Double insulation is designed to prevent electric shocks by ensuring what condition?

Double insulation is designed to prevent electric shocks by ensuring what condition?

• A. The electrical parts can never come into contact with the outer casing
• B. The device has an earth wire
• C. The outer casing is made of metal
• D. The device uses a fuse inside

Answer: (A)

Double insulation works by keeping all live electrical parts away from the outer surface with two layers of insulation or a non-conductive shell. This creates no conductive path from the live parts to the casing, so the outer surface cannot become live and cannot shock a user, even if one layer wears. The surface staying non-conductive is the key protection. The other ideas don’t fit: relying on an earth wire isn’t needed because there’s no earth path in double-insulated designs; a metal casing would still need earthing to be safe, whereas double insulation is specifically designed to be safe without it; and a fuse protects against overcurrent, not the electrical surface being live.

Double insulation works by keeping all live electrical parts away from the outer surface with two layers of insulation or a non-conductive shell. This creates no conductive path from the live parts to the casing, so the outer surface cannot become live and cannot shock a user, even if one layer wears. The surface staying non-conductive is the key protection.

The other ideas don’t fit: relying on an earth wire isn’t needed because there’s no earth path in double-insulated designs; a metal casing would still need earthing to be safe, whereas double insulation is specifically designed to be safe without it; and a fuse protects against overcurrent, not the electrical surface being live.