SR EN IEC 61558-2-4:2025

Replacement This part of IEC 61558 deals with the safety of isolating transformers for general applications and power supply units incorporating isolating transformers for general applications. Transformers incorporating electronic circuits are also covered by this document. NOTE 1 Safety includes electrical, thermal and mechanical aspects. Unless otherwise specified, from here onward, the term transformer covers isolating transformers for general applications and power supply units incorporating isolating transformers for general applications. For power supply units (linear) this document is applicable. For switch mode power supply units, IEC 61558-2-16 is applicable. This document is applicable to stationary or portable, single-phase or polyphase, air-cooled (natural or forced) independent or associated dry- type transformers. The windings can be encapsulated or non-encapsulated. The rated supply voltage does not exceed 1 000 V AC and the rated supply frequency and the internal operating frequencies do not exceed 500 Hz. The rated output does not exceed: - 25 kVA for single-phase t