Blade Fuse Kit assembly for Automotive Wiring Harnesses

Automotive fuses are often called blade fuse. The matching design of fuses is an important part of the overall vehicle principle design. It includes the selection of fuse type, capacity selection, fuse path setting, fuse sharing, etc.

1 – How the fuse works
Understanding the working mechanism of fuses is the prerequisite for correct fuse matching design. To fully understand the working mechanism of fuses, you only need to understand two questions:
1. Why do we need to add a fuse to the circuit?
2. How the fuse protects the circuit.

Selection blade Fuse & box for Automotive Wiring Harnesses

Why do we need to add a fuse to the circuit?
If there is no fuse in the circuit, once the circuit is overloaded or a short circuit occurs, the current in the circuit will inevitably increase. In this way, when the current flowing through the wire exceeds the carrying current of the wire, the wire will be overloaded and heat, melting the insulation layer and copper wire of the wire, or even spontaneous combustion, causing a safety accident.
Such a component that protects wires in a circuit is what we call a fuse, or fuse. A fuse is a thermal fuse device. It is intentionally designed and manufactured to be the weakest part of the line in order to protect the wiring harness. It is an electrical component that protects wires and electrical appliances. It is worth mentioning that in the circuit, the fuse can only protect the wires after the fuse, so the fuse should be set as close to the power supply as possible, as shown in the figure below. If the distance is too far, you need to consider setting up higher-level insurance.

The working principle of the fuse is to blow the wire in time when the circuit is short-circuited and the wire smokes and catches fire. In order to cut off the circuit and prevent the wire from burning and causing the entire vehicle to spontaneously ignite.
The specific working principle of the fuse is as follows:
Fuses have a certain resistance and the conductors heat up when current flows through them. As time increases, the amount of heat generated increases, and the current and resistance also increase the rate of heat generation. The construction of the fuse and its installation determine the rate of heat dissipation.
If: heat generation speed < heat dissipation speed, the fuse will not blow;
If: heat generation speed = heat dissipation speed, it will not fuse for a long time;
If: heat generation speed > heat dissipation speed, heat will accumulate, and when the temperature rise reaches above the melting point of the fuse, the fuse will blow.

Fuse box for car wiring harness

Introduction to the categories of fuses:
According to the appearance characteristics of fuses, they can be divided into:
Bladefuses. It consists of two blade-shaped plug-type input and output terminals, an electrical conductor composed of a fuse, and an insulator component. Also called plug-type, blade-type, blade-type fuses. Common models include AUTO, FKS, MINI, FK1, MAXI, FK3, and LP-MINI.
Cartridgefuses. It is composed of an electrical conductor component composed of two blade-shaped socket-type input and output terminals and a fuse, and a combined insulator component. Also called socket fuses and box fuses. Such as JCASE, LP-JCASE, MCASE.
Boltdownfuses. It consists of two blade-shaped plug-type input and output terminals suitable for screw connection, an electrical conductor component composed of a fuse, and a combined insulator component. Also called bolt-on fuses. Such as MIDI/BF1, MEGA.
Commonly used fuses in cars mainly include: Mega, Mini, Midi, and JCASE.
According to the blowing characteristics of fuses, they can be divided into:
Fast-blow type: suitable for small current and short-time pulse current loads.

Slow-blow type: suitable for large current and long-term pulse current loads.