The precocious success in Milan electrical technology, since the dawn of the second industrial revolution, is closely tied to the attention paid to it in the technical and scientific environment of the Politecnico. Thanks to the primogeniture in the field of electric lighting (1883) and of the electric tram traction (1892), according to the newly-established American technologies, Milan quickly became the capital of the Italian electricity industry, so that in 1914 already (before the post-war period) 20% of the Italian electro-commercial companies were based in the Lombard capital (and they owned 36% of the total capital). This picture was completed by the presence of the most important electrotechnical companies and of the greater public electricity company: Aem. The successes of the electrical entrepreneurship in Milan would have been the source of significant positive effects on the Politecnico, starting a special and symbiotic relationship between the development of the Italian electricity sector and the Milan training Institution. A symbiotic "privileged" relationship both when it started a virtuous circle between research in the field of electrical engineering and hydraulics and implementation of hydroelectric plants and transmission lines, and also with negative connotations when one considers that the pervasiveness of the hydroelectric paradigm was the cause of distorted trends or omissions, such as a less attention paid to other forms of energy.
Keywords: Milan, Politecnico, Electrical Industry, Giuseppe Colombo, Carlo Erba, Giacinto Motta.