Effects of Electrical Faults
Modern electrical devices are usually very reliable and do not normally pose a risk of injury or damage. At the end of their life, devices will normally fail without any serious implications - they just stop working.
In some cases, however, a fault either within the device or with its supply cabling will cause it to pose a substantial risk. For example, a mains supply cable might become worn through due to prolonged rubbing against another object and directly connect the power to the ground. Similarly a motor may burn out, causing a short circuit.
Electrical faults may also be caused by people accidentally - such as a person cutting a cable, for example while cutting grass with an electric mower or spilling tea on an electrical device.
Electrical faults pose risks of fire, damage to other equipment and potential electrical shocks to people. Fire risks occur because in many electrical faults there is a short circuit between the supply and ground. In this case the current flowing increases dramatically, which in turn causes overheating of wires and components in the device, and also in wires in the supply leading to the device. If this heat is left to build up then there is a substantial risk of fire to the device and the supply wires.
The risk of damage to equipment is mainly to the other devices in close proximity and to the supply wires. If a short circuit is not removed then the mains cabling in the wall or under the floor would suffer severe damage and would require replacing, at considerable time and cost.