Design and Installation Practices

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

Diversity – Diversity is an allowance, per circuit, as not all electrical circuits are used to their full potential 100% of the time.

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) -The resultant resistive and reactive element of an ac circuit.

Line Conductor

Live Conductor

Overload – An over current occurring in a circuit which is electrically sound.

Reactance (X) -The opposition to electric current change in an ac circuit when an inductor and/or a capacitor is connected.

Resistance (R) – The opposition to electric current in a dc circuit.

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.