Common Causes And Solutions For Malfunction And Refusal Of Electronic Leakage Circuit Breakers

The leakage protector plays an important role in personal safety, equipment protection and prevention of electrical fires. However, due to improper installation and use, the leakage protector cannot operate normally, malfunctions or refuses to operate. The so-called malfunction is the phenomenon that the leakage protector operates when there is no leakage fault in the line. On the contrary, when there is a leakage fault in the line, the leakage protector should operate but does not operate, which is called refusal to operate.
The following are the more common cases of malfunction:
(1) Three-pole leakage circuit breaker is used in three-phase four-wire circuits. Since the normal operating current in the neutral line does not pass through the zero-sequence current transformer, the circuit breaker will operate as soon as the single-phase load is started.
Solution: A three-phase four-wire circuit must use a three-phase four-wire leakage circuit breaker.
(2) The neutral line on the load side of the leakage circuit breaker is grounded, which will cause the normal operating current to be diverted to the ground through the grounding point, causing the leakage circuit breaker to malfunction.
Solution: Connect the neutral line to the neutral line on the power supply side of the leakage circuit breaker.
(3) The wires on the load side of the leakage circuit breaker are long, and some are laid close to the ground, which has a large capacitance to the ground. In this way, there is a large capacitance current to the ground, which may cause the circuit breaker to malfunction.
Solution: Install the leakage protector as close to the load as possible, or choose a circuit breaker with a slightly larger leakage action.
The most common reason for refusal to operate is improper wiring, which mainly includes the following two situations
(1) Using a three-pole leakage circuit breaker in a single-phase circuit, or a four-pole leakage circuit breaker in a three-phase circuit, and connecting the ground wire of the equipment as one phase to the leakage circuit breaker.
(2) If the neutral grounding point on the load side is shunted, the comprehensive result will make the current difference smaller. If this value is less than the rated leakage action value of the leakage circuit breaker, it will also cause refusal to operate.