Reasons for electrical failure of distribution box

1 Faults caused by the influence of ambient temperature on low-voltage electrical appliances

The low-voltage electrical appliances in the distribution box are composed of fuses, AC contactors, residual current action protectors, capacitors and meters. These low-voltage electrical appliances are designed and manufactured in accordance with GB1497 "Basic Standards for Low-Voltage Electrical Appliances", and their normal working conditions are specified accordingly: the upper limit of ambient air temperature does not exceed 40 ℃; the average value of ambient air temperature for 24 hours does not exceed 35 ℃ ; The lower limit of ambient air temperature is not lower than -5℃ or -25℃.

In some areas, the distribution box runs outdoors, and it is not only exposed to direct sunlight to generate high temperature, but also generates heat during operation. Therefore, in the high summer season, the temperature in the box will reach above 60 ℃. The temperature at this time greatly exceeds the specified ambient temperature of these electrical appliances, so failures caused by overheating of electrical components in the distribution box will occur.

2 Failures caused by product quality

If the manufacturer of the distribution box you purchased does not have strict requirements on product quality, it may cause some products to fail soon after they are put into operation. For example, some types of AC contactors cannot run because the closing coil of the contactor is burned out soon after the distribution box is put into operation.

3 Faults caused by improper selection of electrical appliances in the distribution box

Workers do not choose the capacity of the AC contactor very properly, and install AC contactors of the same capacity for different outgoing circuits. The workers did not consider the imbalance of the three-phase load, so they failed to select the correct AC contactor, which led to the burnout of the AC contactor during operation in the high temperature season in summer.