An electrical short circuit occurs when the poles of a voltage source are connected with almost no resistance, resulting in an extreme current flow. Short circuits can be caused by direct contact between two separate wires, for example if a power supply unit is connected incorrectly.
Incorrect connection of cables, such as an incorrectly fitted power cable between the power supply unit and motherboard, carries the risk of short circuits. A regular check is recommended to prevent damage. Protective devices, such as fuses or circuit breakers, detect short-circuit currents and switch off defective cables.