Why Are The Low-voltage Pole-mounted Circuit Breakers On Each Line Distributed In A Tiered Manner?

When a fault occurs in the power system, if the lower-level circuit breaker fails to trip promptly and the higher-level circuit breaker intervenes directly, it may expand the scope of the power outage across the entire line. This phenomenon is known as “over-trip.”

A cascading distribution approach enables the Lv Pole Mounted Circuit Breakers circuit breaker closest to the fault point to interrupt power first, thereby isolating the fault locally and reducing the likelihood of higher-level equipment intervention. By precisely setting the operating time and current settings for each level of circuit breaker, a protection logic of “from near to far, from bottom to top” is achieved. Should a short circuit or overload occur at the line terminal, the nearest circuit breaker will trip first, followed by the next higher level, ultimately preserving the busbar or main trunk equipment as the final line of defense.