Electrical safety is the protection of people and systems in order to prevent injury, damage and fire, and earthing is an essential safety feature built into the design of many different electrical systems. The purpose of earthing is to protect the user and the system from the dangers of electrical shock and equipment damage.
What is earthing?
Excessive current can be produced through various faults in an electrical system, and the design of these systems needs to provide a safe path for this excess current to be discharged. This is earthing. Earthing is the concept of diverting excess current into the earth in order to prevent hazardous voltages from building up and coming into contact with people and equipment.
Earthing works by establishing an effective route for the discharging of electrical current in order to neutralise its effects. If an electrical charge is not earthed it can accumulate more charge through cables and/or devices it is connected to until this becomes dangerously high, potentially causing electrical arcing and therefore injury, damage and fire.
How does earthing work?
The earth naturally has a negative charge and this can cancel out any positive charge it comes into contact with. So the ground can act as an absorbent body in which to divert any excess electrical energy. Therefore ‘earthing’ is the provision in an electrical system for a natural discharge of excessive electrical current. Most electrical systems, such as sockets and appliances for example, have an earth conductor incorporated into their design as an essential safety feature. This is a fail-safe wire that is intentionally designed to connect to the earth so that any surplus electrical charge can be diverted safely away from the user and the system and to a dissipating source, ie. the ground.
Most appliances have three wires in their electrical cords, and these will correspond with three pins in a plug socket. These systems have an earthing mechanism in that the third wire is attached to establish a connection between the frame or body of the appliance and earth. In some cases this is known as an earthing electrode, which is a conductive material with direct contact with earth, such as a metal rod driven into the ground, or a metal plate or a metal pipe. The physical connection with earth acts as a reference point for the electrical system and an access point for fault currents and therefore excess charge.
Other earthing instruments are copper or aluminium wires or a system known as ‘bonding’. This is where all the metallic and non-current-carrying parts of an electrical system are connected together and connected to the earthing system. This will avoid any potential differences between the conductive parts and will therefore avoid any electrical shock and damage to equipment.
So in conclusion, earthing is an essential safety mechanism within an electrical system, which ensures that any excess current that develops can be diverted to a safe source, before it comes into contact with the user, and before it causes damage to the system or device.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.