The top three possible reasons for a small power distribution unit trip are:

Overload: When the load in the circuit exceeds the rated capacity of the small power distribution unit or circuit, the current will increase, resulting in overload. This can be caused by using a lot of electrical equipment at the same time or plugging in high-wattage devices. An overload triggers a protective device that trips the small power distribution unit to prevent overheating or damage to the circuit.

Short Circuit: When a short circuit occurs between two conductors in a circuit, the current increases suddenly, causing the circuit to short. This can be caused by broken wires, internal malfunctions in electrical equipment, or damaged circuit components. A short circuit will cause excessive current flow, triggering the protection device to trip the small power distribution unit to prevent fire or equipment damage.

Earth leakage: Earth leakage occurs when live parts in a circuit come into contact with a grounded body or ground line. This can be caused by damaged wiring insulation, faulty equipment, or a faulty ground connection. Earth leakage can cause current to pass through a human body or other conductive objects, creating a shock hazard. In order to protect personal safety, the protection device will trip the small power distribution unit to cut off the power supply.

These are common causes of electrical box tripping, and regular inspection and maintenance of circuits can reduce the occurrence of these problems. But if there are frequent trips or other safety issues, they should be diagnosed and repaired by a professional electrician.