Which safety device is reusable and breaks the circuit when the current is too high?

The correct choice identifies a circuit breaker as the reusable safety device that breaks the electrical circuit when the current exceeds a safe level. Circuit breakers are designed to prevent electrical overload and protect wiring from overheating, which can lead to fire hazards. When the current flows through the breaker is too high, it triggers a mechanism that opens the circuit, stopping the flow of electricity. This resetting capability allows users to restore functionality without replacing the device; instead, they can simply reset the breaker once the issue causing the overload is resolved.

In contrast, a fuse serves a similar protective function but is typically a one-time use device. Once it blows due to excessive current, it must be replaced, making it less convenient than a circuit breaker. Generators do not function as safety devices; instead, they are power-producing equipment. Resistors, while they manage current flow and can create heat, do not provide circuit protection in the event of an overload. Thus, the circuit breaker is specifically developed for the role of interrupting current, making it the appropriate choice.