Detector of at least one electric parameter in an electrical conductor, the detector comprising a frame on which there is mounted a mechanism which includes: - a magnetic core divided into first and second arms (16, 18), the core having a coil wound around one of its arms; and - at least two jaws for anchoring the detector on the electrical conductor, each jaw being movable in rotation, about an axis defined by the frame, between an open position and a locked position of the jaw; the detector being such that: - the first arm of the core is integral with the frame and its second arm is movable, in rotation about an axis parallel to the axis of rotation of at least one jaw and defined by the frame, relative to the first arm, between an open position, in which the second arm is spaced apart from the first arm, a pre-closure position, in which the second arm is closer to the first arm, and a closed position of the magnetic core, in which the first and second arms (16, 18) are closed on one another, - the mechanism also comprises a support member which is integral with the second arm of the magnetic core and defines at least one concave volume (V1, V2) for receiving part of the electrical conductor, the support member being capable of transmitting to the second arm of the magnetic core a torque of pre-closure of the magnetic core towards a pre-closure position, wherein the electrical conductor is in place in the support member and the support member is suspended from the second arm; - the jaws are configured to apply to the electrical conductor a clamping force when it is in place in the support member; and - the support member is capable of transmitting to the second arm the clamping force exerted by the jaws on the electrical conductor and of displacing that arm from the pre-closure position towards the closed position, - the first and second arm (16, 18) are arranged in first and second casings (20, 22), respectively, and the support member is mounted on the second casing, wherein the support member is composed of a bent wire which defines two parallel portions (30, 32) each having a free end arranged in a bore of a lug of the second casing. - a magnetic core divided into first and second arms (16, 18), the core having a coil wound around one of its arms; and - at least two jaws for anchoring the detector on the electrical conductor, each jaw being movable in rotation, about an axis defined by the frame, between an open position and a locked position of the jaw; - the first arm of the core is integral with the frame and its second arm is movable, in rotation about an axis parallel to the axis of rotation of at least one jaw and defined by the frame, relative to the first arm, between an open position, in which the second arm is spaced apart from the first arm, a pre-closure position, in which the second arm is closer to the first arm, and a closed position of the magnetic core, in which the first and second arms (16, 18) are closed on one another, - the mechanism also comprises a support member which is integral with the second arm of the magnetic core and defines at least one concave volume (V1, V2) for receiving part of the electrical conductor, the support member being capable of transmitting to the second arm of the magnetic core a torque of pre-closure of the magnetic core towards a pre-closure position, wherein the electrical conductor is in place in the support member and the support member is suspended from the second arm; - the jaws are configured to apply to the electrical conductor a clamping force when it is in place in the support member; and - the support member is capable of transmitting to the second arm the clamping force exerted by the jaws on the electrical conductor and of displacing that arm from the pre-closure position towards the closed position, - the first and second arm (16, 18) are arranged in first and second casings (20, 22), respectively, and the support member is mounted on the second casing,