A clamp for a male terminal having features for preventing incorrect clamping, which comprises a main body having a ring and two jaws, that are movable toward each other for the ring to hold the terminal. An engagement element is movable in the vertical direction and to act upon the jaws to move them toward each other. A clamping member, operable to move the engagement element comprises a stem and a nut. The stem is fixed to a base body, which is pivotable relative to the main body between a first position, in which the stem is inclined with respect to the vertical and a second position, in which the stem extends in the vertical direction. In the first position, the engagement element prevents the nut from engaging a threaded portion of the stem. In the second position, the threaded portion is adapted to be engaged by the nut.