- Earthing वह प्रक्रिया है जिसमें अनचाही विद्युत ऊर्जा को low resistance wire से सीधे earth में भेजा जाता है।
- इसमें non-current carrying parts (body/frame) या neutral को ground से जोड़ा जाता है।
🔹 Basic Concept
- Earth = Zero Potential
-
Leakage/Fault current हमेशा low resistance path चुनता है
👉 इसलिए earthing सुरक्षा देती है
🔹 Types of Earthing
1. Neutral Earthing (System Earthing)
- Neutral को earth से GI wire द्वारा जोड़ते हैं
- Use: Generator, Transformer (Star system)
2. Equipment Earthing
- Equipment की metal body को earth से जोड़ते हैं
- Fault आने पर current earth में चला जाता है
🔹 Need / Importance of Earthing
- ⚡ Electric shock से सुरक्षा
- ⚡ Fault current के लिए आसान रास्ता
- ⚡ Equipment को short circuit से बचाता है
- ⚡ Lightning और high voltage surge से protection
Need of Earthing
Earthing is needed for the following reasons −
To protect the user from electrical shock.
Earthing system shows the easiest path to the fault current even after the insulation failure.
It protects the electrical apparatus used in the circuit from short circuit current, high voltage surges and lightning discharges.
🔹 Working of Earthing
✔ Normal Condition
- All non-current parts electrode से जुड़े रहते हैं
- कोई current flow नहीं होता
✔ Fault Condition
- Fault current → earth में चला जाता है
- System सुरक्षित रहता है
🔹 Ground Resistance Measurement
- Method: Fall of Potential Method
-
Components:
- E = Main electrode
- P & C = Auxiliary electrodes
-
Formula Concept:
- Resistance = V / I
🔹 Important Standards (Exam में पूछते हैं)
- IS 3043 – Earthing Code
- NEC (1985)
- IEEE Standard 80-1986
🔹 Safety Points (Very Important)
- Proper inspection & maintenance जरूरी
- Soil resistivity check करना चाहिए
- Megger test use करें
- Corrosion और damage से protection दें
- Copper/Aluminium का गलत use न करें
🔥 Exam Tips (SSC JE / RRB JE)
- Earthing = Low resistance path ✔
- Types = Neutral + Equipment ✔
- Purpose = Shock + Equipment Protection ✔
- Measurement = Fall of Potential Method
Indian Standards: IS 3043- Code of practice for Earthing (latest)
National Electricity Code (NEC): 1985 of BIS
IEEE guide for safety in AC substation grounding No. ANSI/IEEE standard, 80-1986.
Proper inspection and field survey is necessary before the installation. A flowchart needs to be followed for the different steps: Inspection & Survey Design Testing Installation - Maintenance - Preparing Report.
Electrode resistance, soil resistivity is measured periodically and megger test should be exercised.
Do not use copper or aluminium wire as substitute, paint, enamel and grease on the electrode. Protect the electrode lead from mechanical stress and corrosion.
Proper training and management can reduce the risk factor
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