Fuses have something to do with electricity and occasionally they blow? That’s all most of us know about fuses. There are fuses in the wiring of our buildings, the cars we drive, the appliances in our kitchens and most of the electronics around us. So we should probably find out why we need fuses and what types of fuses are out there.

What are fuses?

Fuses are heroic little (and sometimes not so little) components that sacrifice themselves to protect the rest of their circuit and the more delicate and expensive components in it. You can get fuses in many shapes, sizes and configurations. Each fuse is designed to “blow” at a specific current level.

How does a fuse work?

Every fuse contains a metal “element” that is essentially a wire with a current tolerance lower than the most fragile component of the system. When there is too much current in the system due to a surge or short circuit the element has a meltdown, literally. This breaks the circuit and prevents the overload from damaging more expensive components. Obviously you need to replace the blown fuse before the circuit will work again. Since they are meant to be sacrificed fuses are usually easy and relatively cheap to replace.

What if I use the wrong fuse?

At worst your fuse element will not melt soon enough or fast enough and you will damage your equipment. At best your fuse will blow too early or too fast and you’ll have to replace it even though there was no danger to the system.

What types of fuses are there?

There are many, many shapes, sizes, and ratings of fuses. Rather than explain every type of fuse here, I’m going to point you to Swe-Check. They have a wonderful set of articles, written in plain English, on fuses. Learn how to test for a blown fuse and how to identify a fuse and interpret it’s markings. They also have a dictionary of terminology and a library of more in depth pdf articles.  Have a look, there is some really fascinating and useful information there.

If you’re interested in electricity have a look at these articles.