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Mobile WebSiteSimply speaking of how much current a 10 square copper wire can withstand, we don't need to calculate it by ourselves, and it is difficult to calculate it under normal conditions. Now it is very convenient to find information, whether it is online or books can be easily found. What really needs to be calculated is that at this current, the voltage drop generated by the length of the wire can be accepted. Because there is not a simple linear relationship between the wire cross-sectional area and the maximum current allowed. For example, the current of 1mm2 copper wire is 13A, while 10mm2 does not reach 130 but only 55A, and 95mm2 is only 240A. The higher the current, the smaller the current per unit area. The left side of the figure below shows the relationship between current and cross-sectional area. It can be clearly seen that there is a curve between the two.
In actual work, 10mm2 copper wire can not pass 55A current under any circumstances (overhead, buried, and number of strands will also affect). For example, when we use 380v power supply, if the allowable voltage drop is 10%, the maximum length of the wire must not exceed 406m, otherwise the current must be reduced or the cross-sectional area must be increased. This is also the reason why there are many buried cables of street lamps with a current of only 20 or 30 amperes, but cables above 25mm2 are used. Therefore, the current cannot be determined only based on the cross-sectional area, but the ultimate goal is to ensure that the load works normally.
