Swapping vs. Reverse-Polarity
Effects of accidental Swapping of power plugs
Applicable to these products
What may happen, if one swaps the +- and −-line?
Although the displays are protected against negative voltage, there may still be situations in which very high currents can flow if the supply lines are connected incorrectly.
The ground potential of the PC is connected to that of the display via data cables such as DVI or USB. If the black plug of the display supply is now plugged into the positive pole of the battery or the supply, a very high short-circuit current flows through the ground connections of the devices. This path is thickly drawn in the diagram above.
If, on the other hand, the entire system is connected in a reverse way or a vehicle is supplied with a reversed start-up aid, the built-in polarity protection works.