IEC TS 62257-2:2015(E) proposes a methodological approach for the setting up and carrying out of socio-economic studies as part of the framework of decentralized rural electrification projects. It is addressed to project teams and in particular to experts in charge of socio-economic studies in international projects. This technical specification also provides some structures as technical solutions that could be recommended, depending on the qualitative and quantitative energy demands, consistent with the needs and financial situation of the customers. The main technical changes with regard to the previous edition are as follows: - redefine the maximum AC voltage from 500 V to 1 000 V, the maximum DC voltage from 750 V to 1 500 V; - removal of the limitation of 100 kVA system size. This publication is to be read in conjunction with IEC 62257 series