What protective device operates instantly to stop a short circuit condition?

Fuses serve as protective devices that are designed to operate instantly in the event of a short circuit condition. When excessive current flows through a fuse due to a fault, such as a short circuit, the fuse element quickly heats up and melts, interrupting the current flow. This immediate response is crucial for protecting electrical components and wiring from damage that could occur due to overheating and excessive currents associated with short circuits.

Overload relays, while also protective devices, typically do not act as quickly as fuses; they are designed to protect against sustained overloads rather than instantaneous short circuits. Capacitors and resistors do not function as protective devices in this context; capacitors store charge and can smooth out voltage fluctuations, while resistors primarily limit current flow but do not provide the immediate disconnection needed during a short circuit. Therefore, fuses are the most effective device for immediate interruption in the event of a short circuit.