In electrical terms, earthing, commonly known as grounding, refers to a system designed to protect electrical wires and components from damage caused by sudden electrical power surges. Its main purpose is to reduce the risk of dangerous electrical shocks from uninsulated metal parts of an appliance or electrical device. Earthing systems also prevent end users from electrical shocks in the event of a short circuit.
A solid copper grounding rod, also called grounding electrode, driven into the soil outside of the house and connected to the main electrical panel by a single earth-grounding wire is the primary method of earthing modern household electrical systems. Since electricity follows the path of least resistance, an appropriately earthed electrical system discharges harmful power surges to the soil safely.
The system also protects electrical devices, such as home appliances, machinery and power tools, via a three-wire power plug. The extra wire, the grounding wire, is connected to the device's circuit protection system and harmlessly carries electrical surge away to prevent electrocution of users. On some appliances, a grounding wire must be fastened to metal water pipes to prevent electrical shocks.
Factories also use grounding systems to protect equipment and machinery from accumulating static electrical charges to ensure safety of workers against electrocution.