Reclosers and Fuses

Automatic circuit reclosers protect distribution circuits by interrupting and automatically reclosing an AC circuit according to a preset sequence.

Temporary faults, often caused by tree limbs or wildlife on overhead circuits, are cleared by reclosers, minimizing service disruption and improving customer experience.

However, reclosers can be hazardous if they contact energized ground-level conductors.

In radial distribution circuits, protection is achieved with a combination of fuses, reclosers, and time-delay overcurrent relays. These relays, with inverse characteristics, are coordinated with reclosers and Type T fuses.

Relay settings prioritize recloser operation to clear faults before relay activation.

If a fault persists, the recloser locks out, or fuses act on downstream faults. After several reclosures, time-delay overcurrent relays open the substation breaker.

Time-current curves represent coordination between reclosers and type T fuses.

Reclosers trip at minimum ratings above maximum load current, performing fast and delayed operations to clear temporary faults while allowing fuses to address permanent faults.