This part of IEC 61558 applies to stationary or portable, single-phase or poly-phase, air-cooled (natural or forced) general purpose small reactors, including alternating current, premagnetised and current compensated reactors, independent or associated, having a rated supply voltage not exceeding 1000 V a.c. or d.c. and rated frequency not exceeding 1 MHz, the rated power not exceeding - 2 kVAR a.c. (2 kW d.c.) for single-phase reactors; - 10 kVAR a.c. (10 kW d.c.) for poly-phase reactors. This part 2-20 is intended to be used in conjunction with IEC 61558-1. It has the status of a group safety publication in accordance with IEC Guide 104.