How To Buy Fuses For Home Electrical

Fuses monitor electrical currents and make sure they operate within safe levels to prevent fires


Fuses are used in everything from automobiles and computers to appliances and home wiring systems. If they detect unsafe levels, fuses break the connection to prevent wire damage from occurring and reduce the risk of electrical fires.

This buying guide highlights the different types of fuses, along with ratings and selection tips.

Fuse Types

Fuses contain small wires that allow current to flow across uninterrupted, until unsafe levels are detected

  • Plug fuses have a threaded base that looks like the base of a traditional light bulb. It is important to match the specs of the existing fuse to the replacement fuse to avoid dangerous current levels.
  • Tamper-proof, or type-S, fuses provide protection by using special adapters in the fuse box. They screw into the fuse opening and only accommodate one size, making it impossible to insert a fuse that is not rated appropriately.
  • Cartridge fuses have a cylindrical body with metal end caps, which connect with a wire inside the body. Once snapped into the electrical panel, the connection is complete, enabling the current to flow.
  • Cartridge fuses are normally used for more demanding applications such as water heaters and clothes dryers that require higher current loads.
  • Time-delay fuses are rated on how long they can withstand higher current levels before breaking. These should always be used in motor-driven devices, along with fuses that are rated as dual element that allow for even longer time delays by absorbing extraneous heat and taking pressure off the main wire upon start up.

Rating and Selection

To ensure you’re using the right fuse, it is important to understand the significance of ratings:

Rating Indicates Selection Tips


The level of electrical current the fuse can withstand without melting

  • Referred to as “amps”
  • Rating is stamped directly on the fuse
  • Match replacement fuses to the existing fuse’s exact amperage rating

Interrupting Rate

Determines the highest current at the rated voltage that must be reached before a fuse will break the circuit

  • This rate is typically higher than the amperage rating
  • Indicates the level of protection present in a fuse under normal conditions


Determines how long the fuse can sustain an overload before breaking the circuit

  • Units with a dual element often allow for longer time delays
  • Fast-acting units break more quickly and help protect sensitive devices


The maximum voltage a fuse is designed to interrupt

  • Always choose a fuse that is equal to or higher than the voltage in the circuit
  • Fuses not rated to handle incoming voltage levels may be unable to interrupt the circuit