Safety of power transformers, power supplies, reactors and similar products - Part 1: General requirements and tests

This International Standard deals with safety aspects of power transformers, power supplies, reactors and similar products such as electrical, thermal and mechanical safety.

This standard covers the following types of dry-type transformers, power supplies, including switch mode power supplies, and reactors, the windings of which may be encapsulated or non-encapsulated :

a) Stationary or portable, single-phase or poly-phase, air-cooled (natural or forced), isolating and safety isolating transformers, independent or associated, not forming a part of distribution networks and with the following characteristics:

- rated supply voltage not exceeding 1 000 V a.c.;

• - rated supply frequency not exceeding 500 Hz;
  
  and complying with the following values, unless otherwise specified in the relevant part 2:
  
  * for isolating transformers:
  
  - rated output for single phase transformers, not exceeding 25 kVA, and for polyphase transformers not exceeding 40 kVA.
  
  - no-load output voltage and the rated output voltage exceeding 50 V a.c., and not exceeding 500 V a.c, or 1 000 V a.c. to be in accordance with the National Wiring Rules or for a special application.
  
  * for safety isolating transformers:
  
  - rated output for single phase transformers not exceeding 10 kVA, and for polyphase transformers not exceeding 16 kVA.
  
  - no-load output voltage and the rated output voltage not exceeding 50 V a.c.
  
  between conductors, or between any conductor and protective earth.
• b) Stationary or portable, single-phase or polyphase, air-cooled (natural or forced) separating transformers, auto-transformers, variable transformers and small reactors, independent or associated, not forming a part of distribution networks and with the following characteristics:
• - rated supply voltage not exceeding 1 000 V a.c.;
  
  - rated supply frequency not exceeding 500 Hz;
  
  and complying with the following values, unless otherwise specified in the relevant part 2:
  
  - no-load output voltage or a rated output voltage for both independent and associated transformers not exceeding 15 kV a.c., and for independent transformers, a rated output voltage not less than 50 V a.c.;
  
  - rated output not exceeding the following values:
  
  - 1 kVA for single-phase transformers;
  
  - 2 kVAR for single-phase reactors;
  
  - 5 kVA for poly-phase transformers;
  
  - 10 kVAR for poly-phase reactors.