1. The circuit breaker is in the closed position;

2. The handle is not fully inserted into the push‑in hole on the chassis vehicle.

3. The actuating mechanism has not fully reached the experimental position, preventing the chassis’s locking plate from disengaging from the cabinet body.

1. The circuit breaker is in the unenergized state.

2. The circuit breaker is already in the closed position.

3. A closing‑lockout coil has been selected; the auxiliary power supply is not connected.

4. Inaccurate secondary circuits, or damage to secondary components such as auxiliary switches and closing release devices.

5. The handcart-type circuit breaker has not been fully inserted into the working position or the test position.

6. After installation in conjunction with the cabinet, the circuit breaker frame becomes deformed.

1. The circuit breaker is in the open position.

2. The secondary circuit is inaccurate, or secondary components such as auxiliary switches and trip release mechanisms are damaged.

3. After installation in conjunction with the cabinet, deformation of the circuit breaker frame causes the closing mechanism to reach an over‑dead‑center position.

1. The circuit breaker is in the closed position;

2. The handle is not fully inserted into the push‑in hole on the chassis vehicle.

3. The actuating mechanism has not fully reached the experimental position, preventing the chassis’s locking plate from disengaging from the cabinet body.

1. The circuit breaker is in the unenergized state.

2. The circuit breaker is already in the closed position.

3. A closing‑lockout coil has been selected; the auxiliary power supply is not connected.

4. Inaccurate secondary circuits, or damage to secondary components such as auxiliary switches and closing release devices.

5. The handcart-type circuit breaker has not been fully inserted into the working position or the test position.

6. After installation in conjunction with the cabinet, the circuit breaker frame becomes deformed.

1. The circuit breaker is in the open position.

2. The secondary circuit is inaccurate, or secondary components such as auxiliary switches and trip release mechanisms are damaged.

3. After installation in conjunction with the cabinet, deformation of the circuit breaker frame causes the closing mechanism to reach an over‑dead‑center position.

1. The circuit breaker is in the closed position;

2. The handle is not fully inserted into the push‑in hole on the chassis vehicle.

3. The actuating mechanism has not fully reached the experimental position, preventing the chassis’s locking plate from disengaging from the cabinet body.

1. The circuit breaker is in the unenergized state.

2. The circuit breaker is already in the closed position.

3. A closing‑lockout coil has been selected; the auxiliary power supply is not connected.

4. Inaccurate secondary circuits, or damage to secondary components such as auxiliary switches and closing release devices.

5. The handcart-type circuit breaker has not been fully inserted into the working position or the test position.

6. After installation in conjunction with the cabinet, the circuit breaker frame becomes deformed.

1. The circuit breaker is in the open position.

2. The secondary circuit is inaccurate, or secondary components such as auxiliary switches and trip release mechanisms are damaged.

3. After installation in conjunction with the cabinet, deformation of the circuit breaker frame causes the closing mechanism to reach an over‑dead‑center position.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. Analyze the load and grid operating conditions;

3. If an overload is confirmed, immediately identify and rectify the fault.

4. If the actual operating current does not match the long-time delay trip current, adjust the long-time delay trip setting to reflect the actual operating current, ensuring proper protective coordination.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. Check the setpoints of the smart controller;

4. Inspect the circuit breaker to ensure it is in good condition and confirm that it can be closed and operated.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. If no ground fault is detected, verify that the ground-fault current setting is appropriate and matches the actual protection requirements; if the setting is incorrect, adjust the ground-fault current setting accordingly.

4. Press the reset button to reclose the circuit breaker.

1. Check whether the supply voltage is below 70% of Us;

2. Check whether the undervoltage release and the control unit are malfunctioning.

1. Has the undervoltage release been energized?

2. Check whether the supply voltage is below 70% of Us;

3. Check whether the undervoltage release and the control unit are malfunctioning; if a fault is confirmed, replace the undervoltage release.

1. Verify that the motor control power supply is energized and that the voltage is at least 85% of the rated voltage (Us).

2. Inspect the motor’s energy-storage mechanism for any malfunctions.

1. Verify that the closing solenoid’s supply voltage is ≥85% of Us.

2. If the closing solenoid is defective and fails to engage, it should be replaced.

Trip immediately

Time-delay tripping

1. If a short-circuit current is present in the circuit during closing, the fault should be located and eliminated.

2. Check whether there is an overcurrent in the circuit, and locate and eliminate any faults.

3. The circuit breaker mechanism shall be inspected to ensure it is in good working condition;

4. Verify that the setpoints of the smart controller are appropriate; if not, recalibrate them.

5. Press the reset button to reclose the circuit breaker.

l Cannot trip the circuit breaker remotely.

The circuit breaker cannot be opened by the trip button.

1. Verify that the shunt trip circuit connections are secure and inspect the shunt trip for any faults; if a fault is confirmed, replace the shunt trip.

2. Inspect the operating mechanism for any mechanical malfunctions.

1. Verify that the control power supply voltage of the electric energy storage device is ≥85% of Us, and check for any issues with the circuit connections.

2. Check the motor for any issues;

3. Energy storage system failure.

The smart controller is not powered on.

l The auxiliary power input voltage is abnormal.

The secondary output voltage of the base transformer is abnormal.

The connection between the secondary output of the base transformer and the controller is unreliable.

1. Verify that the smart controller’s power supply is properly connected.

2. Disconnect the power supply to the smart controller, then reconnect it. If the fault persists, the controller may be defective and should be replaced.

The communication cable is not reliably connected to the circuit breaker terminal.

l The A and B ends of the communication line are connected in reverse.

l The communication distance and connection method have issues and do not meet the requirements.

l There is a problem with the circuit breaker’s communication address configuration.

1. Verify that the communication cable is securely connected to the circuit breaker terminals and that there are no wiring errors.

2. Check whether the A and B ends of the communication cable are connected in reverse; if so, correct the wiring.

3. Verify that the communication distance and wiring configuration meet the specified requirements.

4. Verify that the circuit breaker’s communication address is configured correctly and does not conflict with other devices.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. Analyze the load and grid operating conditions;

3. If an overload is confirmed, immediately identify and rectify the fault.

4. If the actual operating current does not match the long-time delay setting current, adjust the long-time delay setting current to reflect the actual operating current, ensuring proper protective coordination.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, immediately locate and eliminate the fault.

3. Check the setpoints of the smart controller;

4. Inspect the circuit breaker to ensure it is in good condition and confirm that it can be closed and operated.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, immediately locate and eliminate the fault.

3. If no ground fault is detected, verify that the ground-fault current setting is appropriate and matches the actual protection requirements; if the setting is incorrect, adjust the ground-fault current setting accordingly.

4. Press the reset button to reclose the circuit breaker.

1. Check whether the supply voltage is below 70% of Us;

2. Check whether the undervoltage release and the control unit are malfunctioning.

1. Has the undervoltage release been energized?

2. Check whether the supply voltage is below 85% of Us;

3. Check whether the undervoltage release and the control unit are malfunctioning; if a fault is confirmed, replace the undervoltage release.

1. Verify that the motor control power supply is connected and that the voltage is at least 85% of the rated voltage (Us).

2. Inspect the motor’s energy-storage mechanism for any malfunctions.

1. Verify that the closing solenoid’s supply voltage is ≥85% of Us.

2. If the closing solenoid is malfunctioning and fails to engage, it should be replaced.

1. If a short-circuit current is present in the circuit during closing, locate and eliminate the fault.

2. Check whether there is an overload current in the circuit, and locate and eliminate any faults.

3. The circuit breaker mechanism shall be inspected to ensure it is in good condition;

4. Verify that the setpoints of the intelligent controller are appropriate; if not, reset them accordingly.

5. Press the reset button to reclose the circuit breaker.

1. Verify that the shunt trip circuit connections are secure and inspect the shunt trip for any faults; if a fault is confirmed, replace the shunt trip.

2. Inspect the operating mechanism for any mechanical malfunctions.

3. Is the voltage of the shunt trip device below 85%?

1. Verify that the control power supply voltage of the electric energy storage device is ≥85% of Us, and check for any issues with the circuit connections.

2. Check the motor for any issues;

3. Energy storage system failure.

l The latch was not held down l The lever was not pulled out

The circuit breaker has not fully reached the “open” position.

The smart controller is not powered on.

The auxiliary power input voltage is abnormal.

The secondary output voltage of the base transformer is abnormal.

The secondary output of the base transformer is not reliably connected to the controller.

1. Verify that the smart controller’s power supply is properly connected.

2. Disconnect the power supply to the smart controller, then reconnect it. If the fault persists, the controller may be defective and should be replaced.

The communication cable is not reliably connected to the circuit breaker terminal.

The polarity of communication lines A and B is reversed.

The communication distance and connection method have issues and do not meet the requirements.

l There is a problem with the circuit breaker’s communication address configuration. l The communication parameter settings are mismatched.

1. Verify that the communication cable is securely connected to the circuit breaker terminals and that there are no wiring errors.

2. Check whether the A and B ends of the communication line are connected in reverse; if so, correct the wiring.

3. Verify that the communication distance and wiring configuration meet the specified requirements.

4. Verify that the circuit breaker’s communication address is configured correctly and does not conflict with other devices.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. Analyze the load and grid operating conditions;

3. If an overload is confirmed, immediately identify and rectify the fault.

4. If the actual operating current does not match the long-time delay setting current, adjust the long-time delay setting current to reflect the actual operating current, ensuring proper protective coordination.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. Check the setpoints of the smart controller;

4. Inspect the circuit breaker to ensure it is in good condition and verify that it can be closed and operated.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. If no ground fault is detected, verify that the ground-fault current setting is appropriate and matches the actual protection requirements; if the setting is incorrect, adjust the ground-fault current setting accordingly.

4. Press the reset button to reclose the circuit breaker.

1. Check whether the supply voltage is below 70% of Us;

2. Check whether the undervoltage release and the control unit are malfunctioning.

1. Has the undervoltage release been energized?

2. Check whether the supply voltage is below 85% of Us;

3. Check whether the undervoltage release and the control unit are malfunctioning; if a fault is confirmed, replace the undervoltage release.

1. Verify that the motor control power supply is connected and that the voltage is at least 85% of the rated voltage (Us).

2. Inspect the motor’s energy-storage mechanism for any malfunctions.

1. Verify that the closing solenoid’s supply voltage is ≥85% of Us.

2. If the closing solenoid is defective and fails to engage, it should be replaced.

Trip immediately

Time-delay tripping

1. If a short-circuit current is present in the circuit during closing, locate and eliminate the fault.

2. Check whether there is an overload current in the circuit, and locate and eliminate any faults.

3. The circuit breaker mechanism shall be inspected to ensure it is in good condition;

4. Verify that the setpoints of the intelligent controller are appropriate; if not, reset them accordingly.

5. Press the reset button to reclose the circuit breaker.

l cannot trip the circuit breaker remotely.

The circuit breaker cannot be opened by the trip button.

1. Verify that the shunt trip circuit connections are secure and inspect the shunt trip for any faults; if a fault is confirmed, replace the shunt trip.

2. Inspect the operating mechanism for any mechanical malfunctions.

3. Is the voltage of the shunt trip device below 85%?

l cannot be manually energized.

l cannot store energy electrically

1. Verify that the control power supply voltage of the electric energy storage device is ≥85% of Us, and check for any issues with the circuit connections.

2. Check the motor for any issues;

3. Energy storage system failure.

l The latch was not held down l The joystick was not pulled out

The circuit breaker has not fully reached the “open” position.

The smart controller is not powered on.

The auxiliary power input voltage is abnormal.

The secondary output voltage of the base transformer is abnormal.

The connection between the secondary output of the base transformer and the controller is unreliable.

1. Verify that the smart controller’s power supply is properly connected.

2. Disconnect the power supply to the smart controller, then reconnect it. If the fault persists, the controller may be defective and should be replaced.

The communication cable is not reliably connected to the circuit breaker terminal.

The polarity of communication lines A and B is reversed.

The communication distance and connection method have issues and do not meet the requirements.

l There is a problem with the circuit breaker’s communication address configuration.

l Communication parameter settings do not match

1. Verify that the communication cable is securely connected to the circuit breaker terminals and that there are no wiring errors.

2. Verify that the A and B ends of the communication cable are not reversed; if they are, correct the wiring.

3. Verify that the communication distance and wiring configuration meet the specified requirements.

4. Verify that the circuit breaker’s communication address is configured correctly and does not conflict with other devices.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. Analyze the load and grid operating conditions;

3. If an overload is confirmed, immediately identify and rectify the fault.

4. If the actual operating current does not match the long-time delay setting current, adjust the long-time delay setting current to reflect the actual operating current, ensuring proper protective coordination.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. Check the setpoints of the smart controller;

4. Inspect the circuit breaker to ensure it is in good condition and confirm that it can be closed and operated.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, promptly locate and rectify the fault.

3. If no ground fault is detected, verify that the ground-fault current setting is appropriate and matches the actual protection requirements; if the setting is incorrect, adjust the ground-fault current setting accordingly.

4. Press the reset button to reclose the circuit breaker.

1. Check whether the supply voltage is below 70% of Us;

2. Check whether the undervoltage release and the control unit are malfunctioning.

1. Has the undervoltage release been energized?

2. Check whether the supply voltage is below 85% of Us;

3. Check whether the undervoltage release and the control unit are malfunctioning; if a fault is confirmed, replace the undervoltage release.

1. Verify that the motor control power supply is connected and that the voltage is at least 85% of the rated voltage (Us).

2. Inspect the motor’s energy-storage mechanism for any malfunctions.

1. Verify that the closing solenoid’s supply voltage is ≥85% of Us.

2. If the closing solenoid is defective and fails to engage, it should be replaced.

1. If a short-circuit current is present in the circuit during closing, locate and eliminate the fault.

2. Check whether there is an overcurrent in the circuit, and locate and eliminate any faults.

3. The circuit breaker mechanism shall be inspected to ensure it is in good condition;

4. Verify that the setpoints of the intelligent controller are appropriate; if not, reset them accordingly. 5. Press the reset button to reclose the circuit breaker.

l cannot trip the circuit breaker remotely.

The circuit breaker cannot be opened by the trip button.

1. Verify that the shunt trip circuit connections are secure and inspect the shunt trip for any faults; if a fault is confirmed, replace the shunt trip.

2. Inspect the operating mechanism for any mechanical malfunctions.

3. Is the voltage of the shunt trip device below 85%?

l cannot be manually energized.

L cannot store energy electrically.

1. Verify that the control power supply voltage of the electric energy storage device is ≥85% of Us, and inspect the circuit connections for any issues.

2. Check the motor for any issues;

3. Energy storage system failure.

lDid not hold the latch

The joystick has not been pulled out.

The circuit breaker has not fully reached the “open” position.

The smart controller is not powered on.

The auxiliary power input voltage is abnormal.

The secondary output voltage of the base transformer is abnormal.

The secondary output of the base transformer is not reliably connected to the controller.

1. Verify that the smart controller’s power supply is properly connected.

2. Disconnect the power supply to the smart controller, then reconnect it. If the fault persists, the controller may be defective and should be replaced.

The communication cable is not reliably connected to the circuit breaker terminal.

The polarity of communication lines A and B is reversed.

The communication distance and connection method have issues and do not meet the requirements.

l There is a problem with the circuit breaker’s communication address configuration.

l Communication parameter settings do not match

1. Verify that the communication cable is securely connected to the circuit breaker terminals and that there are no wiring errors.

2. Verify that the A and B ends of the communication cable are not reversed; if they are, correct the wiring.

3. Verify that the communication distance and wiring configuration meet the specified requirements.

4. Verify that the circuit breaker’s communication address is configured correctly and does not conflict with other devices.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. Analyze the load and grid operating conditions;

3. If an overload is confirmed, immediately identify and rectify the fault.

4. If the actual operating current does not match the long-time delay setting current, adjust the long-time delay setting current to reflect the actual operating current, ensuring proper protective coordination.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, immediately locate and eliminate the fault.

3. Check the setpoints of the smart controller;

4. Inspect the circuit breaker to ensure it is in good condition and confirm that it can be closed and operated.

5. Press the reset button to reclose the circuit breaker.

1. On the intelligent controller, verify the breaking current value and the operating time.

2. If a short circuit is confirmed, immediately locate and eliminate the fault.

3. If no ground fault is detected, verify that the ground-fault current setting is appropriate and matches the actual protection requirements; if the setting is incorrect, adjust the ground-fault current setting accordingly.

4. Press the reset button to reclose the circuit breaker.

1. Check whether the supply voltage is below 70% of Us;

2. Check whether the undervoltage release and the control unit are malfunctioning.

1. Has the undervoltage release been energized?

2. Check whether the supply voltage is below 85% of Us;

3. Check whether the undervoltage release and the control unit are malfunctioning; if a fault is confirmed, replace the undervoltage release.

1. Verify that the motor control power supply is connected and that the voltage is at least 85% of the rated voltage (Us).

2. Inspect the motor’s energy‑storage mechanism for any malfunctions.

1. Verify that the closing solenoid’s supply voltage is ≥85% of Us.

2. If the closing solenoid is defective and fails to engage, it should be replaced.

1. If a short-circuit current is present in the circuit during closing, locate and eliminate the fault.

2. Check whether there is an overload current in the circuit, and locate and eliminate any faults.

3. The circuit breaker mechanism shall be inspected to ensure it is in good condition;

4. Verify that the setpoints of the intelligent controller are appropriate; if not, reset them accordingly.

5. Press the reset button to reclose the circuit breaker.

1. Verify that the shunt trip circuit connections are secure and inspect the shunt trip for any faults; if a fault is confirmed, replace the shunt trip.

2. Inspect the operating mechanism for any mechanical malfunctions.

3. Is the shunt trip coil voltage below 85%?

1. Verify that the control power supply voltage of the electric energy storage device is ≥85% of Us, and check for any issues with the circuit connections.

2. Check the motor for any issues; 3. Fault in the energy-storage mechanism.

The smart controller is not powered on.

The auxiliary power input voltage is abnormal.

The secondary output voltage of the base transformer is abnormal.

The secondary output of the base transformer is not reliably connected to the controller.

1. Verify that the smart controller’s power supply is properly connected.

2. Disconnect the power supply to the smart controller, then reconnect it. If the fault persists, the controller may be defective and should be replaced.

The communication cable is not reliably connected to the circuit breaker terminal.

l The A and B ends of the communication line are connected in reverse. l There are issues with the communication distance and connection method that do not meet the requirements.

l There is a problem with the circuit breaker’s communication address configuration.

l Communication parameter settings do not match

1. Verify that the communication cable is securely connected to the circuit breaker terminals and that there are no wiring errors.

2. Check whether the A and B ends of the communication cable are connected in reverse; if so, correct the wiring.

3. Verify that the communication distance and wiring configuration meet the specified requirements.

4. Verify that the circuit breaker’s communication address is configured correctly and does not conflict with other devices.

1) Is the connected load a motor that requires direct-on-line starting, and what is the inrush current?

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting current.

1) Determine the motor terminal voltage (P = IUcos Φ);

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting current.

1) Inspect the mechanical condition of the motor (and its load).

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting current.

1) Determine the cross-sectional area and length of the connecting cable or copper busbar.

2) Select the appropriate cross-sectional area of connecting cables or busbars according to the sample specifications.

3) Select the appropriate length of connecting cables or busbars.

1) Verify that the connections between the circuit breaker and the cable and copper busbar are secure.

2) Tighten the connection screws between the circuit breaker and the cable and copper busbar.

A short-circuit overreach trip occurs during the operation of a circuit breaker. There may be two possible scenarios:

1) The molded-case circuit breaker does not trip, while the universal-type circuit breaker trips;

2) The low-voltage circuit breaker (including molded-case circuit breakers and universal-type circuit breakers) does not trip, while the high-voltage protective device trips.

1) Inspect the circuit breaker’s status on-site; if no tripping‑lockout phenomenon is observed, the product shall be deemed to be in normal condition.

2) Test characteristics to determine whether the circuit breaker is qualified or not;

3) Select circuit breakers appropriately.

1) Is the connected load a motor that requires direct-on-line starting, and what is its starting current?

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting.

1) Determine the motor terminal voltage (P = IUcos Φ);

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting current.

1) Inspect the mechanical condition of the motor (and its load).

2) Appropriately determine the circuit breaker’s rated current and the multiple of the instantaneous trip setting current.

1) Determine the cross-sectional area and length of the connecting cable or copper busbar.

2) Select the appropriate cross-sectional area of connecting cables or busbars according to the sample specifications.

3) Select the appropriate length of connecting cables or busbars.

1) Verify that the connections between the circuit breaker and the cable and copper busbar are secure.

2) Tighten the connection screws between the circuit breaker and the cable or copper busbar.

1) Determine the contact condition of the plug;

2) Reliable connection plug.

A short-circuit overreach trip occurs during the operation of a circuit breaker. There may be two possible scenarios:

1) The molded-case circuit breaker does not trip, while the universal-type circuit breaker trips;

2) The low-voltage circuit breaker (including molded-case circuit breakers and universal-type circuit breakers) does not trip, while the high-voltage protective device trips.

1) Inspect the circuit breaker’s status on-site; if no tripping failure is observed, the product shall be deemed to be in normal condition.

2) Test the characteristics to determine whether the circuit breaker is qualified or not;

3) Select circuit breakers appropriately.