When the transmission distance exceeds 100 meters, voltage drop becomes more important than current; voltage drop thus becomes the main factor determining the cable diameter

In power transmission, the selection of cable diameter generally takes into account two main factors: current-carrying capacity and voltage drop. The current-carrying capacity refers to the maximum current that a cable can transmit safely; excessive current can cause the cable to overheat and even burn out. Voltage drop refers to the voltage reduction that occurs during current transmission through a cable due to the cable’s resistance, and this affects the voltage level at the load end. For short-distance power transmission (such as from a few meters to several dozen meters), the voltage drop is usually negligible due to the relatively low resistance of the cables. Therefore, in this case, the selection of the cable is primarily based on its current-carrying capacity. However, when the transmission distance increases to 100 meters or even more, the resistance of the cable becomes relatively high, and as a result, the voltage drop also increases. In long-distance transmission, if the cable diameter is not selected appropriately, it can result in significant voltage drops, which in turn lead to insufficient voltage at the load end and affect the proper operation of the equipment. For this reason, in the case of long-distance power transmission (over 100 meters), it is indeed necessary to consider using a smaller voltage drop when determining the cable diameter, in order to ensure efficient power transmission and stability at the load end. At this point, even if the cable can handle a high current, if the voltage drop is too large, it may be necessary to use a thicker cable in order to reduce the voltage drop and thus ensure efficient transmission as well as the proper operation of the connected devices. .