发电机导线规格计算器
// 根据 KW、电压、距离和目标压降，初步筛选发电机电源入口、转换开关及备用配电线路的馈线导体规格 //
输入发电机铭牌标示的有功输出功率（千瓦），进行初步导体筛选。
选择发电机的实际输出电压或馈线电压，以便按正确基准校核电流和压降。
纯电阻负载或按铭牌 kW 规划时使用 1.00；发电机负载以电动机为主时，请输入较低的 PF。
输入发电机电源与所接设备之间导体的单程长度（英尺）。
若要对持续发电机负载按 125% 进行规划校核，而非仅按铭牌值直接校核，请启用此项。
12 kW at 240 V, single-phase, PF 1.00
115% minimum generator-output conductor screen per NEC 445.13.
21.1 mm² equivalent, 70.0 A ampacity screen, 2.31 V estimated drop (0.96%).
每一行均根据输入的线路长度，校核所选导体材料和端子额定温度是否同时满足所需载流量及估算压降。
| 规格 | 载流量 | 电阻 | 压降 | 状态 |
|---|---|---|---|---|
14 AWG 2.1 mm² | 15.0 A | 3.0700 ohm/kft | 23.0 V / 9.59% | 增大规格 |
12 AWG 3.3 mm² | 20.0 A | 1.9300 ohm/kft | 14.5 V / 6.03% | 增大规格 |
10 AWG 5.3 mm² | 30.0 A | 1.2100 ohm/kft | 9.07 V / 3.78% | 增大规格 |
8 AWG 8.4 mm² | 40.0 A | 0.7640 ohm/kft | 5.73 V / 2.39% | 增大规格 |
6 AWG 13.3 mm² | 55.0 A | 0.4910 ohm/kft | 3.68 V / 1.53% | 增大规格 |
4 AWG 21.1 mm² | 70.0 A | 0.3080 ohm/kft | 2.31 V / 0.96% | 通过 |
3 AWG 26.7 mm² | 85.0 A | 0.2450 ohm/kft | 1.84 V / 0.77% | 通过 |
2 AWG 33.6 mm² | 95.0 A | 0.1940 ohm/kft | 1.46 V / 0.61% | 通过 |
1 AWG 42.4 mm² | 110 A | 0.1540 ohm/kft | 1.16 V / 0.48% | 通过 |
1/0 AWG 53.5 mm² | 125 A | 0.1220 ohm/kft | 0.91 V / 0.38% | 通过 |
2/0 AWG 67.4 mm² | 145 A | 0.0967 ohm/kft | 0.73 V / 0.30% | 通过 |
3/0 AWG 85.0 mm² | 165 A | 0.0766 ohm/kft | 0.57 V / 0.24% | 通过 |
4/0 AWG 107.2 mm² | 195 A | 0.0608 ohm/kft | 0.46 V / 0.19% | 通过 |
250 kcmil 126.7 mm² | 215 A | 0.0515 ohm/kft | 0.39 V / 0.16% | 通过 |
300 kcmil 152.0 mm² | 240 A | 0.0429 ohm/kft | 0.32 V / 0.13% | 通过 |
350 kcmil 177.3 mm² | 260 A | 0.0367 ohm/kft | 0.28 V / 0.11% | 通过 |
400 kcmil 202.7 mm² | 280 A | 0.0321 ohm/kft | 0.24 V / 0.10% | 通过 |
500 kcmil 253.3 mm² | 320 A | 0.0258 ohm/kft | 0.19 V / 0.08% | 通过 |
Use this calculator for fixed wiring between a generator, inlet, transfer switch, disconnect, or downstream distribution equipment. If you are sizing a portable cord set instead, use the extension cord tool and verify the cord listing.
- 发电机馈线导体仍需就过电流保护、转换设备认证，以及适用于该安装的中性线或接地规定进行最终复核。
- 此处的压降限值是规划目标，并非 NEC 的直接强制要求。敏感设备和电动机启动工况通常需要采用更严格的压降限值。
- 本工具适用于发电机与下游设备之间的固定布线，不适用于柔性便携式软线组件或临时布线审批。
7.5 kW portable generator to 30A inlet
At 240 V single-phase and 60 ft one way, the calculated current is about 31.3 A. 10 AWG copper has enough ampacity but usually pushes above a tight 2% drop limit, so 8 AWG becomes the cleaner fixed-wiring choice.
20 kW standby generator to transfer switch
A 20 kW, 120/240 V single-phase unit delivers about 83.3 A at PF 1.00. With a 100 ft run and 3% target, 3 AWG copper can be a practical planning result before final OCPD, neutral sizing, and grounding checks.
60 kW three-phase generator feeder
On 480 V three-phase at PF 0.9, load current is roughly 80 A. Voltage drop is modest at this voltage, so the selection is often driven by ampacity, terminals, and installation conditions rather than distance alone.
Voltage Drop Calculator
Run a broader AC voltage-drop check after the generator circuit layout is known.
Ampacity Calculator
Review terminal temperature, bundling, and derating before final conductor release.
Conduit Fill Calculator
Check raceway occupancy once phase, neutral, and grounding conductors are selected.
Cable Size Calculator
Compare the generator feeder result with a broader residential or commercial sizing workflow.
Wire Resistance Calculator
Audit raw conductor resistance if you want to inspect the voltage-drop math directly.
Wire Weight Calculator
Estimate pull weight and reel handling for larger standby generator feeders.