Shell for a rotating electrical machine, the shell comprising a first shell part and a second shell part, wherein: the first shell part and the second shell part are coupled to form a cavity which receives at least a shaft, a rotor and stator; the first shell part is formed in a single piece, the first shell part having a cylindrical wall section and an end section with a shaft passage hole; the second shell part is formed in a single piece, the second shell part having a cylindrical wall section an end section with a shaft passage hole; the cavity is configured to receive the stator in radial contact with an inner surface of the shell; the internal surfaces of the first and second shell parts (10, 13) are free of elements limiting the displacement of the stator in the axial direction; the cylindrical wall section of the first shell part comprises, all formed in a single piece, at least one terminal box receiving portion (11 b), at least two connection elements receiving portions and at least two tubular elements (11 d) integrally formed in the first shell part, each tubular element having an internal threaded channel for receiving a fastening element; the cylindrical wall section of second shell part comprises, formed in a single piece, at least two coupling elements, each coupling element having a through central hole for receiving a fastening element; and the tubular elements and the coupling elements are configured to coincide when the shell parts are coupled, so that each respective fastening element can be inserted through the through central hole of each respective coupling element and threaded to the internal channel of each respective tubular element (11 d). the first shell part and the second shell part are coupled to form a cavity which receives at least a shaft, a rotor and stator; the first shell part is formed in a single piece, the first shell part having a cylindrical wall section and an end section with a shaft passage hole; the second shell part is formed in a single piece, the second shell part having a cylindrical wall section an end section with a shaft passage hole; the cavity is configured to receive the stator in radial contact with an inner surface of the shell; the internal surfaces of the first and second shell parts (10, 13) are free of elements limiting the displacement of the stator in the axial direction; the cylindrical wall section of the first shell part comprises, all formed in a single piece, at least one terminal box receiving portion (11 b), at least two connection elements receiving portions and at least two tubular elements (11 d) integrally formed in the first shell part, each tubular element having an internal threaded channel for receiving a fastening element; the cylindrical wall section of second shell part comprises, formed in a single piece, at least two coupling elements, each coupling element having a through central hole for receiving a fastening element; and the tubular elements and the coupling elements are configured to coincide when the shell parts are coupled, so that each respective fastening element can be inserted through the through central hole of each respective coupling element and threaded to the internal channel of each respective tubular element (11 d).