CSA Preface
This is the third edition of CSA IEC 61558-2-6, Safety of transformers, reactors, power supply units and combinations thereof — Part 2-6: Particular requirements and tests for safety isolating transformers and power supply units incorporating safety isolating transformers for general applications, which is an adoption without modification of the identically titled IEC (International Electrotechnical Commission) Standard 61558-2-6 (third edition, 2021-05). It supersedes the previous edition, published in 2020 as CSA IEC 61558-2-6 (adopted IEC 61558-2-6:2009), Safety of transformers, reactors, power supply units and similar products for supply voltages up to 1 100 V — Part 2-6: Particular requirements and tests for safety isolating transformers and power supply units incorporating safety isolating transformers.
For brevity, this Standard will be referred to as CSA IEC 61558-2-6 throughout.
This Standard is intended to be used in conjunction with CAN/CSA-E61558-1:12, Safety of power transformers, power supplies, reactors and similar products — Part 1: General requirements and tests (adopted IEC 61558-1:2005+A1:2009, with Canadian deviations).
This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard.
The Standard was reviewed for Canadian adoption by the CSA Technical Committee on International Standards, under the jurisdiction of the CSA Strategic Steering Committee on Requirements for Electrical Safety, and has been formally approved by the Technical Committee.
This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group.
Scope
Replacement
This part of IEC 61558 deals with the safety of safety isolating transformers for general applications and power supply units incorporating safety isolating transformers for general applications. Transformers incorporating electronic circuits are also covered by this document.
NOTE 1 Safety includes electrical, thermal and mechanical aspects.
Unless otherwise specified, from here onward, the term transformer covers safety isolating transformers for general applications and power supply units incorporating safety isolating transformers for general applications.
For power supply units (linear) this document is applicable. For switch mode power supply units IEC 61558-2-16 is applicable.
This document is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural or forced) independent or associated dry- type transformers. The windings can be encapsulated or non-encapsulated.
The rated supply voltage does not exceed 1 000 V AC and the rated supply frequency and the internal operating frequencies do not exceed 500 Hz.
The rated output does not exceed:
• 10 kVA for single-phase transformers;
• 16 kVA for polyphase transformers.
This document is applicable to transformers without limitation of the rated output subject to an agreement between the purchaser and the manufacturer.
NOTE 2 Transformers intended to supply distribution networks are not included in the scope.
The no-load output voltage or the rated output voltage does not exceed 50 V AC or 120 V ripple-free DC.
This document is not applicable to external circuits and their components intended to be connected to the input terminals and output terminals of the transformers.
NOTE 3 Transformers covered by this document are used in applications where double or reinforced insulation between circuits is required by the installation rules or by the end product standard.
Attention is drawn to the following:
• additional requirements for transformers intended to be used in vehicles, on board ships, and aircraft (from other applicable standards, national rules, etc.);
• measures to protect the enclosure and the components inside the enclosure against external influences such as fungus, vermin, termites, solar-radiation and icing;
• the different conditions for transportation, storage, and operation of the transformers;
• additional requirements in accordance with other appropriate standards and national rules can be applicable to transformers intended for use in special environments.
Future technological development of transformers can necessitate a need to increase the upper limit of the frequencies. Until then, this document may be used as a guidance document.
This group safety publication focusing on safety guidance is primarily intended to be used as a product safety standard for the products mentioned in the scope, but is also intended to be used by TCs in the preparation of publications for products similar to those mentioned in the scope of this group safety publication, in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51.
One of the responsibilities of a TC is, wherever applicable, to make use of BSPs and/or GSPs in the preparation of its publications.