Chinese manufacturer of fuse harness
Before discussing how to design the fuse box and wire diameter, let's talk about the matching of the wire harness and the fuse. This is also helpful for us to better understand the problem of the fuse box later.
First of all, we need to determine the capacity of the fuse according to the current characteristics of the load and the working environment of the fuse, and then calculate the required wire diameter according to the load characteristics and the environment of the wiring harness. For a circuit protected by a fuse, it is necessary to confirm the matching of the wiring harness and the fuse before determining the wire diameter.
The calculation of the fuse capacity is actually the calculation of the rated operating current. However, if the load contains inrush current, the calculation of inrush current is also required. After initially determining the capacity, check the life of the fuse for the inrush current until its capacity is finally determined.
The general selection can be divided into:
a. Fuse capacity> working current of electrical appliances or motor stall current (generally <70% of fuse capacity)
b. Wire capacity> fuse capacity power consumption (generally <85% capacity at wire grade temperature)
c. Switching capacity> fuse capacity power consumption (generally <85% of switching capacity)
d. Relay capacity> fuse capacity power consumption (generally <85% of relay capacity)
e. Connector terminal> fuse capacity power consumption (generally <85% of terminal capacity)
The wire diameter calculation first is the calculation of the rated current, which needs to consider the load characteristics, the ambient temperature of the wiring harness, and the number of power circuits in the same branch wiring harness. For a circuit protected by a fuse, a matching calculation is required to ensure that the time when the wire starts to smoke is greater than the melting time of the fuse. Finally, check the short-circuit current to ensure that the short-circuit current is sufficient to blow the fuse in time when a fault occurs.
