The thesis project entitled "Surge 1.2/50 µs test automation for DIN-Rail Residual Current CB", carried out at the ABB S.p.A company based in Vittuone (MI), starting from the study of residual current circuit breakers was the protagonist of the development of the automation of a test carried out daily within the laboratory that deals with the electromagnetic compatibility verification of products. The task of the surge test is to verify that the devices are sufficiently immune to such disturbances by meeting the functional and safety requirements of the relevant product standards. Residual current circuit breakers during the test may trip as a result of applied over-voltages.