A core for a three-phase transformer is disclosed. The core includes: first, second and third core segments joined together to define three lengthwise extending core legs and first and second core ends disposed generally perpendicularly to the core legs. The core ends are arranged to define a Y shape. Each core segment is formed by nesting together a plurality of magnetic steel strip laminations,the laminations having end sections. The end sections of the laminations overlap such that the ratio of the thickness of the first core end to the thicknesses of the leg thickness is greater that 1:1and less than 2:1. In one form the ratio of the thickness of the first end to the thicknesses of the leg thickness is 3:2.