This Standard is an adoption with national modifications of the second edition of IEC 61558-2-23, Safety of Power Transformers, Power Supplies, Reactors and combinations thereof - Part 2-23: Particular requirements for transformers and power supply units for construction sites. This part 2 has to be used in conjunction with the latest edition of AS/NZS 61558.1 Safety of Power Transformers, Power Supplies, Reactors and Similar Products - Part 1: General requirements and tests and its amendments. It was established on the basis of the 2008 edition of that standard. Amendments and revisions of Part 1 have also to be taken into account and the dates when such changes become applicable will be stated in the relevant amendment or revision of Part 1. The main changes consist of updating this part in accordance with AS/NZS 61558.1:2008. The national variations to the IEC 61558-2-23 Ed 2 form the Australian and New Zealand national variations for purposes of the IECEE scheme for recognition of results of testing to standards for safety of electrical equipment (the CB scheme).