Why Does My Over-under Voltage Protector Trip Repeatedly？

Frequent tripping of the resettable overvoltage and undervoltage protector is commonly caused by sensed voltage anomalies, internal device faults, or issues within the household wiring system.

Common Causes of Tripping

1. Grid voltage fluctuations

This is the most common external cause. Electrical load changes can cause voltage fluctuations—e.g., high evening grid demand often raises voltage, triggering protection.

2. Protector malfunction or improper settings

• Incorrect parameter settings: The recovery voltage threshold on older models may be configured too low for current grid standards. During off-peak periods, the grid voltage rises slightly, and it may exceed the protector's recovery value, preventing it from reclosing or causing it to trip repeatedly.

• Product quality or installation issues: The use of substandard protectors or improperly tightened terminal screws during installation can result in poor electrical contact. This may lead to frequent tripping or even damage to the device.

• Lack of overload and short-circuit protection: The resettable overvoltage and underVoltage Protector itself does not provide overload and short-circuit protection. If no circuit breaker is connected in series upstream of the protector, a short circuit or severe overload in the line may result in a large current that can directly damage the protector.

3. Household wiring or appliance issues

• Loose neutral connection: This is a very common failure condition. If the main neutral conductor in the household is loosely connected, it can cause severe voltage imbalance, leading the protector to trip repeatedly or even fail to reclose.

• Effects of high-power appliances: When multiple high-power appliances, such as air conditioners, are started simultaneously, the inrush current can be extremely large. This may cause a transient voltage drop, which can activate the protection.

How to Diagnose the Issues？

• Identify tripping patterns: Note the time and date of each tripping occurrence or the operation of a particular high-wattage appliance. If so, the issue is likely related to grid voltage fluctuations.

• Check the indicator light status: 

  • Rapid red flashing indicates overvoltage.

  • Slow red flashing indicates undervoltage.

  • Red illumination indicates phase loss or internal fault.

• Wiring inspection: Only perform inspections if you are qualified. Check that all terminal screws are properly tightened and verify that the live wire and neutral wire are connected to the correct terminals. Confirm that a MCB is installed in series upstream of the protector.

• Protector replacement: If both grid voltage and household wiring have been verified as normal, the protector itself is likely the cause. Replacement of the protector is advised. Consider choosing a model with a slightly higher rated current to provide additional operating margin.