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Earthing provides protection from
Over voltage
Under voltage
Leakage current
Over current
Leakage current
Earthing (or Grounding) provides a low-impedance path to the earth for leakage currents. It protects users from electric shock and equipment from damage by ensuring that any metal casing connected to a live wire through a fault is held at a potential near zero relative to the earth.
Earthing (or Grounding) provides a low-impedance path to the earth for leakage currents. It protects users from electric shock and equipment from damage by ensuring that any metal casing connected to a live wire through a fault is held at a potential near zero relative to the earth.
IfтАЛ=ReтАЛ+RfтАЛVтАЛ тАФ where IfтАЛ is fault current, V is supply voltage, ReтАЛ is earth resistance, and RfтАЛ is fault resistance
When insulation failure occurs, current flows through the appliance's metal enclosure. If the device is earthed, this fault current is diverted to the ground instead of passing through the human body. Because the earth wire has a significantly lower resistance than the human body, the fault current flows to the ground, often triggering an MCB or ELCB to disconnect the supply.
Earthing ensures the exposed metal parts of an appliance remain at ground potential (0V).
It works in conjunction with protective devices like ELCBs (Earth Leakage Circuit Breakers) or RCCBs.
The resistance of the earth electrode should be as low as possible for safety effectiveness.
IE Rule 33 states that every earth system shall be mechanically strong and maintained.
Prevents dangerous electric shocks to humans and animals.
Protects equipment from voltage surges and transients.
Provides a stable reference potential for electronic circuits.
Costly to install and maintain properly in rocky or dry soil conditions.
Requires periodic testing to ensure earth electrode resistance remains within limits.
Residential and industrial power distribution systems.
Telecommunication equipment shielding.
Lightning protection systems.
Over voltage is protected by Surge Arresters or Lightning Arresters.
Over current is protected by Fuses and MCBs (Miniature Circuit Breakers).
Under voltage is protected by Under Voltage Relays (UVR).
C is correct тАФ Earthing is specifically designed to safely bypass leakage current to the ground, preventing the accumulation of dangerous voltages on conductive surfaces.
Always remember: Fuses/MCBs protect against over-current (short circuits), while earthing protects against leakage current (ground faults). They are complementary systems.