Double insulation prevents electrical shock without earthing

Steps:

• Earthing protects users by grounding metal casings if a fault occurs, diverting current safely.
• Some appliances lack metal parts or use insulation to avoid faults reaching the user.
• Double insulation adds two layers of non-conductive material, isolating live parts completely.
• This design ensures no path for current to escape, making earthing unnecessary.

Why C is correct:

• Double insulation, by definition, uses two independent insulating barriers around live components, preventing any contact with the outer casing and eliminating shock risk per electrical safety standards.

Why the others are wrong:

• A: A live wire carries current in all plugged-in appliances but does not prevent faults requiring earth.
• B: A neutral wire completes the circuit in standard appliances but offers no fault protection like earthing.
• D: Single cable insulation protects wires but not internal components, so earthing is still needed for safety.

Final answer: C