Fuse holder for 24kV cut cut fuse

Fuse holder for 24kV cut cut fuse

In the utilities industry, a fuse cutout is a combination of a fuse and a switch. These units are used primarily on overhead feeder lines and are designed to protect distribution transformers from any current spikes or surges that can overload equipment. 

What are the major components of a fuse cutout: 

Body: The frame which supports the fuse tub/blade and is mounted to the crossarm or bracket. 

Fuse Holder: Known as the fuse tube or "door" that contains the fuse link. 

Fuse Link: Also known as an element, is the replaceable portion of the product that extinguishes due to higher than normal current transfers.

How does a fuse cutout work? 

A current surge from a customer circuit or a transformer will cause the fuse inside the tube to expand and melt. Once the fuse reaches maximum current capacity it breaks and this energy is thrown out of the bottom of the tube and disconnects the transformer from the line by the tube dropping out of the upper contact and swinging down on the hinge. The physical indication that the fuse has been extinguished and needs to be replaced is seen when the tube swings open and remains in a downward orientation.