Which piece of equipment is commonly used to protect against overcurrents in electrical systems?

The fuse is a crucial component in electrical systems for providing protection against overcurrents. It operates on a simple yet effective principle: when the current exceeds a predetermined level, the fuse element heats up and melts, thereby interrupting the circuit. This prevents excessive current flow that could lead to equipment damage, overheating, or even fire.

Fuses are designed to be sacrificial, meaning they must be replaced after they blow, which is a straightforward process. They are commonly used in various applications, from residential circuits to large industrial systems, due to their reliability and cost-effectiveness in protecting electrical infrastructure.

Other equipment, such as switchgear, is primarily focused on switching, controlling, and protecting electrical circuits but may include fuses or miniature circuit breakers as part of their protection scheme. Transformers, on the other hand, are used to change voltage levels and do not provide overcurrent protection. Relays can protect circuits by conducting power or breaking a circuit when a certain condition is met, but they typically work in conjunction with other protective devices, including fuses, rather than serving as a standalone solution for overcurrent protection. Thus, the fuse is the most directly applicable piece of equipment for preventing overcurrent damage.