This part 2 of IEC 61558 applies to stationary or portable, single-phase or polyphase, air-cooled safety isolating transformers, associated or othervvise, having a rated supply voltage not exceeding 1000 V a.c. and rated frequency not exceeding 500 Hz, the rated output not exceeding:
- 10 kVA for single-phase transformers;
- 16 kVA for polyphase transformers.
This standard is also applicable to safety isolating transformers vvithout limitation of the rated output; hovvever such transformers are considered as special transformers and are subjected to an agreement betvveen the purchaser and the supplier.