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Fuses 101: Finding the Right Fuse to Fit Your Vehicle's Needs

Power - by Bryan Veldboom - updated on 4/10/2020

Collage of fuses

Did you know that the average vehicle contains 90 individual fuses? According to Littelfuse opens in new window, the worldwide leader in circuit protection, vehicle fuse and circuit breaker applications have grown by 400% over the last ten years. With that many fuses in your car, truck or motorcycle, you’re sure to need a replacement at some point in your vehicle’s life. Fortunately, Batteries Plus Bulbs now carries an expanded assortment of quality fuses from Littelfuse perfect for cars, trucks, boats, construction equipment and more.

What is a Fuse and Why Does Your Car Need One?

Let’s start with some basic facts. Much like the fuses found in your house, vehicle fuses are an important safety device designed to stop current from overloading your electrical system. If the current in your vehicle exceeds the safety rating of the wires or components, the fuse will melt in order to open the circuit and stop the flow of harmful electric current. This prevents excessive current from causing damage to your electrical system.

Types of Fuses

Here are a few of the different types of fuses currently available from Batteries Plus Bulbs.

Blade Fuses

Blade fuses feature a two- or three-pronged design made to fit into a small plug. In addition to cars, blade fuses can also be used in a number of additional applications, including RC cars, mobility scooters, segways, lawn tractors, sump pumps, motorcycles, mopeds, boats, snowmobiles, ATVs and other off-road vehicles. Blade fuses are easily inserted directly into a vehicle’s fuse holder without the need for additional tools.

Cartridge Fuses

Cartridge fuses feature the opposite design of a blade fuse. Instead of a pair of prongs, a cartridge fuse has a hole which enables it to be plugged into a fuse holder. In 1997, Littelfuse introduced the first Cartridge fuse (JCASE). It was created as a compact version of the MAXI Blade Fuse for domestic autos beginning in 1998.

JCASE

The JCASE is a cartridge style fuse that provides both an increased time delay and low voltage drop, enabling it to protect high current circuits. JCASE also has the ability to handle inrush currents (the initial high input current drawn by equipment when it is turned on).

JCASE fuses are currently used in many new domestic, European, and Japanese model cars. A smaller version is currently being designed by many OEM (original equipment manufacturer) companies. JCASE fuses teature a double spring-beam box terminal, as well as a unique secondary locking feature which holds the terminal firmly in place.

Low Profile JCASE (LPJCASE)

The Low Profile JCASE (LPJCASE) fuse has similar performance characteristics to the standard JCASE fuse, but with a smaller size. This compact design saves both space and weight, while allowing for a shorter male blade terminal. Both JCASE and LPJCASE fuses can be found in a number of OEM Emergency Fuse Kits that we offer for Ford, GM, Chrysler/Dodge/Jeep, and VW/Audi vehicles.

MCASE

MCASE cartridge fuses feature a slim, compact design, making them ideal for applications with limited space. Much like JCASE fuses, the MCASE also features a time delayed fuse and can handle inrush current.

Glass & Ceramic Fuses

Glass Fuses

Glass fuses have a low rupturing point making them perfect for small items that don’t draw a heavy amount of current. These fuses are ideally suited to consumer electronics, appliances and vehicle electronics, and can be found in cars made prior to 1981.

Ceramic Fuses

A ceramic fuse is built to withstand higher temperatures and are commonly used in a variety of household items, such as extension cords and ceiling fans. A thermoplastic, torpedo-shaped variety is also used in many European cars.

Heavy Duty Vehicles & Equipment

In addition to common vehicles like cars, trucks and motorcycles, we also carry MEGA and MIDI fuses for a variety of heavy-duty vehicles. Unlike blade and cartridge fuses which can be inserted directly into a fuse holder, both MEGA and MIDI fuses are bolt-down types that need to be secured to the fuse holder with a screw, nut or bolt.

MEGA Fuse

The Littelfuse MEGA Fuse is designed for circuit protection of up to 500A. It is ideal for battery and alternator protection and other heavy gauge cables that require an ultra-high current protection. The Mega fuse also incorporates a special Diffusion Pill Technology that lowers the fuse’s melting temperature and adds a time delay element. This is especially useful in heavy-duty motors that require more electricity to start than they do to operate. The MEGA fuse is OEM on Ford, GM and Chrysler vehicles. Note, MEGA Fuses are not available online, but can be ordered at your local Batteries Plus Bulbs location.

MIDI Fuses

In 1993, Littelfuse collaborated with Chrysler and BMW to design the MIDI fuse, which is now OEM on Chrysler and BMW vehicles. The MIDI style fuse is a bolt-down space-saving fuse for high current wiring protection. It provides time delay characteristics with the same Diffusion Pill Technology used in MEGA Fuses. Plus, its Slo-Blo feature helps to eliminate instances of fuses blowing out during temporary, short duration overloads. Note, MIDI Fuses are not available online, but can be ordered at your local Batteries Plus Bulbs location.

Emergency Fuse Kits

It’s important to note that The Federal Motor Carrier Safety Regulations require all commercial vehicles to carry spare fuses during transit. Littlefuse makes this easy with its line of convenient Emergency Fuse Kits. Each kit contains fuses with the proper amperes for different vehicle types, as well as fuse pullers to fit each variety. We carry several Emergency Fuse Kits including an ATO Kit, and a MINI Kit, as well as several Emergency Diagnostic Fuse Kits including an ATO/MINIDiagnostic Kit, ATODiagnostic Kit, and a MINI Diagnostic Kit.

Both MEGA and MIDI fuses are ideal for the following applications:

  • Street trucks (semi truck, snowplow, bucket, garbage, sweepers)
  • Buses & RVs (school, commercial, transit, motor homes)
  • Construction (backhoes, pavers, bulldozers, compactors, dump trucks)
  • Agriculture (harvesters, combines, tractors)
  • Emergency vehicles (ambulance, fire, police)
  • Material handling (forklift, pallet jack)

Selecting The Right Fuse

Each fuse contains a rating (or amperage) that denotes the maximum current (in amperes) that each fuse can carry. When selecting a replacement fuse, always be certain that the fuse rating matches the amperage of the circuit you’re using it in. You can find this information by consulting the owner’s manual of your vehicle or by checking to see if it is written on the fuse block itself.

If you’re uncertain what type of fuse you need, or have any additional questions, you can contact the associates at your local Batteries Plus Bulbs or shop our full assortment of fuses online. They’ll be happy to walk you through our selection of fuses and help you find the right one to fit your individual needs.