EN 61558-2-4:2009

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 cable
   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
Annexes
Annex C - Creepage distances (cr), clearances (cl) and
          distances through insulation (dti) Material
          group II (400 <= CTI < 600)
Annex D - Creepage distances (cr), clearances (cl) and
          distances through insulation (dti) Material
          group I (CTI >= 600)
Annex R - Explanations of the application of 4.2 of IEC
          60664-1:2007
Bibliography
Annex ZA (normative) - Normative references to international
                       publications with their corresponding
                       European publications

IEC 61558-2-4:2009 deals with the safety of isolating transformers for general applications and power supply units incorporating isolating transformers for general applications. Transformers incorporating electronic circuits are also covered by this standard. This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this part in accordance with Part 1 (2005), and increasing the supply voltages up to 1 100 V to be in line with the standards of TC 14. This part has the status of a group safety publication in accordance with IEC Guide 104. This part is intended to be used in conjunction with the latest edition of IEC 61558-1 and its amendments. It is based on the second edition (2005) of that standard. It is the recommendation of the committee that the content of this publication be adopted for implementation nationally not earlier than 12 months from the date of publication.