Dropout Fuse Cutout

Dropout fuse cutout is an outdoor protective device used on distribution lines, mainly for overload and short-circuit protection. It is also used for line sectionalizing, equipment isolation, and transformer protection.
Common voltage ratings include 11kV, 15kV, 27kV, and 33kV dropout fuse cutouts.

The main components of a dropout fuse cutout (fuse cutout assembly) are:
• Insulating support (porcelain or polymer insulator)
• Fuse tube
• Fuse link
• Conductive parts (copper or tinned copper components).

Dropout fuse cutout working principle:
Under normal operating conditions, the fuse link inside the cutout carries the load current, and the fuse tube remains firmly engaged with the upper and lower contacts to keep the circuit energized.

When a short-circuit or severe overload occurs, the high fault current rapidly melts the fuse link. Once the fuse link breaks, the fuse tube loses its holding tension. Driven by its own weight and the release of the contact springs, the fuse tube drops open, creating a clear visible break and safely isolating the faulted section of the line.