What causes the submersible pump to trip when powered on
1. Electrical malfunction
Short circuit: Water ingress into the internal coils, cables, or junction boxes of the pump body can cause a short circuit. Use a multi-meter to measure the winding resistance (normally several ohms to tens of ohms, if it is close to zero, it is a short circuit).
Insulation damage: Cable damage or motor moisture causing insulation degradation (measured with a meg-ohmmeter, insulation resistance should be ≥ 0.5M Ω).
Wiring error: The phase wire contacts the housing or the neutral/live wire is reversed (check if the wiring terminals are loose or oxidized).
2. Mechanical failure
Impeller stuck: Foreign objects or damaged bearings inside the pump cause the motor to stall (manually rotate the impeller to check for flexibility).
Mechanical seal leakage: Water seeps into the motor chamber, causing a short circuit (check if the seal is intact).
3. Protection device issues
Overload protection: The current exceeds the rated value of the circuit breaker (check the matching between the pump power and the circuit breaker, such as a 1.5kW pump with a 10A circuit breaker).
Leakage protector mis-operation: Line leakage or high sensitivity of the protector (whether it still trips after disconnecting the load test).
4. Other reasons
Voltage abnormality: High/low voltage causes a sudden change in current (use a multi-meter to measure if the power supply voltage is within ± 10% of the rated value).
Cable malfunction: underwater cable damage or water ingress at the joint (segmented inspection of cable insulation).
Troubleshooting steps
Power outage detection:
Remove the pump power cord and use a multi-meter to measure whether the three-phase winding resistance is balanced and whether the ground resistance is normal (>0.5M Ω).
Check for any damage to the cable (shake the meter to measure insulation).
Empty load test:
Disconnect the mechanical load of the pump and conduct a separate power on test run (if normal, mechanical failure).
Substitution method:
Replace the circuit breaker or leakage protector of the same model to eliminate the fault of the protective device.
Handling suggestions
Electrical malfunction: Dry the motor or replace the winding/cable.
Mechanical failure: Clean foreign objects, replace bearings or seals.
Protection issue: Adjust the rated current of the circuit breaker or replace the leakage protection.
If it is difficult to troubleshoot on your own, it is recommended to contact a professional electrician or pump manufacturer for after-sales service.
Attention: Be sure to cut off the power before operation to avoid the risk of electric shock!
