Bonding – Bonding is used to reduce the risk of an electric shock by connecting (metalwork) exposed and extraneous conductive parts together to form an equipotential zone (0V).
Current (I) – The flow of negatively charged electrons
Earth Fault – A current resulting from a fault of negligible impedance between a line conductor and an exposed conductive part r a protective conductor.
Earthing – Earthing is used to prevent an electric shock and is achieved by creating a low impedance path to ground. If an earth fault occurs a high fault current is obtained which is detected by the protective device disconnecting the circuit.
Electrical Discrimination – Electrical discrimination occurs when the nearest protective device to the fault operates leaving all other circuits in operation.
Impedance (Z) –
Overload – An over current occurring in a circuit which is electrically sound.
Reactance (X) –
Resistance (R) – The opposition to electric current.
Resistivity (ρ) – Each material has a specific resistance
Short Circuit – An over current resulting from a fault of negligible impedance between live conductors having a difference in potential under normal operating conditions.