Consider the following regarding Earth Leakage Protection:1.An ELCB (Earth Leakage Circuit Breaker) detects small leakage currents to the earth.2.Voltage-operated ELCBs are preferred over current-operated RCCBs in modern installations.3.A 30mA RCCB is generally used for personal protection against electric shock.Which of the statements given above is/are correct?

Correct Answer: B - 1 and 3 only

Quick Concept Explanation

An RCCB/RCD detects imbalance between live and neutral currents caused by leakage to earth and is used for shock protection. An MCB protects conductors against overload and short circuit. Key relation: Typical additional personal protection uses 30 mA RCD/RCCB.

Exam focus: RCCB → leakage; MCB → overcurrent; SPD → transient surge. Common trap: Do not expect an RCCB alone to provide overload protection.

Statement-wise Verification

• Statement 1 - Correct.
  An ELCB (Earth Leakage Circuit Breaker) detects small leakage currents to the earth.
  An RCCB/RCD detects imbalance between live and neutral currents caused by leakage to earth and is used for shock protection.
• Statement 2 - Incorrect.
  Voltage-operated ELCBs are preferred over current-operated RCCBs in modern installations.
  Modern installations prefer current-operated RCCBs/RCDs because they directly sense residual current and are more comprehensive
• Statement 3 - Correct.
  A 30mA RCCB is generally used for personal protection against electric shock.
  An RCCB/RCD detects imbalance between live and neutral currents caused by leakage to earth and is used for shock protection.

Core Concept

An RCCB/RCD detects imbalance between live and neutral currents caused by leakage to earth and is used for shock protection. An MCB protects conductors against overload and short circuit. Surge protective devices clamp short-duration transient overvoltages; they are not intended to regulate sustained overvoltage.

Formula / Key Relationship

Typical additional personal protection uses 30 mA RCD/RCCB.

Why the Other Options Are Wrong

Option A is incorrect because it includes incorrect statement(s) 2 and omits correct statement(s) 3. Option C is incorrect because it includes incorrect statement(s) 2 and omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 2.

Exam Shortcut / Approach

RCCB → leakage; MCB → overcurrent; SPD → transient surge.

Common Mistake

Do not expect an RCCB alone to provide overload protection.

Quick Revision

30 mA Personal Protection is linked with ELCB and RCCB, Earth Leakage Protection and Electrical Safety. RCCB → leakage; MCB → overcurrent; SPD → transient surge.