The design process considers service voltage, system fault levels, loading profile, efficiency targets, noise limits, and lifecycle cost. Engineers choose core materials, insulation systems, winding configurations, and cooling types to meet performance goals while complying with standards. Mechanical design must withstand short-circuit forces and shipping stresses. Accessories like OLTCs, bushings, and monitoring devices are selected based on application. Environmental constraints, including footprint, transportation limits, and required environmental performance (leak containment, fire safety), also influence the final design.