This article presents the development of an automatism by means of a Programmable Logic Controller (PLC), for the Fire System of an Electric Substation; For this, the areas belonging to the electrical substation are initially described, where the automatism is developed, these being three; Patio area (Transformer location), Distribution board area and Control room. Then the components to be used in the automatism are identified, which are; 16 sensors (input elements), as well as 5 solenoid valves, 3 electro-pumps and 3 frequency inverters (output elements). Then the programming of the S71200 PLC is developed, through the contact scheme language, the automatic control guarantees the optimal operation of the system components. Once the system has been developed, the Cronbach Alpha test is carried out in the statistical program SPSS (Startical Product and Service Solutions), which determines that the reliability is 0.794. Finally, the normality of the data was verified through the Shapiro Wilk test, obtaining as a result a significance of 0.60 for the pressure and 0.166 for the flow rate; being these data greater than the level of significance α = 0.05, we can conclude that the variable pressure and flow follow a normal distribution, which is reflected in the normal QQ graph, in this way the correct operation of the fire system would be guaranteed. of the Electrical Substation..