Circuit breaker failure may not necessarily be a problem with the product itself, but may also be caused by improper operation. Today, Weikewei Technology has summarized the faults caused by improper operation of circuit breakers for everyone.

（液压电磁式断路器）

1. Caused by overvoltage.

If the frequency of lightning induced overvoltage and operating overvoltage in the circuit is high, the line's capacitance to ground is small, and the instantaneous leakage current to ground is large, it often causes residual current circuit breaker misoperation. At this time, a residual current operated circuit breaker with delay or impulse voltage non action can be selected, or a resistance capacitance absorption circuit can be installed between the contacts to suppress overvoltage, or an overvoltage absorption device can be installed in the circuit.

2. Electromagnetic interference.

If there are magnetic equipment or high-power electrical equipment nearby for starting and stopping, the installation position of the residual current operated circuit breaker should be adjusted to stay away from such electrical equipment.

3. Circulation influence.

If two transformers are running in parallel and have their own grounding, the impedance of the two transformers cannot be completely equal, which will generate circulating current in the grounding wire and cause residual current to operate the circuit breaker. Therefore, the two transformers running in parallel should be grounded together. In addition, if the same transformer supplies power to the same load through two parallel circuits, the currents in the two circuits cannot be exactly the same, and circulating currents may also occur. Therefore, the two circuits should be operated separately.

4. The insulation resistance of the working neutral wire decreases.

When the insulation resistance of the working neutral line decreases, if the three-phase load is unbalanced, a relatively large working current will appear on the neutral line and flow through the ground to other branches, resulting in leakage current on each residual current operated circuit breaker, causing the residual current operated circuit breaker to malfunction.

5. Improper grounding.

If the neutral wire is repeatedly grounded, it will cause the residual current to trigger the misoperation of the circuit breaker.

6. Overload or short circuit.

If the residual current operated circuit breaker has both short-circuit protection and overcurrent protection, misoperation may occur when the setting current of the overcurrent protection release is not appropriate. At this time, the setting overcurrent value should be adjusted.

7. Three pole residual current operated circuit breaker, 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, as soon as the single-phase load is started, the residual current will activate the circuit breaker. Three phase four wire residual current operated circuit breakers should be selected.

8. The grounding of the neutral wire on the load side of the residual current operated circuit breaker will cause the normal operating current to be diverted into the ground through the grounding point, resulting in the misoperation of the residual current operated circuit breaker. The neutral wire should be connected to the neutral wire end on the power side of the residual current operated circuit breaker.

9. The wires on the load side of residual current operated circuit breakers are relatively long, and some are laid closely to the ground, resulting in a large capacitance to ground. This may cause a large capacitance current to ground, which may lead to misoperation of residual current operated circuit breakers. Install residual current operated circuit breakers as close to the load as possible, or choose residual current operated circuit breakers with slightly larger leakage current.

10. Choosing too small a leakage current can cause misoperation.

When selecting the leakage current, it should be greater than 2-4 times the normal leakage current in the circuit. The normal leakage current of electronic devices is relatively high, and the number of electronic devices carried in each circuit should not be too many. The total leakage current should be less than the rated non operating current of the residual current operated circuit breaker. For example, if the leakage current of a desktop computer is 3-4mA, the number of computers connected to the 30mA residual current operated circuit breaker circuit should not exceed 5.

Have you understood the circuit breaker faults caused by improper operation and the solutions mentioned above.