Colorado Journeyman Practice Exam

The device used to prevent overcurrent in electrical circuits is a circuit breaker. A circuit breaker is designed to automatically interrupt the flow of electricity when it detects an overload condition or a short circuit, thereby protecting the wiring and connected devices from damage due to excessive current. This protective function is critical in ensuring the safety and reliability of electrical systems.

While a fuse also serves the purpose of preventing overcurrent, it does so by melting its internal element when the current exceeds a certain level, which requires replacement after it operates. In contrast, a circuit breaker can be reset after it trips, making it a more convenient and reusable solution in many situations.

Voltage regulators and transformers do not serve the function of overcurrent protection. Voltage regulators are used to maintain a constant voltage level, while transformers change voltage levels between circuits, neither of which directly addresses the issue of overcurrent.