The invention relates to an actuating device (1) for an electrical switch device comprising a body (10) upon which is mounted a hand lever (2) that rotates about a main axis (A), cooperating with a transmission shaft (3) able to control the opening or the closing of electrical contacts of the electrical switch device and elastic linking means between the hand lever (2) and the transmission shaft (3). The device also comprises means (7) for locking the rotation of the hand lever (2) with respect to the body (10), used when an angular divergence between the hand lever (2) and the transmission shaft (3) exceeds a specified threshold. The purpose of the invention is to limit the damage to the hand lever and to the electrical device when an operator attempts to return the hand lever (2) to its “Off” position whilst the contacts are welded and to prevent the beginning of electrical arcing if the operator should succeed in unsticking the contacts when rotating the hand lever 2.