Protective switch devices such as relay switches comprise, for each pole, a contact bridge able to be displaced in relation to the stationary contacts. In case of an electrical failure on at least one of the poles, a magnetic and/or thermal trip mechanism is able to cause an opening of the contacts. This trip mechanism acts on a control mechanism referred to as a lock. Furthermore, this control mechanism can be activated manually by a manual control knob so as to displace the moving contacts in relation to the stationary contacts by a switch controlling the electromagnet.

The characterized by the fact that the control mechanism comprises a lever for opening the contacts that pivots from an on position corresponding to the closing of the contacts to a position corresponding to the opening of the contacts, this opening lever being associated with a pivoting cocking mechanism, able to bring back and hold said opening lever in the "on" position of the contacts, and by the fact that the trip means are able to control the mechanical separation of the opening lever and of the cocking mechanism so as to free this opening lever.