Overload capacity depends on hot-spot temperature limits, insulation class, prior loading history, ambient temperature, and cooling capability. Manufacturers provide thermal models and overload curves based on IEC/IEEE guidelines. If the transformer starts cool and ambient is low, it can carry higher current for limited periods without exceeding allowable hot-spot temperatures. Repeated or prolonged overloads, however, accelerate insulation aging and may reduce life expectancy. Oil circulation and radiator design strongly influence how safely overloads can be handled.