Which statement is true regarding the use of fuses in modern electrical systems?

Fuses are a critical component in electrical systems, serving as protective devices that prevent damage to circuits from overloads or short circuits. The statement that they need to be replaced after operation accurately reflects their design and function. When a fuse operates—meaning it has blown due to excess current—it creates an open circuit, interrupting the flow of electricity. This interruption is intentional to protect the rest of the electrical system from potential damage or hazards.

Unlike circuit breakers, which can be reset to restore service after they trip, fuses must be physically replaced once they have blown. This characteristic underscores their function as sacrificial devices. Their simplicity and effectiveness have made them a reliable choice in various applications, despite the fact that they are less convenient than circuit breakers, which can be reset without needing replacement.

Understanding that a fuse must be replaced after it has operated reinforces the importance of proper maintenance and awareness in a modern electrical system. This knowledge is vital for safety and continuity in electrical work.