Abstract: A measurement and protection transformer for high, medium and low voltages, of the type having a magnetic core, together with primary and secondary windings. All these elements are exteriorly molded with resin, forming a single, exterior resin body to obtain a transformer design with all the guarantees of safety and durability, especially under extremely humid environmental conditions. The transformer is for high, medium and low voltages that has a magnetic core, together with primary and secondary windings and transformer primary and secondary connections, with the particularity in which all these elements are molded and completely embedded within a mass of resin that forms the outer body or single-piece casing of the transformer.