The device has an insulator (3) exerting an elastic force on a fuse, where the fuse secures an electrical connection between connection studs (11, 12) in its operational configuration and breaks the connection in its final breaking configuration under the effect of a temperature rise and the force. The insulator has two wings respectively adjacent to the studs and with front edges supported on the fuse in the operational configuration, where the ends of the fuse are mechanically maintained by the respective studs against a traction force along a direction in which the studs are aligned. An independent claim is also included for a lightning arrestor using this protection device.