Testing and Replacing a Cartridge Fuse

a variety of cartridge fuses on a counter
  • 1 hours
  • Intermediate
  • 20
What You'll Need
Replacement fuses
Fuse puller

A cartridge fuse is used in older buildings and houses to prevent circuit overloads. This means that the fuse is used to prevent the electrical panel from supplying an excessive amount of current throughout a circuit having defective wiring or appliance and causing a fire. A cartridge fuse is different than a circuit breaker because it cannot be reset once it trips. It might be a good practice to check and test fuses from time to time since they might be tripped and blown, or even cheated with a piece of foil or a coin. Here is how you can test the cartridge fuses in your electric panel in a few easy steps:

1. Prepare

circuit breakers in a panel

Preparation is very important when it comes to testing a cartridge fuse because you will need to take all necessary precautionary measures to be safe and avoid electrocution. One of the first things you need to do is go to the panel, turn it off completely, and then begin with the testing. Moreover, you need to use only proper tools and materials, as well as protective gear. You should have a pair of fuse pullers with you, which can be found at any local hardware store, or a store with electrical equipment.

2. Get to Know the Cartridge Fuse

Before you test the fuse, you need to know what it is about. There are two basic types of cartridge fuses available, so it all depends on the age and size of the house. Smaller and newer buildings have the cylindrical fuse which has some sensitive links at its ends, wrapped with copper or any other type of conducting material. Older and larger buildings usually have the knife blade fuses. You can check your electric panel at home and see what type of cartridge you have.

3. Remove the Cartridge Fuse

man holding a fuse puller

The next thing you need to do is remove the cartridge fuse from the panel slots. Open the panel and find the cartridge you want to test. Use the fuse puller in the middle part of the cartridge fuse and pull it out of the slot.

4. Test the Cartridge

The next step is about testing the fuse: take the fuse you have removed from the slot on a table and use the multimeter, setting it first to continuity, which means that you need to make sure it is set at the lower mark. Once you have the links of the meter on the sides of the fuse, the meter will show zero if the cartridge fuse works properly.

In the case the fuse is tripped or blown, the meter will read infinite. If the fuse is damaged, you need to replace it, plugging a new one at the slot from where you removed the original one. Always keep in mind that you need to do the replacement of the fuse using the puller, to avoid any injury.