What is Electrical Earthing ?
The procedure used to transfer electrical energy to the earth directly in case of short circuit or fault is called electrical earthing. This is done by connecting neutral of supply to the ground or by connecting non current carrying part of equipment to the ground. Electrical earthing provides low resistant path to the high amount of current to the ground.
Electrical earthing is widely used for different applications which include telecommunication, lightning arrestor earthing, equipment body earthing, water treatment plants, residential buildings, banks, hospitals, heavy industries etc.
There are two methods for earthing viz. conventional earthing and maintenance free earthing. In the conventional earthing large pit is digged and GI (Galvanized Iron) pipe or copper plate is positioned in the middle layers of charcoal and salt as described below. This method requires maintenance and pouring of water at regular interval. Maintenance free earthing is new system which is standardized and scientifically developed.
The conventional earthing is categorized into plate earthing, pipe earthing, rod earthing, strip earthing and earthing through water mains.
The earth electrodes such as copper, cast iron or galvanised iron are used for earthing. The Earthing protects human being from electric shock. It also protects the expensive equipments or home appliances from damage due to high current in the event of SC (Short Circuit) or Fault. Salt and Charcoal are used as per following procedure along with pipe for Earthing. The layers of salt and charcoal help in maintaining low resistance and also to maintain moisture.
Electrical earthing procedure
Following items are used for electrical earthing. The quantity of these items vary based on power usage and
• Industrial salt (100 Kg)
• Charcoal (75 Kg)
• Copper plate (1 x 1 square feet)
• Copper wire 8mm diameter (5 Kg)
• MS earthing pipe (6 feet length, circular shape ) - 2 numbers , called earthing electrodes
• Underground power cable (35 mm diameter), length as per distance from pole to meter panel
Following steps are followed in rod based electrical earthing procedure.
• Step-1: Dig the earth near electrical meter panel about 6 feet deep and 2 x 2 feet wide
• Step-2: Connect the copper plate at the end of MS rod using copper bolts and wrape it with copper wire as shown
• Step-3: Insert the pipe in vertical position as shown with copper plate at bottom
• Step-4: Fill salt in the hollow part of the MS pipe as shown and also surrounding to it.
• Step-5: Put charcoal surrounding to the MS pipe as shown.
• Step-6: Put sand and concrete mixture surrounding to the pipe.
• Step-7: Repeat above three steps (4 to 6) several times till the opening made is filled till level of the earth.
• Step-8: Keep the copper wire above so it can be connected to appropriate place in the electrical meter panel.
• Step-9: One MS rod or pipe is fixed at electric pole side and the other is fixed at the meter panel side.
Following are the qualities of good earthing.
• Must be of low electrical resistance
• Must be of good corrosion resistance
• Must be able to dissipate high fault current repeatedly
10 Advantages of Earthing
Following are the benefits or advantages of Earthing:
1. It provides alternative path for the fault current to flow so that it will not endanger the user. It saves human life from danger of electrical shock or death by blowing a fuse.
2. It ensures that all the exposed conductive parts do not reach a dangerous potential.
3. Grounding safeguards electrical equipment and appliances from damage due to voltage surges, reducing the need for costly repairs or replacements.
4. It helps stabilize voltage levels in electrical systems, ensuring that equipment operates within its designated voltage range and prevents overvoltage conditions.
5. It provides safe path to dissipate lightning and short circuit currents.
6. It is essential for dissipating static charges, which can accumulate on objects and pose hazards in certain environments.
7. Grounding minimizes electromagnetic interference, which can improve the performance of sensitive electronic equipment and communication systems.
8. Grounding systems allow for the detection of ground faults, which can trigger protective devices like ground-fault circuit interrupters (GFCIs) to disconnect power, further enhancing safety.
9. Grounding minimizes electrical noise and interference in audio and video systems, ensuring better signal quality.
10. Proper grounding is often a legal requirement and ensures compliance with electrical safety codes and standards, helping to avoid legal liabilities.
5 Disadvantages of Earthing
Following are the drawbacks or disadvantages of Earthing:
1. Over time, grounding electrodes and conductors can corrode, which may increase resistance and reduce the effectiveness of the grounding system.
2. Grounding systems require regular maintenance to ensure they remain effective. Corroded or damaged components must be repaired or replaced.
3. Designing and implementing a proper grounding system can be complex, especially in large or specialized facilities, which may increase installation costs.
4. Some grounding materials, such as copper, can have environmental concerns related to mining and processing. Additionally, the disposal of old grounding materials can be an issue.
5. Improper grounding can be worse than no grounding at all. Inadequate grounding may provide a false sense of security and fail to protect against electrical hazards.
Conclusion : Electrical earthing, or grounding, offers numerous advantages, including enhanced safety by preventing electric shocks and protecting against lightning strikes and voltage surges. It stabilizes voltage levels, reduces electromagnetic interference, and dissipates static electricity, benefiting both equipment and personnel. However, it requires maintenance, can corrode over time, and may be complex to implement. Proper grounding remains essential for electrical safety and system reliability.
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