KS IEC61558-2-4:2009

Specification for safety of power transformers, power supply units and similar apparatus - Part 2-4: Particular requirements for isolating transformers for general use.

Applies to stationary or portable, single-phase or poly-phases, air-cooled control transformers associated or otherwise having a rated supply voltage not exceeding 1000 V a.c., and a rated frequency not exceeding 500 Hz, the rated output not exceedin