Fusible link

A mechanical fusible link is a device consisting of two strips of metal soldered together with a fusible alloy that is designed to melt at a specific temperature, thus allowing the two pieces to separate.

Fire dampers in ventilation systems have fusible links so that the dampers close automatically in case of fire, limiting the spread of flame or hot gases through a building.

[1] Some high-security safes also utilize fusible link-based relockers as a defense against torches and heat-producing tools.

Mechanical fusible links come in a variety of designs and different temperature ratings.

Electrical fusible links are common in high-current automotive applications.