What is the primary function of a sectionalizer in a distribution feeder?

• A. To reclose automatically after a fault
• B. To monitor current and provide status
• C. To isolate a faulted section to restore service quickly
• D. To switch power between feeder sections

Answer: (C)

Isolating the faulted section to restore service quickly is what sectionalizers are designed to do. They are placed along a distribution feeder to divide it into sections, and after a fault is cleared by the upstream protection, the sectionalizer opens to separate the faulted segment from the rest of the feeder. This minimizes the number of customers affected by a fault, since the remainder of the feeder stays energized while only the faulty section is taken out of service. Unlike a recloser, which automatically closes back after interrupting a fault, a sectionalizer does not reclose. It may monitor current to help detect faults, but its primary purpose is to isolate the faulted section, not to switch power between feeder parts.