Distinguish between overload protection and short-circuit protection.

• A. Overload protection prevents damage from excessive continuous current; short-circuit protection interrupts very high fault currents.
• B. Overload protection interrupts sudden faults; short-circuit protection stabilizes voltage.
• C. Overload protection and short-circuit protection are the same.
• D. Overload protection is only for DC circuits; short-circuit protection is only for AC circuits.

Answer: (A)

The key idea is that protection distinguishes between sustained overcurrent and a sudden, severe fault. Overload protection guards equipment when current stays above its rating for a longer period, so it’s designed with a time delay to avoid nuisance trips from normal transients. It prevents overheating and damage from excessive continuous current. Short-circuit protection targets very high fault currents produced by a direct fault, and it must act almost instantly to stop damage, using instantaneous trips or fast-acting fuses.

So the best description is that overload protection prevents damage from excessive continuous current, while short-circuit protection interrupts very high fault currents. The other statements mix up the functions or the conditions they address, or claim constraints (like DC vs AC only) that aren’t true.