This document shows an analysis of the voltage profiles, which are an indicator of the reliability of an electrical system, since the network behaves by implementing the charging of electric vehicles (YE) in a typical residential demand curve. Depending on several charging scenarios of electric vehicles, it is possible to determine if the current network of the distribution company has the necessary infrastructure to be able to supply the load of electric vehicles and residential demand. This analysis is done through the Monte Carlo algorithm using Markov chains, which allows us to obtain an optimal and reliable result of this study thanks to the probabilities of the Markov chains. The analysis is associated to the prediction of the maximum power required to satisfy the peak demand period in the distribution systems with a predominance of residential load, also looking for the planning of the networks to increase the efficiency, quality and reliability of the energy supply in peak hours.