This invention pertains to a simple, economical, reliable secure operation mechanism that can be adapted to factory production, or for post-sale, on any electrical shutdown device in a cabinet, that is designed to enable the shutdown device to be switched, while the cabinet is open, only after an additional voluntary action is performed by the operator on a secondary handle provided inside said cabinet.The shutdown device (1) is characterized in that it has a secure operation mechanism (10) equipped with a secondary handle (11) attached to the control shaft (6) that is accessible from inside the cabinet (4), a return mechanism (13) that moves the control shaft (6) toward the door (5), a padlocking plate (14) lengthened by a stub (15) that is mounted on the control shaft (6) under the secondary handle (11) and a plate (17) connected to one lateral surface of the shutdown device (1) that has an opening (18) througch which the stub (15) passes, and that defines a lock zone (18a) preventing the shutdown device (1) from switching, and an unlock zone (18b) that enables this switching.