What device is primarily used for protecting electrical systems from voltage surges?

The surge arrestor is specifically designed to protect electrical systems from voltage surges, which can occur due to events like lightning strikes or sudden changes in connected loads. It works by diverting the excess voltage away from sensitive equipment and safely dissipating it. This device limits voltage spikes by providing a low-resistance path to ground during a surge event, thus preventing damage to components such as transformers, circuit boards, and other electronics that are vulnerable to high voltage.

In contrast, while a fuse is used for overcurrent protection by breaking the circuit when excessive current flows, it does not address voltage surges directly. A transformer alters voltage levels and is primarily used to step voltage up or down for distribution purposes, rather than surge protection. A capacitor can store and release electrical energy, but it does not inherently protect against voltage surges in the same way a surge arrestor does. Thus, the surge arrestor is the most appropriate device for the task of voltage surge protection.