Which component is specifically designed to protect the main line from faults on tap lines?

The component specifically designed to protect the main line from faults on tap lines is fused cutout switches. These switches serve a critical function in a distribution system by providing overcurrent protection. When a fault occurs on a tap line—such as a short circuit—the fused cutout switch will detect the excess current and operate to disconnect the tap line from the main line. This action prevents the fault from affecting the entire main line supply and minimizes the risk of widespread outages. The fused element within the cutout is designed to blow under fault conditions, effectively isolating and protecting the upstream system.

In contrast, reclosers are typically designed to automatically restore power after a momentary fault by temporarily disconnecting the power and then re-energizing the line. Capacitors are used for power factor correction and voltage regulation rather than fault protection. Sectionalizers work in conjunction with reclosers but are not primary devices for protecting from faults; they help isolate segments of the circuit during a fault condition identified by the recloser.