FAQ -Types of Electrical Fuses & How They Work

electric fuse box
Fuses & Breakers

In this post, our Abbotsford electricians answer the most frequently asked questions about the types of fuses available, plus how they work and how they should be used properly.

What Is A Fuse?

Fuses are devices that allow the flow of a standard electrical current and in some cases, a marginal percentage more. Although there are different types of fuses, all were designed as safety over-current devices to provide protection by breaking an electrical circuit if the current became excessive. Inside a fuse is a relatively small and slender conductor. If the current becomes too great, this thin conductor is designed to melt, separating into two pieces and thereby breaking the circuit.

How Are Fuses Rated?

The fuse rating is measured in “amps” and is usually found written on the side of the fuse. An amp is the unit of measurement for the incoming power, the electrical current. The ratings vary on different types of fuses and tell you how much current is needed (in amps) to break or blow the fuse.

How Do Fuses Work?

Fuses are designed to blow whenever the electrical current becomes too great or if there is a short-circuit, thereby breaking the circuit and eliminating the electrical power.

What Is A Short Circuit?

A short circuit usually occurs when an excessive amount of electrical current flows into the circuit from an accidental pathway that has very little or no electrical impedance. A loose wire, for instance, might cause a huge surge in electrical current and result in a short circuit.

What Is A Slow Blowing Fuse?

Slow blowing fuses are types of fuses designed to carry a small overload for a short period before actually blowing, even with the same maximum current level as for a fast blowing fuse.

What Are Some of the Different Types of Fuses?

An electrical fuse can either be a high voltage fuse or a low voltage fuse. An example of a low voltage fuse (1,500 volts or less) is the easy-to-replace cartridge fuse, where the fuse element and contacts are encased within the cartridge or body of the fuse. A low voltage fuse can also be rewireable (porcelain type) or semi-enclosed.

What Are the Disadvantages of Fuses?

While relatively inexpensive, once blown, fuses do need to be replaced with new fuses. As well, fuse boxes may have exposed electrical connections that can be potentially hazardous. Unfortunately, a blown fuse is often mistakenly replaced with a fuse that has a higher current rating, which can often lead to an overheated circuit. You also can’t use a fuse in any location that requires a GFCI outlet.

Summary

Most newer homes now use circuit breakers, but fuse boxes with different types of fuses can still be found in many older homes throughout the Vancouver Lower Mainland. The flow of an electrical current may not always be uniform. A large fluctuation in current could cause electrical devices to overheat and without a fuse (or circuit breaker), might even cause an electrical fire.

While an electrician can help you evaluate critical loads and choose the types of fuses required (with the correct ratings), at Premium Electric, we always recommend upgrading your fuse box to a circuit breaker. Unlike fuses, when circuit breakers become overheated they use switches that automatically trip (open) to stop an excessive electrical current.

About Premium Electric

Serving the Fraser Valley communities of Abbotsford, Chilliwack, Aldergrove, Mission, and Maple Ridge, Premium Electric specializes in both residential and commercial electrical services. We also offer 24-hour emergency electrical services and our work is warrantied and guaranteed.

If you have any questions about the different types of fuses, fuse boxes, or circuit breakers, or if you need an electrical safety inspection, please call us at 604-832-3016 or send us an email.

You might also like the our article entitled Electrical Panel Upgrades.