Regarding electrical safety and protection devices:1.An RCCB (Residual Current Circuit Breaker) protects against earth leakage currents,which helps prevent electric shocks.2.An MCB (Miniature Circuit Breaker) provides protection against both overload and short-circuit faults.3.Surge Protection Devices (SPDs) are designed to handle sustained overvoltage conditions.Which of the statements given above is/are correct?

Correct Answer: A - 1 and 2 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 RCCB (Residual Current Circuit Breaker) protects against earth leakage currents, which helps prevent electric shocks.
  An RCCB/RCD detects imbalance between live and neutral currents caused by leakage to earth and is used for shock protection.
• Statement 2 - Correct.
  An MCB (Miniature Circuit Breaker) provides protection against both overload and short-circuit faults.
  An MCB protects conductors against overload and short circuit.
• Statement 3 - Incorrect.
  Surge Protection Devices (SPDs) are designed to handle sustained overvoltage conditions.
  An SPD is designed for short-duration transient surges, not sustained overvoltage regulation

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

Exam Shortcut / Approach

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

Common Mistake

Do not expect an RCCB alone to provide overload protection.

Quick Revision

Shock Overcurrent and Surge Protection is linked with RCCB MCB and SPD, Protection Devices and Electrical Safety. RCCB → leakage; MCB → overcurrent; SPD → transient surge.