Type of Earthing:-
TT (Separate):-
A separate earth electrode is provided for each electrical installation, and these electrodes are connected to the main earthing terminal through separateconductors.Offers a high level of safety against electric shock can be expensive to install due to the need for multiple earthelectrodes.
TN-S(Combined):-
A single earth conductor is used to connect all earth electrodes in the installation, and the same conductor is used to connect the electrical system to the earthelectrode.Cost-effective and easy to install.May not offer the same level of protection as another systems, as a fault in the earth conductor could resulting a break in the protective earth connection for the entire installation.
TN-C-S(Combined):-
Uses a single conductor for both the protective earth and the neutral conductor,which is separated at the point of supply.Cost-effective and easy to install.Can pose a risk of electrical shock if the neutral conductor is accidentally broken or damaged, and can be difficult to detect a broken neutral conductor.
IT (Isolated):-
The electrical system is completely isolated from the earth, and a separate earthing conductor is provided, which is connected to an earth electrodes. A monitoring device is used to detect any earth fault and sound an alarm. The fault must be located and repaired before the system can be used.Offers a high level of protection against electricshock.Can be more expensive to install than other systems, and requires regular testing and maintenance of the monitoring device. Incase of a fault, the system must be completely shut down and repaired before it can be used again.
TN-C(Combined):-
Uses a single conductor for both the protective earth and the neutral conductor,which is not separated at the point of supply.Can be cost-effective and easy to install an pose a risk of electrical shock if the neutral conductor is accidentally broken or damaged, and can be difficult to detect a broken neutralconductor.
TT (Separate):-
The TT earthing system is where each electrical device is connected to its own local earth electrode. The earthing electrode is connected to the earth pit directly, and not connected to any other conductive material. This type of earthing system is commonly used in residential areas.
TN-S (Combined):-
The TNS earthing system is a combination of the TN and TT earthing systems. The electrical devices are connected to a common earth point, which is then connected to both the earth electrode and the earth pit. This type of earthing system is commonly used in medium-sized industrial and commercial buildings.
TN-C-S (Combined):-
The TN-C-S earthing system is a combination of the TN and IT earthing systems. The electrical devices are connected to a common earth point, which is then connected to the earth electrode and the earth pit through a monitoring resistor. This type of earthing system is commonly used in larger industrial and commercial buildings.
IT (Isolated):-
The IT earthing system is where the electrical devices are isolated from the earth, and the only connection to the earth is through a monitoring resistor. The monitoring resistor is used to detect any earth fault currents and is typically set at a low value to ensure rapid detection. This type of earthing system is commonly used in sensitive electronic equipment.
TN-C (Combined):-
The TN-C earthing system is where the combined neutral and protective conductor (PEN) serves as the earth connection for electrical devices. The PEN conductor is connected to the earth electrodes, which is then connected to the earth pit. This type of earthing system is commonly used in small commercial and residential buildings.