IEC 61558-1:2017

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 General notes on tests
6 Ratings
7 Classification
8 Marking and other information
9 Protection against electric shock
10 Change of input voltage setting
11 Output voltage and output current under load
12 No-load output voltage
13 Short-circuit voltage
14 Heating
15 Short circuit and overload protection
16 Mechanical strength
17 Protection against harmful ingress of dust, solid
   objects and moisture
18 Insulation resistance, dielectric strength and leakage
   current
19 Construction
20 Components
21 Internal wiring
22 Supply connection and other external flexible cables
   or cords
23 Terminals for external conductors
24 Provisions for protective earthing
25 Screws and connections
26 Creepage distances, clearances and distances through
   insulation
27 Resistance to heat, fire and tracking
28 Resistance to rusting
Annex A (normative) - Measurement of creepage distances
        and clearances
Annex B (normative) - Testing a series of transformers
Annex C - (void)
Annex D - (void)
Annex E (normative) - Glow-wire test
Annex F (normative) - Requirements for manually
        operated switches which are parts of transformers
        assembly
Annex G (normative) - Tracking test
Annex H (normative) - Electronic circuits
Annex I (informative) - Dimensions for rectangular
        cross-section connectors of transformers, basic
        dimensions and coordination
Annex J (normative) - Measuring network for touch-currents
Annex K (normative) - Insulated winding wires
Annex L (normative) - Routine tests (production tests)
Annex M (informative) - Examples to be used as a guide
        for 19.1
Annex N (informative) - Examples for checking points
        of dielectric strength test voltages
Annex O - (void)
Annex P (informative) - Examples for measurement
        points of creepage distances and clearances
Annex Q (informative) - Explanation of IP numbers for
        degrees of protection
Annex R (normative) - Explanations of the application
        of 6.1.2.2.1 of IEC 60664-1:2007
Annex S - (void)
Annex T - (void)
Annex U - (void)
Annex V (informative) - Symbols to be used for thermal
        cut-outs
Annex W (normative) - Coated printed circuit boards
Bibliography
Index of defined terms

IEC 61558-1:2017 deals with safety aspects of transformers, reactors, power supply units and combinations thereof such as electrical, thermal and mechanical safety. This document covers the following independent or associated stationary or portable types of dry-type transformers, power supply units, including switch mode power supply units, reactors and combinations thereof in the field of safety. The windings can be encapsulated or non-encapsulated. They are not forming a part of the distribution network. This third edition cancels and replaces the second edition published in 2005 and Amendment 1:2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a. fully insulated winding wires (FIW), new tables and aging tests for FIW constructions,
b. overvoltage categories 1, 2, 3 and 4 for clearances and dielectric strength tests (new tables) are included,
c. development of new symbols for the different overvoltage categories,
d. symbol for maximum altitudes, if higher than 2 000 m,
e. symbol for plug in power supply units, if the pins are damaged (tumbling barrel test),
f. symbol for minimum temperature (even during the transportation),
g. alternative temperature measurement, simulated load and back to back method according to IEC 60076-11,
h. short circuit and overload protection, simulated load and back to back method according to IEC 60076-11,
i. adjustment of temperatures in Table 2 according to CENELEC Guide 29,
j. establishing partial discharge test above 750 V for FIW constructions,
k. requirements for toroidal core constructions, division for basic and for supplementary isolation,
l. modification of protection indexes for enclosures (IP-code),
m. dimensioning of rectangular cross section connectors for transformers,
n. repetition test, 80% of required dielectric strength test voltage of Table 14,a.
o. vibration test for vehicles and railway applications,
p. two Y1 Capacitors for working voltages above 250 V and not exceeding 500 V with overvoltage category 3.
It has the status of a group safety publication in accordance with IEC Guide 104.