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Earthing is necessary to give protection against
Danger of electric shock
Voltage fluctuation
Overloading
High temperature of the conductors
Danger of electric shock
Earthing provides a low-impedance path to the ground for fault currents, ensuring that the metallic enclosure of an electrical appliance remains at a safe potential close to zero volts. This prevents the development of dangerous touch voltages when insulation failure occurs.
Earthing provides a low-impedance path to the ground for fault currents, ensuring that the metallic enclosure of an electrical appliance remains at a safe potential close to zero volts. This prevents the development of dangerous touch voltages when insulation failure occurs.
VtouchтАЛ=IfтАЛ├ЧRgтАЛ тАФ The potential difference appearing on the chassis during a fault, where IfтАЛ is fault current and RgтАЛ is grounding resistance.
When insulation failure occurs between a live conductor and the metallic frame of an equipment, the fault current flows through the earth conductor instead of a human body touching the frame. Because the earth path has significantly lower impedance than the human body, the majority of the current follows the ground path, triggering protective devices like the MCB or ELCB to isolate the circuit rapidly.
The primary goal of earthing is human safety against electric shock.
Earthing ensures the equipment frame remains at zero potential relative to the earth.
It facilitates the operation of protective devices by allowing sufficient fault current to flow.
Reduces the risk of fire due to insulation leakage current.
Prevents dangerous voltage buildup on non-current-carrying parts.
Provides a reference point for stable system operation.
Protects equipment from surge voltages.
Corrosion of earth electrodes over time increases resistance.
Requires regular maintenance and periodic testing.
Complexity in areas with high soil resistivity.
Domestic wiring systems.
Industrial power distribution networks.
Sub-stations and transmission towers.
Communication equipment grounding.
Standard values for earthing resistance are typically < 1 ╬й for major power stations and < 5 ╬й for small substations.
Option B (Voltage fluctuation) is managed by voltage stabilizers/regulators, not earthing.
Option C (Overloading) is managed by circuit breakers and fuses.
Option D (High temperature) is managed by proper ventilation and cable sizing.
A is correct тАФ Earthing is fundamentally designed to protect human beings and equipment from electric shock by safely discharging fault current to the earth.
Always remember: Earthing is for safety (shock protection), while Neutral is for circuit completion (current return path). Never confuse the two.