This being the most vital part in the manufacture of transformers mechanical rigidity, electrical performances and future service life being dependent upon the quality of Winding Assembly, strict adherence to pre- set assembly parameters is thoroughly maintained. The upper and lower Insulation Barriers, Vertical and Axial spacer blocks, oil ducts etc. are fabricated with Pressboard, Permawood, Ceramic blocks, Fiver Boards, Fiver Glass and other Electrical Grade Insulation Materials are selected depending upon Insulation Class of a particular item under production. All electrical and mechanical clearances in assembly are meticulously maintained as per drawing. All insulation blocks are preheated clearances in assembly are meticulously maintained as per drawing. All insulating blocks are preheated before use in assembly to reduce shrinkage in service. Assembly parameters are selected to keep out-of – balance forces to a minimum which ensures short – circuit withstand capacity of transformers.