Loose connections or worn out contact surfaces are the root causes of electrical system conduction troubles. According to the electronic design rules, every 10°C rise in temperature reduces the average. Although the weather is not yet hot, different types of faults have occurred to the residual current operated protector in the distribution box, such as: (1) fault of residual current operated protector; (2) fault of converter contactor; (3) fault of metering energy meter; (4) fault caused by. Outdoor low-voltage power distribution boxes (hereinafter referred to as "distribution boxes") are low-voltage distribution equipment used in 380/220V power supply systems to receive and distribute electrical energy. This causes thermal runaway, which damages the insulating material at high. Think of the last time you touched a device that was too hot – that discomfort is multiplied a thousandfold inside a distribution box. Insulation materials become brittle, metals fatigue, and connections loosen. In extreme cases. standing about how to establish the condition of the connection once a ther-mal anomaly has been found. Infrared thermography, however, only.