This Standard applies -tap stationary or portable, single phase or three phase transformers intended generally fdr the supply of a single electrical appliance and for a complete electrical separation between mains voltage and the voltage appearing on the output, where the supply voltage of the transformers does not exceed 250volts to ground and their rated output does not exceed 2500 VA for single phase transformers or 6300 VA for three phase transformers.
The requirements pf this Standard apply also ta isolating transformers whose output exceeds the above-mefijtioned"limits aftd also to isolating transformers intended for use in locations flhere an explosion or fire danger exists, or intended for use; in locations where there is a considerable amount of dust and also to isolating transformers whose rated voltage exceeds 250 volts; however, the compliance of the; transformers with the requirements of this Standard does not constitute a proof of;their fitness for use in these locations, unless they comply with requirements, others or additional, which are not included in this Standard.