Abstract: An integrated fuse device (1) includes a varistor stack (11), a thermal fuse (12), and a current fuse (13) within an enclosure (2) having device terminals (3). The varistor stack (11) is connected to the thermal fuse (12) by a Cu terminal (20) and is connected to the device terminal (3) by steel terminal (10) of smaller cross-sectional area. Being of Cu material and having a greater cross-sectional area, the terminal (20) connected to the thermal fuse (12) has greater thermal conductivity than the steel terminal (10) to the end cap (3). The thermal fuse (12) comprises a plurality of links having a melting point to melt with sustained overvoltage, the links having a diameter in the range of about 2 mm to about 3 mm. The links pass through an elastomer plug (15), which exerts physical pressure on them to assist with opening during sustained overvoltage. Hot melt (18) around solder (17) of the thermal fuse limits heat conduction to back-fill sand.

Abstract: An integrated fuse device (1) includes a varistor stack (11), a thermal fuse (12), and a current fuse (13) within an enclosure (2) having device terminals (3). The varistor stack (11) is connected to the thermal fuse (12) by a Cu terminal (20) and is connected to the device terminal (3) by steel terminal (10) of smaller cross-sectional area. Being of Cu material and having a greater cross-sectional area, the terminal (20) connected to the thermal fuse (12) has greater thermal conductivity than the steel terminal (10) to the end cap (3). The thermal fuse (12) comprises a plurality of links having a melting point to melt with sustained overvoltage, the links having a diameter in the range of about 2 mm to about 3 mm. The links pass through an elastomer plug (15), which exerts physical pressure on them to assist with opening during sustained overvoltage. Hot melt (18) around solder (17) of the thermal fuse limits heat conduction to back-fill sand.