1 Environmental conditions . 24
4.3.2 State of equipment . 24
4.4 Testing in SINGLE FAULT CONDITION . 26
4.4.1 General . 26
4.4.2 Application of fault conditions . 26
4.4.3 Duration of tests . 29
4.4.4 Conformity after application of fault conditions. 29
5 Marking and documentation . 30
5.1 Marking . 30
5.1.1 General . 30
5.1.2 Identification . 30
5.1.3 MAINS supply . 30
5.1.4 Fuses . 32
5.1.5 TERMINALS, connections and operating devices . 32
5.1.6 Switches and circuit-breakers . 33
5.1.7 Equipment protected by DOUBLE INSULATION or REINFORCED
INSULATION . 33
5.1.8 Field-wiring TERMINAL boxes . 34
5.2 Warning markings . 34
5.3 Durability of markings . 34
5.4 Documentation . 35

TS 62850 © IEC:2013 – 3 –
5.4.1 General . 35
5.4.2 Equipment RATINGS . 35
5.4.3 Equipment installation . 36
5.4.4 Equipment operation. 36
5.4.5 Equipment maintenance and service . 37
5.4.6 Integration into systems or effects resulting from special conditions . 37
6 Protection against electric shock . 38
6.1 General . 38
6.1.1 Requirements . 38
6.1.2 Exceptions . 38
6.2 Determination of ACCESSIBLE parts . 38
6.2.1 General . 38
6.2.2 Examination . 39
6.2.3 Not used Openings above parts that are HAZARDOUS LIVE . 39
6.2.4 Not used Openings for pre-set controls . 39
6.2.5 Additional determination for all openings except TERMINALS . 40
6.3 Limit values for ACCESSIBLE parts. 40
6.3.1 Levels in NORMAL CONDITION . 40
6.3.2 Levels in SINGLE FAULT CONDITION. 40
6.4 Primary means of protection . 43
6.4.1 General . 43
6.4.2 ENCLOSURES and PROTECTIVE BARRIERS. 43
6.4.3 BASIC INSULATION . 43
6.4.4 Impedance. 43
6.5 Additional means of protection in case of SINGLE FAULT CONDITIONS . 43
6.5.1 General . 43
6.5.2 PROTECTIVE BONDING . 44
6.5.3 SUPPLEMENTARY INSULATION and REINFORCED INSULATION . 47
6.5.4 PROTECTIVE IMPEDANCE . 47
6.5.5 Automatic disconnection of the supply . 48
6.5.6 Current- or voltage-limiting device . 48
6.6 Connections to external circuits . 48
6.6.1 General . 48
6.6.2 TERMINALS for external circuits . 49
6.6.3 Circuits with TERMINALS which are HAZARDOUS LIVE . 49
6.6.4 TERMINALS for stranded conductors . 49
6.7 Insulation requirements . 50
6.7.1 The nature of insulation . 50
6.7.2 Insulation for MAINS CIRCUITS of OVERVOLTAGE CATEGORY II with a
nominal supply voltage up to 300 V . 52
6.7.3 Insulation for secondary circuits derived from MAINS CIRCUITS of
OVERVOLTAGE CATEGORY II up to 300 V . 56
6.8 Procedure for voltage tests . 61
6.8.1 General . 61
6.8.2 Humidity preconditioning . 62
6.8.3 Test procedures . 63
6.9 Constructional requirements for protection against electric shock . 63
6.9.1 General . 63
6.9.2 Insulating materials . 64

– 4 – TS 62850 © IEC:2013
6.9.3 Colour coding . 64
6.10 Connection to the MAINS supply source and connections between parts of
equipment . 64
6.10.1 MAINS supply cords . 64
6.10.2 Fitting of non-detachable MAINS supply cords . 65
6.10.3 Plugs and connectors . 67
6.11 Disconnection from supply source . 67
6.11.1 General . 67
6.11.2 Exceptions . 67
6.11.3 Requirements according to type of equipment . 67
6.11.4 Disconnecting devices . 68
7 Protection against mechanical HAZARDS . 69
7.1 General . 69
7.2 Sharp edges . 69
7.3 Moving parts . 69
7.3.1 General . 69
7.3.2 Exceptions . 69
7.3.3 RISK assessment for mechanical HAZARDS to body parts . 70
7.3.4 Limitation of force and pressure. 71
7.3.5 Gap limitations between moving parts . 71
7.4 Stability . 73
7.5 Provisions for lifting and carrying. 74
7.5.1 General . 74
7.5.2 Handles and grips. 74
7.5.3 Lifting devices and supporting parts . 74
7.6 Wall mounting . 75
7.7 Expelled parts . 75
8 Resistance to mechanical stresses . 75
8.1 General . 75
8.2 ENCLOSURE rigidity tests . 76
8.2.1 Static test . 76
8.2.2 Impact test . 77
8.3 Drop test . 78
8.3.1 Equipment other than HAND-HELD EQUIPMENT and DIRECT PLUG-IN
EQUIPMENT . 78
8.3.2 HAND-HELD EQUIPMENT and DIRECT PLUG-IN EQUIPMENT . 78
9 Protection against the spread of fire . 78
9.1 General . 78
9.2 Eliminating or reducing the sources of ignition within the equipment . 80
9.3 Containment of fire within the equipment, should it occur . 80
9.3.1 General . 80
9.3.2 Constructional requirements . 80
9.4 Limited-energy circuit . 83
9.5 Requirements for equipment containing or using flammable liquids . 84
9.6 Overcurrent protection . 84
9.6.1 General . 84
9.6.2 PERMANENTLY CONNECTED EQUIPMENT . 85
9.6.3 Other equipment . 85
10 Equipment temperature limits and resistance to heat . 85

TS 62850 © IEC:2013 – 5 –
10.1 Surface temperature limits for protection against burns . 85
10.2 Temperatures of windings . 86
10.3 Other temperature measurements . 87
10.4 Conduct of temperature tests . 87
10.4.1 General . 87
10.4.2 Temperature measurement of heating equipment . 87
10.4.3 Equipment intended for installation in a cabinet or a wall . 88
10.5 Resistance to heat . 88
10.5.1 Integrity of CLEARANCES and CREEPAGE DISTANCES . 88
10.5.2 Non-metallic ENCLOSURES . 88
10.5.3 Insulating material . 88
11 Protection against HAZARDS from fluids . 89
11.1 General . 89
11.2 Cleaning . 90
11.3 Spillage . 90
11.4 Overflow . 90
11.5 Battery electrolyte . 90
11.6 Specially protected equipment . 91
11.7 Fluid pressure and leakage . 91
11.7.1 Maximum pressure . 91
11.7.2 Leakage and rupture at high pressure . 91
11.7.3 Leakage from low-pressure parts . 92
11.7.4 Overpressure safety device . 92
12 Protection against radiation, including laser sources, and against sonic and
ultrasonic pressure . 92
12.1 General . 92
12.2 Equipment producing ionizing radiation . 92
12.2.1 Ionizing radiation . 92
12.2.2 Accelerated electrons . 94
12.3 Ultraviolet (UV) Optical radiation . 94
12.4 Microwave radiation . 95
12.5 Sonic and ultrasonic pressure . 95
12.5.1 Sound level . 95
12.5.2 Ultrasonic pressure . 95
12.6 Laser sources. 96
13 Protection against liberated gases and substances, explosion and implosion . 96
13.1 Poisonous and injurious gases and substances . 96
13.2 Explosion and implosion . 97
13.2.1 Components . 97
13.2.2 Batteries and battery charging . 97
13.2.3 Implosion of cathode ray tubes . 97
14 Components and subassemblies . 98
14.1 General . 98
14.2 Motors . 99
14.2.1 Motor temperatures . 99
14.2.2 Series excitation motors . 99
14.3 Overtemperature protection devices . 100
14.4 Fuse holders . 100
14.5 MAINS voltage selection devices . 100

– 6 – TS 62850 © IEC:2013
14.6 MAINS transformers tested outside equipment . 100
14.7 Printed wiring boards. 101
14.8 Circuits or components used as TRANSIENT OVERVOLTAGE limiting devices . 101
14.9 Small components . 102
15 Protection by interlocks . 102
15.1 General . 102
15.2 Prevention of reactivating . 102
15.3 Reliability . 102
16 HAZARDS resulting from application . 103
16.1 REASONABLY FORESEEABLE MISUSE . 103
16.2 Ergonomic aspects . 103
17 RISK assessment . 103
Annex A (normative) Measuring circuits for touch current (see 6.3). 105
Annex B (normative) Standard test fingers (see 6.2) . 109
Annex C (normative) Measurement of CLEARANCES and CREEPAGE DISTANCES . 112
Annex D (normative) Parts between which insulation requirements are specified (see
6.4 and 6.5.3) . 116
Annex E (informative) Guideline for reduction of POLLUTION DEGREES . 119
Annex F (normative) ROUTINE TESTS. 120
Annex G (informative) Leakage and rupture from fluids under pressure . 122
Annex H (normative) Qualification of conformal coatings for protection against
POLLUTION . 127
Annex I (informative) Line-to-neutral voltages for common MAINS supply systems . 130
Annex J (informative) RISK assessment . 131
Annex K (normative) Insulation requirements not covered by 6.7 . 134
Annex L (informative) Index of defined terms . 156
Bibliography . 158

Figure 1 – Measurements through openings in ENCLOSURES . 39
Figure 2 – Maximum duration of short-term ACCESSIBLE voltages in SINGLE FAULT
CONDITION (see 6.3.2 a)) . 41
Figure 3 – Capacitance level versus voltage in NORMAL CONDITION and SINGLE FAULT
CONDITION (see 6.3.1 c) and 6.3.2 c)) . 42
Figure 4 – Acceptable arrangement of protective means against electric shock . 44
Figure 5 – Examples of binding screw assemblies . 46
Figure 6 – Distance between conductors on an interface between two layers . 54
Figure 7 – Distance between adjacent conductors along an interface of two inner
layers . 54
Figure 8 – Distance between adjacent conductors located between the same two
layers . 55
Figure 9 – Detachable MAINS supply cords and connections . 65
Figure 10 – Impact test using a sphere . 77
Figure 11 – Flow chart to explain the requirements for protection against the spread of
fire . 79
Figure 12 – Baffle . 82
Figure 13 – Area of the bottom of an ENCLOSURE to be constructed as specified in
9.3.2 c) 1) . 82

TS 62850 © IEC:2013 – 7 –
Figure 14 – Ball-pressure test apparatus . 89
Figure 15 – Flow chart for conformity options 14.1 a), b), c) and d) . 99
Figure 16 – Cylinder for checking the size of small components . 102
Figure A.1 – Measuring circuit for a.c. with frequencies up to 1 MHz and for d.c. . 105
Figure A.2 – Measuring circuits for sinusoidal a.c. with frequencies up to 100 Hz and
for d.c. . 106
Figure A.3 – Current measuring circuit for electrical burns . 107
Figure A.4 – Current measuring circuit for wet contact . 108
Figure B.1 – Rigid test finger . 109
Figure B.2 – Jointed test finger . 110
Figure B.3 – Jointed test probe for equipment intended to be used by CHILDREN . 111
Figure C.1 – Examples of methods of measuring CLEARANCES and CREEPAGE
DISTANCES . 115
Figures D.1 a) to d) – Protection between HAZARDOUS LIVE circuits and ACCESSIBLE
parts . 117
Figures D.1 e) to h) – Protection between HAZARDOUS LIVE circuits and circuits which
ACCESSIBLE external TERMINALS . 117
Figures D.2 a) and b) – Protection between a HAZARDOUS LIVE internal circuit and an
ACCESSIBLE part which is not bonded to other ACCESSIBLE parts . 118
Figures D.2 c) and d) – Protection between a HAZARDOUS LIVE primary circuit and
circuits which have ACCESSIBLE external TERMINALS . 118
Figure D.3 – Protection of external ACCESSIBLE TERMINALS of two HAZARDOUS LIVE
circuits . 118
Figure G.1 – Conformity verification process (see G.2) . 123
Figure H.1 – Test sequence and conformity . 129
Figure J.1 – Iterative process of RISK assessment and RISK reduction . 131
Figure J.2 – RISK reduction . 132
Figure K.1 – Distance between conductors on an interface between two layers . 139
Figure K.2 – Distance between adjacent conductors along an interface of an inner
layer . 139
Figure K.3 – Distance between adjacent conductors located between the same two
layers . 140
Figure K.4 – Example of recurring peak voltage . 153

Table 1 – Symbols . 31
Table 2 – Tightening torque for binding screw assemblies . 46
Table 3 – Multiplication factors for CLEARANCES of equipment RATED for operation at
altitudes up to 5 000 m . 51
Table 4 – CLEARANCES and CREEPAGE DISTANCES for MAINS CIRCUITS of OVERVOLTAGE
CATEGORY II up to 300 V . 53
Table 5 – Test voltages for solid insulation in MAINS CIRCUITS of OVERVOLTAGE
CATEGORY II up to 300 V . 53
Table 6 – CLEARANCES and test voltages for secondary circuits derived from MAINS
CIRCUITS of OVERVOLTAGE CATEGORY II up to 300 V . 57
Table 7 – CREEPAGE DISTANCES for secondary circuits . 58
Table 8 – Minimum values for distance or thickness (see 6.7.3.4.2 to 6.7.3.4.4) . 60
Table 9 – Distances between TERMINALS and foil . 61

– 8 – TS 62850 © IEC:2013
Table 10 – Correction factors according to test site altitude for test voltages for
CLEARANCES . 62
Table 11 – Values for physical tests on cord anchorages . 66
Table 12 – Protective measures against mechanical HAZARDS to body parts. 70
Table 13 – Minimum maintained gaps to prevent crushing for different body parts . 72
Table 14 – Maximum gaps to prevent access for different body parts . 73
Table 15 – Impact energy levels, test height and corresponding IK codes . 78
Table 16 – Acceptable perforation of the bottom of an ENCLOSURE . 81
Table 17 – Limits of maximum available current . 83
Table 18 – Values for overcurrent protection devices . 84
Table 19 – Surface temperature limits in NORMAL CONDITION . 86
Table 20 – Maximum temperatures for insulation material of windings . 87
Table 21 – Lamp or lamp systems considered photobiologically safe . 94
Table 22 – Lamp or lamp systems considered photobiologically conditionally safe . 94
Table 23 Table 21 – Impulse withstand voltages for OVERVOLTAGE CATEGORY II . 101
Table C.1 – Dimensions of X. 112
Table E.1 – Environmental situations . 119
Table E.2 – Reduction of POLLUTION DEGREES . 119
Table F.1 – Test voltages for ROUTINE TESTS of MAINS CIRCUITS . 121
Table G.1 – Test pressures for equipment with pressures above 14 MPa . 125
Table H.1 – Test parameters, test conditions and test procedures . 128
Table I.1 – Line-to-neutral voltages for common MAINS supply systems . 130
Table J.1 – Severity of harm . 133
Table J.2 – Probability of harm . 133
Table J.3 – RISK category . 133
Table K.1 – Multiplication factors for CLEARANCES for equipment RATED for operation at
altitudes up to 5 000 m . 135
Table K.2 – CLEARANCES and CREEPAGE DISTANCES for MAINS CIRCUITS of OVERVOLTAGE
CATEGORY II above 300 V . 135
Table K.3 – CLEARANCES and CREEPAGE DISTANCES for MAINS CIRCUITS of OVERVOLTAGE
CATEGORY III . 136
Table K.4 – CLEARANCES and CREEPAGE DISTANCES for MAINS CIRCUITS of OVERVOLTAGE
CATEGORY IV . 136
Table K.5 – Test voltages for solid insulation in MAINS CIRCUITS of OVERVOLTAGE
CATEGORY II above 300 V . 137
Table K.6 – Test voltages for solid insulation in MAINS CIRCUITS of OVERVOLTAGE
CATEGORY III . 137
Table K.7 – Test voltages for solid insulation in MAINS CIRCUITS of OVERVOLTAGE
CATEGORY IV . 138
Table K.8 – Test voltages for testing long-term stress of solid insulation in MAINS
CIRCUITS . 138
Table K.9 – Minimum values for distance or thickness of solid insulation . 139
Table K.10 – CLEARANCES and test voltages for secondary circuits derived from MAINS
CIRCUITS of OVERVOLTAGE CATEGORY II above 300 V . 142
Table K.11 – CLEARANCES and test voltages for secondary circuits derived from MAINS
CIRCUITS of OVERVOLTAGE CATEGORY III . 143

TS 62850 © IEC:2013 – 9 –
Table K.12 – CLEARANCES and test voltages for secondary circuits derived from MAINS
CIRCUITS of OVERVOLTAGE CATEGORY IV . 144
Table K.13 – CREEPAGE DISTANCES for secondary circuits . 145
Table K.14 – Minimum values for distance or thickness (see K.2.4.2 to K.2.4.4) . 147
Table K.15 – CLEARANCE values for the calculation of K.3.2 .
...