Why does the car isolation battery disconnect switch have to disconnect the negative pole?

Because cars isolation battery disconnect switch are all single-du-wire systems to save space, the negative electrode of the battery is directly connected to the frame, and the negative electrode of the on-board electrical appliance can be connected to the body of the car 1653. So when disassembling the motor or generator, Just remove the negative terminal of the battery directly, so that you are not afraid of the wire touching the fire.

The negative terminal of a car is connected to the car body. The car body is made of metal. The entire car body leads to the negative electrode, which can also be understood as the negative electrode of the car body. In this way, the negative pole of any electrical component can be connected to the body ground, and the current will be transmitted back to the negative pole through the body. There is no need to pull a wire to the negative terminal for each component, which greatly saves the amount of wires and reduces circuit failures. Difficulty in maintenance.

If you remove the positive electrode of the battery, because the wrench is metal and conductive, if you accidentally touch the metal part of the car body during the disassembly process, it is equivalent to directly connecting the positive electrode of the battery to the negative electrode, causing the battery to short circuit. So the danger is that in the process of disassembly, after disassembly, whether it is the positive electrode or the negative electrode, the effect will be the same.