确定配电箱的额定电流，需要综合考量所连接设备的用电需求、线路承载能力及使用场景，通过科学计算与合理预留，确保配电箱既能满足正常运行，又能应对突发情况，保障用电。

　　To determine the rated current of the distribution box, it is necessary to comprehensively consider the power demand of the connected equipment, the carrying capacity of the line, and the usage scenario. Through scientific calculation and reasonable reservation, it is ensured that the distribution box can meet both normal operation and emergency situations, ensuring electrical safety. 

　　，需精准统计所有接入设备的总电流。配电箱的额定电流必须大于或等于所连接设备的总工作电流，这是基本的原则。计算总电流时，需先明确各设备的额定功率，再根据公式 “电流 = 功率 ÷ 电压”（单相设备电压取 220V，三相设备取 380V）换算出单台设备的额定电流。例如，一台功率为 2.2kW 的单相电机，其额定电流约为 10A；一台 5.5kW 的三相水泵，额定电流约为 11A。将所有设备的额定电流相加，得到总电流值，但需注意，部分设备（如空调、电焊机）启动时会产生冲击电流，需将其启动电流纳入考量 —— 通常电机类设备的启动电流为额定电流的 5-7 倍，可按总电流的 1.2-1.5 倍作为参考，避免配电箱因启动瞬间过载而跳闸。

　　Firstly, it is necessary to accurately calculate the total current of all connected devices. The rated current of the distribution box must be greater than or equal to the total operating current of the connected equipment, which is the most basic principle. When calculating the total current, it is necessary to first clarify the rated power of each device, and then convert the rated current of a single device according to the formula "current=power ÷ voltage" (220V for single-phase equipment and 380V for three-phase equipment). For example, a single-phase motor with a power of 2.2kW has a rated current of about 10A, and a three-phase water pump with a power of 5.5kW has a rated current of about 11A. Adding up the rated currents of all devices gives the total current value, but it should be noted that some devices (such as air conditioners and welding machines) may generate surge currents when starting, and their starting currents need to be taken into account - usually the starting current of motor equipment is 5-7 times the rated current, and 1.2-1.5 times the total current can be used as a reference to avoid tripping the distribution box due to instantaneous overload during starting. 

　　其次，需结合线路的载流量进行匹配。配电箱的额定电流不能超过进线电缆的载流量，否则会导致线路过热，存在火灾风险。不同规格的电缆（如铜芯线、铝芯线）在不同敷设环境（如穿管、明敷、高温环境）下的载流量存在差异，例如 10 平方毫米的铜芯电缆在明敷时载流量约为 65A，穿管敷设时可能降 50A。选择配电箱额定电流时，需参考电缆的实际载流量，确保两者匹配，若电缆载流量小于设备总电流，需先更换更粗的电缆，再确定配电箱额定电流，形成 “设备 - 配电箱 - 线路” 的电流适配闭环。

　　Secondly, it is necessary to match the current carrying capacity of the line. The rated current of the distribution box cannot exceed the maximum current carrying capacity of the incoming cable, otherwise it may cause overheating of the line and pose a fire risk. The current carrying capacity of cables of different specifications (such as copper core wire and aluminum core wire) varies in different laying environments (such as conduit, exposed laying, and high temperature environment). For example, a 10 square millimeter copper core cable has a current carrying capacity of about 65A when exposed, and may drop to 50A when laid in conduit. When selecting the rated current of the distribution box, it is necessary to refer to the actual current carrying capacity of the cable to ensure that they match. If the current carrying capacity of the cable is less than the total current of the equipment, a thicker cable should be replaced first, and then the rated current of the distribution box should be determined to form a current adaptation loop of "equipment distribution box line". 

　　使用场景与工作方式也会影响额定电流的确定。对于长期连续运行的配电箱（如工厂生产线的动力配电箱），由于设备持续工作，发热积累明显，额定电流需在总电流的基础上增加 20%-30% 的余量，以应对长时间运行带来的负荷波动。而对于间歇性工作的配电箱（如建筑工地的临时配电箱），设备并非同时启动，可适当降低余量，通常按总电流的 1.1-1.2 倍计算即可。此外，若配电箱所在环境温度较高（如夏季户外、靠近热源），或存在粉尘、潮湿等情况，需进一步提高额定电流的预留比例，因为高温会降低电器元件的载流能力，恶劣环境可能加速设备老化，预留足够余量能提升配电箱的耐用性。

　　The usage scenario and working mode can also affect the determination of rated current. For distribution boxes that operate continuously for a long time (such as power distribution boxes on factory production lines), due to the continuous operation of the equipment and significant heat accumulation, the rated current needs to be increased by 20% -30% margin on the basis of the total current to cope with load fluctuations caused by long-term operation. For distribution boxes that work intermittently (such as temporary distribution boxes on construction sites), the equipment does not start at the same time, and the margin can be appropriately reduced, usually calculated at 1.1-1.2 times the total current. In addition, if the temperature of the environment where the distribution box is located is high (such as outdoors in summer, near heat sources), or there is dust, humidity, etc., it is necessary to further increase the reserve ratio of the rated current, because high temperature will reduce the current carrying capacity of electrical components, and harsh environments may accelerate equipment aging. Adequate margin can be reserved to improve the durability of the distribution box. 

　　电器元件的选型对额定电流起决定性作用。配电箱内部的断路器、隔离开关等核心元件，其额定电流需与配电箱的额定电流保持一致，例如额定电流为 100A 的配电箱，应配备 100A 的主断路器。断路器的脱扣电流设置也需合理，瞬时脱扣电流通常为额定电流的 5-10 倍，既能在设备启动时避开冲击电流，又能在发生短路故障时快速跳闸，保护线路和设备。同时，元件的与质量需可靠，避免因元件过载能力不足导致额定电流 “虚标”，实际使用中需通过正规渠道采购符合标准的元件，确保其承载能力与标称值一致。

　　The selection of electrical components plays a decisive role in determining the rated current. The rated current of core components such as circuit breakers and isolating switches inside the distribution box should be consistent with the rated current of the distribution box. For example, a distribution box with a rated current of 100A should be equipped with a 100A main circuit breaker. The tripping current setting of the circuit breaker should also be reasonable. The instantaneous tripping current is usually 5-10 times the rated current, which can avoid surge current during equipment startup and quickly trip in case of short circuit faults, protecting the circuit and equipment. At the same time, the brand and quality of the components need to be reliable to avoid "false labeling" of the rated current due to insufficient overload capacity of the components. In actual use, components that meet national standards should be purchased through formal channels to ensure that their load-bearing capacity is consistent with the nominal value. 

　　，需参考相关规范与标准。电气设计需遵循电气安装规范，不同场所的配电箱有不同的要求 —— 住宅配电箱的额定电流通常根据户型大小确定，小户型多为 63A，大户型可达 100A；商业场所（如、办公楼）的配电箱需根据租赁商户的用电需求分段设计，总进线配电箱额定电流可能达到 250A 以上。在计算过程中，可借助电气设计手册中的数据图表，结合实际情况调整，必要时咨询电气人员，确保额定电流的确定既符合标准，又能满足实际使用需求。

　　Finally, it is necessary to refer to relevant specifications and standards. Electrical design must comply with electrical installation standards, and distribution boxes in different locations have different requirements - the rated current of residential distribution boxes is usually determined based on the size of the unit, with small units typically rated at 63A and large units up to 100A; distribution boxes in commercial areas (such as shopping malls and office buildings) need to be designed in sections according to the electricity needs of tenants, and the rated current of the total incoming distribution box may reach 250A or more. During the calculation process, data charts in the electrical design manual can be used to adjust according to the actual situation. If necessary, professional electrical personnel can be consulted to ensure that the determination of the rated current meets both safety standards and actual usage needs.