This is the most commonly used tripping scheme. The protective relay (PR) contact is arranged directly to trip the circuit breaker and it simultaneously energises an auxiliary unit X which then reinforces the contact that is energising the trip coil. The scheme is shown in Figure. Frequent tripping of your distribution box is a critical alarm, not just an annoyance. For facility managers, electricians, and project owners operating overseas—from industrial plants in the Middle East to solar farms in Southeast Asia—these unexpected shutdowns mean costly downtime, safety risks. Very often, the lowest-level circuit breaker does not trip, but the upstream (higher-level) one does! This causes a large-scale power outage! Why does this happen? Today, we'll discuss this issue. This operation also involves considerable manual intervention which therefore necessitates the fulfilment of safety requirements laid down in. ng or immediately following out-of-section faults. There are two classifications of sympathetic trips: those which occur due to delayed voltage recovery conditions, and those which. Abstract: Sympathetic tripping is a common challenge that affects the proper operation of the earth fault (EF) relays in distribution networks.