What is the Current Rating of the Switch for Container Houses?

The specific current rating (in amperes, A) of the switch for container houses cannot be directly determined and needs to be calculated based on the actual situation. The following provides a detailed explanation from the perspectives of calculation methods and considerations:

Calculation Method

If the load inside the container house is a three-phase balanced load, the current can be calculated using the formula I = P / (√3×U×cosφ). Here, I represents the current (in amperes, A), P represents the power (in watts, W), U represents the line voltage (in China, the line voltage for three-phase power is typically 380V), and cosφ represents the power factor. Different types of loads have different power factors. For example, the power factor of resistive loads (such as electric stoves) is close to 1, while the power factor of inductive loads (such as electric motors) is generally between 0.6 and 0.9. Using this formula, you can preliminarily estimate the required current size based on the total power of the electrical equipment in the house.

Considerations

• Simultaneity Factor Correction: In actual power usage, not all electrical equipment will operate at full load simultaneously, so the simultaneity factor needs to be considered. In industrial settings, the simultaneity factor generally ranges from 0.7 to 0.9; in residential settings, it generally ranges from 0.5 to 0.7. For example, if a container house has various electrical equipment with a total power of 10kW and it is a residential setting with a simultaneity factor of 0.6, then when calculating the current, you can use a power of 6kW.
• Cable Current-Carrying Capacity: The rated current of the switch must not exceed the current-carrying capacity of the cable; otherwise, it will cause the cable to overheat and pose safety hazards. The current-carrying capacity of a cable is related to factors such as the cable's material, cross-sectional area, and laying method. For example, cables of the same material and cross-sectional area have a higher current-carrying capacity when laid openly compared to when laid concealed. When selecting a switch, you need to first determine the current-carrying capacity of the cable and then ensure that the rated current of the switch is less than or equal to the cable's current-carrying capacity.
• Power Usage Scenario and Load Type: Different power usage scenarios and load types have different requirements for switches. In industrial settings, where electrical equipment has high power and is mostly inductive loads, a switch with a higher rated current needs to be selected; in residential settings, where electrical equipment has relatively low power and is mostly resistive loads, a switch with a lower rated current can be chosen.