🔌 导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG)

使用说明与常见问题How-to & FAQ

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」是什么？What is the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) tool?

按允许电压降计算所需导线截面积：输入电流、单程长度、电压和允许压降百分比，选择铜或铝、直流/单相或三相，得到最小截面积、推荐的标准规格（mm²）和近似 AWG，以及选用该规格时的实际压降。载流量还取决于敷设方式，请同时核对规范。本地处理。Find the wire cross-section needed for an allowed voltage drop: enter current, one-way length, voltage and allowed drop %, pick copper or aluminium and DC/single phase or three phase, and get the minimum area, the recommended standard size (mm²), the nearest AWG and the actual drop with that size. Ampacity also depends on installation, so check your wiring code too. Processed locally.

如何使用「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」？How do I use the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) tool?

在「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」中，填写「电流（A）」、「单程长度（m）」、「电压（V）」、「允许压降（%）」、「材质」等参数，结果会随输入实时计算并显示在下方。In the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG): Fill in "Current (A)", "One-way length (m)", "Voltage (V)", "Allowed voltage drop (%)", "Material"; results are recalculated instantly as you type.

为什么长度要乘以 2？Why is the length doubled?

直流和单相回路中电流要经过去线和回线，所以导线总长是单程长度的 2 倍；三相平衡负载用 √3 代替 2。In DC and single-phase circuits the current flows out and back, so the conductor length is twice the one-way length; for a balanced three-phase load √3 replaces 2.

允许压降一般取多少？What voltage drop is usually allowed?

很多规范建议末端用电设备压降不超过 3%，从电源到末端总计不超过 5%。具体以当地电气规范为准。Many codes recommend no more than 3% drop to the final load and 5% in total from the supply. Follow your local electrical code.

能举个计算实例吗？Can you show a worked example?

例如在「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」中填 电流（A） = 20，单程长度（m） = 30，电压（V） = 230，允许压降（%） = 3，材质 = 铜，系统 = 直流或单相，结果区显示：最小截面积：2.9913 mm²；推荐标准规格：4 mm²；近似 AWG：AWG 12 (3.31 mm²)；选用后的压降：5.16 V (2.243%)；允许压降：6.9 V；ℹ A = 2 × ρ × L × I ÷ ΔV，ρ（20 °C）铜 0.0172、铝 0.0282 Ω·mm²/m；这里只按压降计算，还须满足载流量和保护要求For example, entering Current (A) = 20, One-way length (m) = 30, Voltage (V) = 230, Allowed voltage drop (%) = 3, Material = Copper, System = DC or single phase in the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) gives: Minimum cross-section: 2.9913 mm²; Recommended standard size: 4 mm²; Nearest AWG: AWG 12 (3.31 mm²); Drop with that size: 5.16 V (2.243%); Allowed drop: 6.9 V; ℹ A = 2 × ρ × L × I ÷ ΔV with ρ (20 °C) copper 0.0172, aluminium 0.0282 Ω·mm²/m; this sizes for…

哪些输入会被检查？Which inputs are validated?

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」会检查这些输入——「电流（A）」：必须填写，须大于 0且不大于 5,000；「单程长度（m）」：必须填写，须大于 0且不大于 100,000；「电压（V）」：必须填写，须大于 0且不大于 100,000；「允许压降（%）」：必须填写，须大于 0且不大于 20；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) checks its inputs — "Current (A)": required, must be more than 0 and at most 5,000; "One-way length (m)": required, must be more than 0 and at most 100,000; "Voltage (V)": required, must be more than 0 and at most 100,000; "Allowed voltage drop (%)": required, must be more than 0 and at most 20; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.

有哪些选项可以调整？What options can I adjust?

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」的设置：「电流（A）」默认 20；「单程长度（m）」默认 30；「电压（V）」默认 230；「允许压降（%）」默认 3；「材质」可选 铜、铝（默认 铜）；「系统」可选 直流或单相、三相（默认 直流或单相）。每次生成结果都按当前设置处理。Settings in the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) — "Current (A)" default 20; "One-way length (m)" default 30; "Voltage (V)" default 230; "Allowed voltage drop (%)" default 3; "Material": Copper, Aluminium (default Copper); "System": DC or single phase, Three phase (default DC or single phase). The result always uses the current settings.

计算结果可以用于作业或工程吗？Can I use the results for homework or engineering?

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」使用教科书标准公式（公式写在说明和常见问题中），适合学习和估算核对；涉及安全的工程设计请以规范和实测为准。The Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) uses standard textbook formulas (given in the description and FAQ), which is good for learning and checking estimates; for safety-critical engineering follow codes and measured values.

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」免费吗？需要注册吗？Is the Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) free? Do I need an account?

「导线截面积计算器（按压降选线，铜/铝，单相/三相，AWG）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Wire Size Calculator (Voltage Drop, Copper/Aluminium, Single/Three Phase, AWG) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.