Automatic reclosers are pole-mounted circuit breakers that can quickly restore power after outages. Reclosers make quick work of many line faults, the great majority of which result from temporary insults such as a tree branch striking a line or the electrocution of an unlucky squirrel. Reclosers usually try restarting a line 2-3 times before giving up and “locking out” a line.
Reclosers solve many problems automatically and quickly, but they have also one potential disadvantage: they can increase fire risk from damaged lines. During restarting high-temperature electrical arcing often happens at the site of the fault. It can burn away hung trees or tree limbs, and sometimes spark a fire.
It is estimated that reclosers have had their part in Australia’s deadly Black Saturday bushfires in 2009 and fires in California in recent months.