Types of Earthing Systems.pptx

Earthing systems, also known as grounding systems, are crucial for electrical safety, and they come in various types. The choice of the earthing system depends on the specific requirements of the electrical installation and local regulations. Here are some common types of earthing systems:

TT System (Terre-à-Terre):

In a TT system, each electrical device or installation is individually grounded to the earth.
It is commonly used for residential buildings, where each outlet is connected to a local grounding electrode.
Provides a good level of safety but may require more ground electrodes.
TN System (Terre-Neutre):

In a TN system, the electrical devices are connected to a common grounding point, which is also connected to the neutral of the power supply.
There are three main variations of the TN system:
a. TN-S: Separate protective and neutral conductors.
b. TN-C: Combined protective and neutral conductors for part of the installation, with separate conductors for other parts.
c. TN-C-S: A combination of TN-C and TN-S within the same installation.
TN systems are commonly used in residential and commercial applications.
IT System (Isolated Terre):

In an IT system, the grounding is intentionally isolated from the power supply neutral.
This system is often used in critical applications where electrical continuity is vital, such as hospitals and data centers.
It provides a high level of reliability, especially in the event of a single fault.
Solid Grounding System:

A solid grounding system is characterized by a direct connection between the electrical system and a grounding electrode.
It is used in various applications to ensure that faults are quickly cleared and the electrical system is safe.
Impedance Grounding System:

An impedance grounding system involves adding resistance or reactance between the grounding electrode and the electrical system.
This type of grounding can be used to limit fault currents and reduce the risk of electrical shock and equipment damage.
Plate or Rod Electrodes:

These are physical grounding electrodes, such as copper rods or plates, that are buried in the earth to establish a connection to the ground.
Plate or rod electrodes are commonly used in conjunction with various grounding systems.
Counterpoise Grounding System:

This type of grounding is often used in radio and telecommunications systems.
A counterpoise is a network of wires, typically above ground, that serves as a ground reference for antennas and signal transmission.
Chemical Grounding:

In some cases, chemicals, such as conductive compounds or salts, are used to improve the conductivity of the grounding electrode, especially in areas with high soil resistivity.
The choice of the appropriate earthing system depends on factors like the local electrical codes, the type of electrical installation, safety requirements, and the environment. Proper earthing is crucial for electrical safety and the reliable operation of electrical systems.

1. EARTHING SYSTEMS TYPES OF

2. INTRODUCTION TO EARTHING SYSTEMS Definition: Earthing is an efficient way of protecting the appliances from electrical hazard when current surge or overload current is supplied. Purpose: To provide a safe path for fault currents and minimize electrical hazards.

3. COMMON TYPES OF EARTHING SYSTEMS TT System (Terre-Terre) Description: Separate grounding for each electrical installation. Application: Common in residential and small-scale installations.

4. COMMON TYPES OF EARTHING SYSTEMS 2. TN System (Terre- Neutre ) Description: Combined grounding for earth and neutral conductors. Types: TN-C, TN-S, TN-C-S. Application: Common in industrial and commercial installations.

5. COMMON TYPES OF EARTHING SYSTEMS 3. IT System (Isolated Terre) Description: No direct connection to earth; high insulation. Application: Sensitive environments like hospitals and data centers.

6. SELECTION CRITERIA Choosing the right earthing system depends on factors such as: Electrical load and equipment. Soil resistivity. Environmental conditions. Safety regulations and codes.

7. KEY CONSIDERATIONS Soil Resistivity Measurement Grounding Electrodes Selection Fault Current Path Step and Touch Voltage Analysis

8. EXAMPLES TT System Example: Residential Building TN System Example: Commercial Complex IT System Example: Hospital

9. ADVANTAGES AND DISADVANTAGES TT System: Simple but may offer limited protection. TN System: Common and balanced but can be affected by ground faults. IT System: High reliability but complex and costly.

10. CONCLUSION The choice of earthing system is critical for electrical safety. Selection should be based on specific requirements and regulations. Regular maintenance and testing are essential for the effectiveness of the chosen system.