Deciding on where to place a back-up transformer is not an easy task. It involves factors that might be considered irrelevant or of little influence, but which in fact are extremely important and ensure the success of the location process. This procedure requires close attention to key criteria as well as careful planning and lengthy, widely-ranging studies of placement alternatives before definitively choosing where the back-up transformer should be placed. This study contributes a multi-criteria perspective on the question, by proposing a methodology which takes the key criteria into full consideration when determining the best location for a back-up transformer. These include considerations of public health, the spread and location of local industries, and the population of the area, as well as drawing up an index of the distance of the back-up transformer from the population which is usually deemed as a transport cost. When these criteria are taken into consideration, the best location is that which generates the least loss in maximizing the total utility. This can be interpreted as the judgment made regarding the location of the back-up in a substation,  taking into consideration the benefits of the back-up being in this place.