During a short circuit, the transformer's inner winding, which is supported by the inner support structure, may fail due to the buckling phenomenon. This occurs due to the generation of large radially inward electromagnetic force on the inner winding. In the literature, the effect of the number of axial supporting spacers on the critical buckling stress is reported, but there is no investigation about the effect of their circumferential width on the value of the critical buckling stress. In this letter, the effect of the circumferential width of the axial supporting spacers on the value of critical buckling stress of the transformer inner winding has been investigated. An algorithm has been given to calculate the critical buckling stress of the inner winding. A case study has been taken from the published work, and by varying the width of the spacers, the factor of safety against buckling has been determined. © 1986-2012 IEEE.