Drop Out Fuse

Drop Out Fuse is a type of fuse used in overhead power distribution systems, especially on medium-voltage lines. It's designed to disconnect or isolate a faulty section of the power line when a fault (like a short circuit or overload) occurs.

We are Drop Out Fuse manufacturers of different design for electrical overhead lines & substation. Our DO Fuse unit / set is suitable for worldwide uses with vertical & horizontal mounting features & operating mechanism from ground level. We are also suppliers of DO Fuse Link, element, spares etc.

Types : Channel | Bracket | Expulsion
Voltage : 11 KV | 22 KV | 33 KV
Current : 100 Amps | 200 Amps

Drop Out Fuse working :

1. Normal operation :

Electrical current flows through a fuse link (a metal wire or strip inside the fuse tube).
The fuse link is designed to carry normal current without damage.
The fuse tube is held in place between a hinged bottom contact and a spring-loaded top contact on an insulator mounted on a utility pole.

2. Fault or overload occurs :

If a short circuit or overload happens (e.g., due to a lightning strike, equipment failure, or a tree touching the line), the current increases beyond the fuse's rating.
The excessive current heats the fuse link, causing it to melt or vaporize.

3. Fuse link melts :

As the fuse link melts, it creates an arc (a flash of electricity trying to continue flowing).
The fuse tube is made of a special arc-quenching material (often a fiber tube lined with arc-extinguishing compounds) that helps to cool and extinguish the arc quickly.

4. Drop-Out action :

Once the arc is extinguished and the fuse link is fully broken :
- The fuse holder is released from the top contact.
- It swings down like a hinge, hanging from the bottom contact.
This "drop-out" motion makes it easy for utility workers to see—from the ground—that the fuse has blown.

5. Manual operation (optional) :

A drop-out fuse can also be opened manually using a hot stick for maintenance.
This makes it act like a switch in addition to a fuse.