Earthing

Earthing – Verified PYQ Authority Guide

Earthing is organised as a topic-level PYQ authority page. It brings together the strongest verified question clusters, exam/year coverage and concept-level practice so students can revise the topic without jumping through unrelated notes. Every factual learning cue below is drawn from the existing verified, published and approved English PYQ corpus or from its Knowledge Graph relationships; the hub does not invent unsupported technical claims.

PYQ evidence snapshot

3 verified PYQs are currently mapped to this Topic hub. The represented years include 2024. Exam coverage currently includes Vidyut Sahayak (Junior Engineer - Electrical). Subject context includes Electrical Engineering. These values come from live mappings and can expand automatically when new verified PYQs are added.

Most useful verified PYQs to solve first

Start with the actual questions rather than memorising a generic note. The links below are ranked from the mapped corpus using repeat history and editorial quality, while the complete explanation stays on the individual question page.

1. What is the effect of present of salt on resistivity of soil?
   Vidyut Sahayak (Junior Engineer - Electrical) · 2024 · Effect of Salt Content on Soil Resistivity
   B — Resistivity decreases with increase in salt content. Dissolved salts add mobile ions to moist soil and increase its electrical conductivity.
2. Earthing of electrical equipment is necessary to prevent:
   Vidyut Sahayak (Junior Engineer - Electrical) · 2024 · Shock Protection by Equipment Earthing
   C — Electric shock. Protective earthing bonds exposed conductive parts to a fault-current path and works with automatic disconnection to reduce shock risk.
3. What is the maximum permissible earth resistance for large power stations?
   Vidyut Sahayak (Junior Engineer - Electrical) · 2024 · Maximum Earth Resistance for Large Power Stations
   C — 0.5 Ω. This is the large-power-station earth-resistance value expected in the supplied examination.

Formula & key-relationship bank from verified solutions

• ρ = 1/σρ in Ω·m; σ in S/m
• Touch voltage approximately: Vtouch = If × Zearth-pathLower fault-path impedance → larger protective fault current → faster disconnection
• Vgrid ≈ IgRg

Use these as revision triggers and open the linked PYQ before applying a formula numerically; variable definitions and assumptions belong to the exact solved question.

Core ideas repeatedly reinforced by the solved corpus

• B — Resistivity decreases with increase in salt content. Dissolved salts add mobile ions to moist soil and increase its electrical conductivity.
• C — Electric shock. Protective earthing bonds exposed conductive parts to a fault-current path and works with automatic disconnection to reduce shock risk.
• C — 0.5 Ω. This is the large-power-station earth-resistance value expected in the supplied examination.

Exam tips already validated in SRO solutions

• Think conductivity first: more mobile ions → σ↑ → ρ↓.
• Ask: ‘What happens if a live wire touches the metal body?’ Earthing provides the protective fault path.
• In earthing MCQs, larger fault level generally means a stricter (lower) target earth resistance.

Common mistakes to avoid

• Confusing soil resistivity with corrosion rate; salts can lower resistivity while simultaneously increasing corrosion risk.
• Saying earthing prevents overload. It protects against dangerous exposed-conductive-part voltage during earth faults.
• Memorizing one earth-resistance value for every installation type; permissible targets differ by application and standard.

Topic and concept coverage

Mapped topic labels include Earthing. The concept trail includes Effect of Salt Content on Soil Resistivity, Maximum Earth Resistance for Large Power Stations, Shock Protection by Equipment Earthing. Use these labels as a revision map: move from the broad area to the narrow concept, solve a verified PYQ, inspect the detailed reasoning, and then attempt another question from the same cluster.

Knowledge Graph navigation

Continue with Electrical Installation & Safety, Earth Resistance, Protective Earthing, Soil Resistivity, Electrical Engineering, Effect of Salt Content on Soil Resistivity, Maximum Earth Resistance for Large Power Stations, Shock Protection by Equipment Earthing. These are canonical SRO entity links based on the Knowledge Graph and shared question mappings, not keyword-stuffed tag pages.

How to revise this authority page efficiently

1. Solve before reading: answer a mapped PYQ first.
2. Read the exact explanation: verify the correct principle, formula, distractor logic and common mistake on that question page.
3. Move one level in the graph: use the closest concept/sub-topic/topic link rather than opening unrelated content.
4. Reattempt: solve another verified PYQ from this hub and check whether the same error repeats.

Quality scope: this page is automatically maintained from SRO’s verified mapped corpus. It enriches one canonical authority URL instead of generating multiple near-duplicate pages for keyword variants. Manual authority articles are never overwritten by the automated engine.