IEC 61558-2-16:2021

IEC 61558-2-16 ®
Edition 2.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-16: Particular requirements and tests for switch mode power supply units
and transformers for switch mode power supply units for general applications

Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et
combinaisons de ces éléments –
Partie 2-16: Exigences particulières et essais pour les blocs d'alimentation à
découpage et les transformateurs pour blocs d'alimentation à découpage pour
applications d'ordre général
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IEC 61558-2-16 ®
Edition 2.0 2021-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Safety of transformers, reactors, power supply units and combinations thereof –

Part 2-16: Particular requirements and tests for switch mode power supply units

and transformers for switch mode power supply units for general applications

Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et

combinaisons de ces éléments –

Partie 2-16: Exigences particulières et essais pour les blocs d'alimentation à

découpage et les transformateurs pour blocs d'alimentation à découpage pour

applications d'ordre général
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.180 ISBN 978-2-8322-9855-8

– 2 – IEC 61558-2-16:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 10
3 Terms and definitions . 10
4 General requirements . 11
5 General notes on tests . 12
6 Ratings . 12
7 Classification . 12
8 Marking and other information . 12
9 Protection against electric shock . 14
10 Change of input voltage setting . 14
11 Output voltage and output current under load . 15
12 No-load output voltage . 15
13 Short-circuit voltage . 16
14 Heating . 16
15 Short-circuit and overload protection . 17
16 Mechanical strength . 17
17 Protection against harmful ingress of dust, solid objects and moisture . 17
18 Insulation resistance, dielectric strength and leakage current . 17
19 Construction . 17
20 Components . 18
21 Internal wiring . 18
22 Supply connection and other external flexible cable or cords . 18
23 Terminals for external conductors . 18
24 Provisions for protective earthing. 18
25 Screws and connections . 18
26 Creepage distances, clearances and distances through insulation . 18
27 Resistance to heat, fire and tracking . 32
28 Resistance to rusting . 32
Annexes . 33
Annex AA (normative) Partial discharge (PD) test . 34
Annex BB (normative) Particular requirements for associated transformers for use in
switch mode power supply units with internal frequencies > 500 Hz . 35
Annex CC (informative) Example for determination of clearances and creepage
distances for associated transformers for use in switch mode power supply units . 38
Bibliography . 40

Figure 101 – Diagram for dimensioning of clearances . 19
Figure 102 – Diagram of dimensioning creepage distances . 24
Figure 103 – Permissible electric field strength for dimensioning of solid insulation in
accordance with Formula (2) . 32

Table 101 – Symbols used on SMPS . 13
Table 102 – Output voltage ratio . 16
Table 103 – Rated impulse voltage . 20
Table 104 – Clearances to withstand transient overvoltages for inhomogeneous field . 21
Table 105 – Values of clearances for peak working voltages produced in the SMPS for
frequencies ≤ 30 kHz . 22
Table 106 – Minimum values of clearances in air for inhomogeneous electric field
conditions for frequency > 30 kHz . 23
Table 107 – Basic or supplementary insulation – Minimum values of creepage
distances for different frequency ranges (pollution degree 1) . 25
Table 108 – Basic or supplementary insulation – Minimum values of creepage
distances for different frequency ranges (pollution degree 2) . 26
Table 109 – Basic or supplementary insulation – Minimum values of creepage
distances for different frequency ranges (pollution degree 3) . 27
Table 110 – Double or reinforced insulation – Minimum values of creepage distances
for different frequency ranges (pollution degree 1) . 28
Table 111 – Double or reinforced insulation – Minimum values of creepage distances
for different frequency ranges (pollution degree 2) . 29
Table 112 – Double or reinforced insulation – Minimum values of creepage distances
for different frequency ranges (pollution degree 3) . 30
Table CC.1 – Conditions . 38

– 4 – IEC 61558-2-16:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF TRANSFORMERS, REACTORS, POWER SUPPLY
UNITS AND COMBINATIONS THEREOF –

Part 2-16: Particular requirements and tests for switch mode power
supply units and transformers for switch mode power supply units
for general applications
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,
...