Electricity system consists of generation, transmission & distribution networks. The transmission & distribution loss and commercial losses play an important role in determining the cost of energy utilized by the user. The generation capacity, transmission, and distribution capacity depends on the losses & demand. When the loss is more, the generation capacity, transmission, and distribution capacity are to be increased. The main aim of SEBs is to give the electricity at cheaper cost, so it is necessary to minimize the Aggregate Technical And Commercial (ATC) Losses. But so far, no attempt is made to accurately calculate the losses by the SEBs. A test feeder is taken to analyze the ATC losses. In the analysis, distribution transformers (DT) loading, Power factor, Regulation and energy meter working conditions are studied. The aim of the analysis is to assess the present ATC losses in secondary distribution system on a selected feeder. This work suggests improvement measures to reduce the ATC losses within the permissible value and implement some of our suggestions and then determine the new ATC losses. After corrective measures are taken, the ATC losses are found reduced